all other approaches
approaches do not have vertical reference other than the altimeter and the
direction of the approach may not be aligned with the runway. You will be
expected to manoeuvre for the landing. The minimum descent altitude (MDA) may be
very near the low IFR altitude of weather. The MDA may be relatively high
depending on distance, terrain, and type of approach. You cannot leave the MDA
without seeing the runway. Just seeing the ground is NOT enough.
The design limits of the system
set the minimums. The approach is named by the navaid and runway at the airport.
The navaid may be before, beside, on, or beyond the airports. A margin of error
is built into the plate by TERPS (rules for making approaches) but the
expectation is that the pilot will fly the procedure perfectly so as to maintain
these safety margins. The non-precision approach usually does not parallel the
runway centreline; instead the electronic line takes us to the end of the runway
at an angle. There is no electronic vertical guidance. A turning manoeuvre is
going to be required for landing. The MDA will vary with the terrain, lighting
available and system used
A pilot has a choice of doing
the approach with vectors or as 'own-nav'. Vectors are easier since ATC usually
sets you up with a 30-degree intercept to your inbound course. Your 'own-nav'
may require that you reverse your direction of arrival. This means using a
procedure turn or a holding pattern to make the turn-around, and begin your
descent when established. There are required reports at the fix inbound and when
established from the procedure turn.
The chart will have course,
altitudes, frequencies and times for you to utilize during the approach. The
approach is segmented into three parts:
1. Initial segment gets you lined up for the approach.
2. Intermediate segment usually begins the descent.
3. Final segment gives you a timing point, minimum descent(s), and missed
4. Missed segment which begins at the missed approach point with a direction,
and climb required.
A non-precision approach has
four segments; each segment begins at a defined point. The initial approach
segments begins at the IAF. At the intermediate approach segment you are
established on course and descending. The final approach segment usually has a
FAF but not always from which time or DME is used to guide the descent to the
MDA. You do not leave the MDA until seeing the runway. The fourth segment is
from the missed approach to the missed approach fix. The route and altitudes for
each segment are shown in plan and profile views. By flying the published
headings and altitudes you are protected from obstacles.
Being "Cleared for the Approach"
by ATC means that you can follow the published procedure. By following the
publish routes at the published altitudes you are 'guaranteed' not to hit any
ground object. That is, providing you have correctly set your altimeter.
Historically the 'chop and drop' has been the accepted procedure and could be
used in familiar situations. Otherwise, the stabilized approach using the
airspeed, time, and descent rate is to be preferred. Descent from the FAF to the
MDA have traditionally been of the 'chop and drop' type but today the use of DME
makes stabilized descents more common. The VDP (visual descent point) either
created or charted makes it possible for the pilot to prepare for a landing for
straight in approaches.
The purpose of the non precision
approach is not to put you on the runway. Its purpose is to get you down out of
the clouds and in sight of the runway. The pilot is expected to navigate to the
missed approach point. Only if clear of the clouds will he will be allowed to
manoeuvre visually to the runway. MDA are usually below standard pattern
altitudes and will require a higher level of manoeuvring skill. Practice your
short approaches in better conditions.
If you descend to the MDA and
see the runway but not in time to make a normal landing, you must climb to
circling minimums before turning. In the turns you are required to keep the
airport in sight at all times. You do not descend below circling minimums again
until lined up with the visible runway. Non-precision approaches at night should
only be flown if there is a VASI. If at first you do not succeed…quit and go to
a better place. Most approach accidents occur during the second attempt.
You can use or make a visual
descent point (VDP) as a landing aid. TERPs require a VDP for all straight-in
non-precision approaches except for procedures with remote altimeter setting,
where the descent path is below a required step-down altitude and where it would
be between the MAP and runway. No VDP will exist where an obstacle exists. The
absence of a VDP serves as an obstacle alert.
The VOR and NDB approaches do
not have the options of precision approaches. Only Minimum Decent Altitudes
exist. The circle to land minimums have Height Above Airport numbers
parenthetically rather than runway numbers. The circle to land altitude and
distance is determined by aircraft category speed. For straight-in minimums
there are three requirements:
1. Approach aligned within 30-degrees
2. Approach must cross the runway threshold
3. Descent gradient cannot exceed 400 feet per nautical mile.
Non-precision approaches, while
less accurate, are easier to fly because the altitudes are mostly level flight
with only one needle to follow. On reaching the minimum descent altitude you
should have established a personal visual descent point from which a normal
straight-in landing can be accomplished. Other wise do not descend below the
Localizer types of non-precision
approaches are the localizer, LDA and SDA. Other non precision approaches are
the VOR, and the Airport surveillance radar approach (ASR). ASR approaches
require a published plate. A given approach may be entered as (1)a straight in
approach or (2) as a full approach.
--Once on the approach use power
for descent, level and climb
--Work load must not interfere with control.
--Focus only on the turn when turning.
--Consider downwind landing instead of circling.
--Make small power changes even to climb.
--Never bust minimum altitudes.
Descent from the FAF to the MDA
have traditionally been of the 'chop and drop' type but today the use of DME
makes stabilized descents more common. The VDP (visual descent point) either
created or charted makes it possible for the pilot to prepare for a landing for
straight in approaches.
Approach Minimums for Non-precision
Circling minimums require a ceiling.
Get down to the MDA well before the airport.
You win by being allowed to make a scud run to the airport.
Nonprecison approaches should be flown precisely.
Level off at the MDA and let person not flying look for airport.
Complex Approach Minimums
Lowest minimums only if:
1. Local altimeter setting
2. Identify 2.5 DME fix
3. Straight in landing
Stepping Up to the Step-Down Approach
The step-down is used to give the
non-precision approach lower minimum descent altitudes. The basic non-precision
without the step down takes you to the MDA right after the FAF. The step-down
requires that you make one or more altitude stops before reaching the MDA. The
steps are based upon aircraft category and the altitudes are critical with
minimal obstacle clearances.
There are two methods of doing the approach. One is to follow the published
procedure and chop-and- drop between each step while maintaining a constant
ground speed in the drop and level flight. The other option is to calculate the
rate of descent for the entire procedure and initiate that rate of descent at a
constant ground speed throughout. The latter procedure will allow you to cross
each fix at the proper altitude in a stabilized airspeed approach.
Take all the training you need to
get rid of any inefficiency or poor techniques. Unless you have begun your
landing descent at a valid visual descent point (VDP) with the required visual
references you must make a go-around. Primary to any go-around is the immediate
application of all available power. You do not have full power unless you take
off carburettor heat. Do NOT look into the cockpit. Keep your eyes outside. Hold
heading with rudder. Lock your elbow against the door and fly level holding
heading. Lose altitude if you must, the aircraft will fly and accelerate better
in ground effect. On reaching climb speed as determined by sound or a quick
glance. Remove flaps only if necessary for climb. Initiate a climb.
If you do not have the runway at
MDA/DH, you may not be where you should be. In this case you cannot afford to
lose altitude. Leave the plane in a landing configuration if it is able to climb
reasonably well. Practice making full ‘dirty’ go-arounds at altitude. Also
practice getting a better climb after you are well into the go-around.
Don’t press a touchdown that is
going to be long on a short runway. When there are strong cross winds expect to
make your go-around early in the approach when your needles have trouble finding
Flight visibility is the governing
factor in Part 91 instrument approaches. The reported ground visibility is a
factor only in that the FAA may call your 'flight visibility into question. One
way to improve your preparation for the missed is to incorporate your missed
approach configuration of gear, flaps, and airspeed into your approach
The use of an autopilot-coupled
approach presents a problem if the missed approach is not also coupled to the
autopilot. I have had pilots have real difficulty with the missed because of the
transition from autopilot into a hand flown missed.
When things go wrong on an
approach the best option, as in other landings, is to go-around as required by
the missed approach procedure. This is recognized as a very correct --command
decision. The decision is followed by the number one priority of flying the
airplane. You do this by applying full power, cleaning up the configuration at a
The decision altitude or minimum
descent altitude is the height above touchdown elevation and not the runway
threshold. The importance of flying a clean approach is that you will be
executing the missed approach in protected airspace. The accident record of
missed approaches is that only about five related fatal accidents occur per
year. Considering all the missed approaches made this is a very good record.
You are in protected airspace
that extends for 15 miles with a 40' to 1' terrain clearance plane, which
requires a climb rate of 253 fpm. Do not make any turns until reaching the
specified plate altitude. Turning too soon can be just as fatal as turning too
late. Breaking off an approach requires that you climb straight to the missed
approach and follow the published turn procedure.
If you are flying the circle to
land approach, the missed approach procedure requires that you circle back to
the runway with the missed approach procedure. You are not obligated to then fly
to your alternate. The purpose of the alternate is to advise ATC what to expect
if radio failure should occur.
Don't try to hard to succeed on
an approach. Pushing your luck and skill is the road to failure. Making the
missed approach means that weather was below minimums, not that you were a
failure as an instrument pilot.
Failure to initiate the approach in a timely manner statistically kills far more
pilots than does the missed. The worst killer is the second approach made
because the pilot saw the runway in passing.
second guess the go-around. Do it!
Use full power
Hold heading and altitude until reaching climb speed and afterwards.
Climb with flaps if you can.
Clean up plane.
The tower is not responsible for any
traffic separation until that traffic is on the ground but arriving traffic must
be far enough out to allow surface traffic to clear the runway before touchdown.
There is no ATC separation by the tower while you are in the air even though you
may be talking to the tower. There is a hazard associated with the straight-in
approach. Aircraft viewed directly from the rear are difficult to see since
there is no relative motion. Motion is the first thing the eye sees. An airplane
both in front of you and lower is even more difficult to detect. Use the radio.
The straight in approach is so
called because it does not use a course reversal to become established on final
course. Radar vectors can be used to bring you so as to intercept the final
approach course. A no procedure turn (NoPT) transition is possible when the
feeder route has both direction and altitude for an easy intercept and descent.
An approved transition must have a minimum altitude, distance and heading.
Approaching from a hold is allowed when the inbound leg is aligned with the
final approach course. May be prohibited by note. The DME arc is a curve route
to intercept the final approach course. NoPT is required but DME is. Per the
FAA legal interpretation, unless cleared otherwise by ATC, intercept the arc at
Straight-in minimums are not published or available when the final approach
course is not within 30 degrees of the runway centreline OR a normal rate of
descent cannot be used from the MDA to the runway. When the approach plate has a
number as part of its title then the runway is within 30 degrees and the
straight-in is authorized and the minimums are published. Any time you fly such
an approach with a crosswind component corrected by your heading, the airport
will not be over the nose of the airplane.
At many airports the approach to
the runway on the chart may require either a downwind landing or a circling
approach. Lower minimums will apply to the downwind landing. You will
need to adjust your airspeed to get the desired ground speed caused by the
tailwind. If the tailwind is only 10 kts it will double your
No different than when first used
Two focused directional antennas at 90 and 150 Hz
Signals overlap from departure end of runway down
centreline for about 18
Aircraft receiver compares amplitude (power) of signals to get 1 to 1 ratio
existing only on centreline.
Blue or shaded side of approach is always to the right.
Back courses reverse sensing of ILS requiring pilot to fly away from needle
unless reversal built-in.
6 degree course accuracy to threshold.
OBS should be set to approach course as a reference heading only.
Back course ILS is non precision localizer approach.
Localizer directional approach (LDA) flies like a localizer approach but can
bring you in to runway from 30 degree angle.
Some LDAs have glide slope.
Simplified directional facility (SDF) approaches uses poor quality antenna
with course width of 6 to 12 degrees.
Use approach chart to obtain reference descent rate in fpm.
Bracket this rate to get and keep correct slope
Your primary pitch instrument for straight and level at the MDA is the
altimeter (the one with the numbers).
A clearance to the ILS approach is likewise a clearance for the localizer but
with higher minimums.
An ILS/localizer approach has two FAF's only one of which is timed. The
interception point of altitude with glide slope is the FAF for the ILS.
You cannot fly the Localizer if you have flown the ILS to below the MDA for
The LOC (localizer) only and VOR approaches look pretty much the same as an
ILS except that they don't have the "go up/go down" glideslope needle, just a
"go right/go left" needle.
The VOR and localizer are on independent circuits. They require independent
A localizer can be checked for
accuracy by departing a runway served by that localizer. Tune to LOC frequency
while taxiing and note CDI movement as you move on to runway. CDI should center
as you line up on runway centreline. This will not work at CCR 19R except at the
very end of the runway due to offset. VOR frequencies end with an even decimal:
.2, .4, .6, etc. Localizer frequencies end with an odd digit: .1, .3, .5 etc.
Item: VORs with HIWAS do not have two-way communications.
91.25 Requires 30 day check of VOR accuracy before IFR use.
Use of VOT give zero From or 180 degrees To with allowable error
Ground checkpoints in AF/D
Airborne checkpoints in AF/D
Dual VOR check within 4 degrees
VOR idents in a series of four followed by DME ident.
VOR deflection is 10-degrees from
centre to side
Any time dual VORs have a common problem it is probably the shared antenna
On a VOR approach, the VOR can
be located at:
Missed approach point
Initial approach fix
Final approach fix or
Miles from the airport.
Fewer options for the VOR and NDB than for the ILS. Some non-precision
approaches lower the minimums when light systems exist. The MDA boxes do not
include DA(H). Circle to land minimums are based on HAA elevation as shown on
the right side of the chart. Numbers in parentheses are Heights Above airport (HAA).
Radius of the circle for category A aircraft is 1.3 nm. The speed you fly
determines the aircraft category. If there is no speed/time chart then timing is
1. Runway alignment within 30-degrees
2. Approach must cross threshold
3. Descent to be less than 3.77 degrees or 400' pnm.
Intercepting a Radial
an airway a 45 degree intercept
On approach use 30 degrees
10 degrees maximum on the ILS and use rudder for 5 degree corrections
In some instances a greater than
30-degree arrival may not require a hold. The FAA may design an approach where
the hold is so removed from the final approach fix (5 nm) that sufficient time
for course alignment exists.
There are 6 ways a VOR can be pilot
checked for errors:
Ground check point
Dual VOR check
Radio shop check
--Designated airborne check
Every VOR has a dedicated
monitoring system where other navaids may or may not be monitored. Monitors
check the signal and any required accuracy on a status panel with alarms and
lights. Unmonitored navaids cannot be used to meet alternate requirements of IFR
flight and are noted in the A/FD either with and N/A on an approach plate or
with a ‘tower closed’ note. The pilot who is using an unmonitored navaid for an
actual approach had better maintain a constant listening watch on the frequency
The NDB approach is designed to have protected minimum obstacle
clearance is 300 feet vertical and 1.25 miles wide at the facility. A formula is
used to determine the protected space as the missed approach point which amounts
to 6000' wide per mile. You have 30 degrees angular space, 15 degrees to each
side, to miss the runway and still have protected airspace. The PTS standards
allow only 10 degrees bearing error to the approach course.
Low frequency radio 200-1600 KHz
with both loop and sense antennas. Not limited to line-of-sight but by power. HH
power good for 200 miles down to compass locator or locator outer marker (LOM)
at 15 miles.
The ADF course is the intended
magnetic flight direction. When ATC directs you to fly with reference to an NDB
they will always give a bearing from or to the station. The to
or from may be either way by ATC while meaning the same thing. If you are
in doubt as to ATC intentions reverse the term and direction used by ATC and ask
Rotating the azimuth card makes
the ADF into a pseudo Radio Magnetic Indicator (RMI) without the remote compass.
In the RMI the azimuth card rotates automatically. With the ADF you must set the
card to the desired magnetic heading. The heading selected in the course line +
the predicted wind angle. You are trying to get the tail of the needle to
indicate the approach course line. When the tail of the needle indicates to the
right of the course line you will turn to the right for about 30 seconds before
returning to the WCA heading. Works the same if the tail moves to the left. Once
you have turned the card it is best to leave it alone unless you have grossly
misjudged the WCA.
When NDB is used to form airway the magnetic bearing from the NDB is used to
form the radial.
--An unused ADF is likely to get needle problems
Not all ADFs use two antennae.
Check an ADF malfunction by going to ANT mode (Some needles will 'stow' at 90
Set HI with compass
Turn to fly direct to NDB
Fly until needle is off the heading. Its deflection is the wind direction.
Turn to the needle twice the displacement.
When needle deflects by the original deflection amount, take out half the
correction and see if needle stabilizes as a indication of correct drift
Repeat the process as distance permits.
On station passage turn to inbound course with wind correction applied.
Use NDB course line as wing leveller.
Standard Outbound Tracking
Initially the needle is at 180
Hold the course but any needle movement indicates direction of the wind.
When needle is displaces 5 degrees, make 20 degree turn toward needle.
When needle tracks 20 degrees take out 10 degrees.
You will know you are tracking correctly when needle deflection is constant.
Repeat as necessary.
Intercepting a Bearing:
Turn to desired magnetic heading. Needle deflects to station.
Turn toward needle double the deflection.
Fly heading until needle deflects half of intercept angle.
Turn to original desires heading. Needle should be centred.
Repeat as required.
If you are constantly correcting you heading to fly to the NDB, this is an
indication that you have not made a wind correction and are flying an arc to the
NDB. Without the wind correction information that should be determined inbound
to the NDB, you have only one option. Fly the charted bearing from the station.
This is not the way it should be done but this method has a good chance of
keeping you within the allowable error range.
Set magnetic heading of aircraft to the top of the ADF card.
Tail of needle gives bearing from station.
The ADF can detect thunderstorms
ADF needle is unreliable in a turn. Use timed turns for changes.
Monitor frequency when sole source of navigation.
Consider putting magnetic bearing to the station on top.
Once established make only small heading changes.
Simple NDB Approach
The difference between the NDB and the others is that there isn't a
single dial in your cockpit that you can refer to, to see your tracking error.
You must combine the information presented by the HI and the ADF, if you wish to
accurately track to or from an NDB
You can practice learning to track using the NDB. When flying cross-country,
work on finding the proper crab angle. Good visualization practice. But during
the approach, people under stress may misinterpret the dials and ‘correct the
wrong way. Flying the NDB approach, which has an NDB located 4 miles west of the
threshold of runway 09.
270 <----- /------- * -- 090 -->
9__________________|/045 / 225
When cleared for the NDB 09
approach, so you could simply "home" to the NDB, which is your IAF (Initial
Approach Fix). ‘Homing’ with an ADF simply consists of keeping the needle on the
‘nose’ of the aircraft, or on the zero at the top of the ADF indicator. With a
crosswind, our just flying the needle will get us there. Spend any excess time
studying the plate.
Get the important items:
A pproach - the right plate?
M inimums - MSA, PT, FAF, MDA
O vershoot - quickly review which way, how high, how far
R adios - ADF tuned and identified. Radar, ATC, CTAF
T imes - get a time to the Missed Approach Point (MAP), VDP?
S peeds - groundspeed based on wind
Passing the NDB outbound, some
type of procedure turn. Course reversal is easiest but always to the published
turn side. Otherwise, visualize what the wind is doing to you on each straight
leg of the procedure turn, and make a correction for it. A crosswind, crab into
it. A headwind, increase your time significantly. A tailwind, decrease your time
slightly. Headwinds hurt more than tailwinds.
Cockpit checks now. Check your Heading Indicator against the compass. You
cannot fly an accurate NDB approach without an accurate heading reference.
Major NDB problem is lack of ident process. NDB navigation relies on the
accuracy of the compass. Compass deviation must be applied to NDB bearings.
Avoid flying an NDB using an outbound track from a distant station. Configure
before beginning the approach. Don’t home, track to an NDB. This means apply a
course correction that negates the wind effects. NDB station passage is noted
when the needle is off the wingtip.
High powered AM stations can be good for 500 miles. The accuracy of the ADF is
directly related to the accuracy of your compass and your HI setting. Compass
corrections of the compass apply to the NDB. The recency of a compass card is
Flying an outbound NDB track from a distant beacon should be avoided. Before you
start on approach you must be configured and on speed. Homing does not work
inbound. Track to an NDB if you want to remain in protected airspace. You must
track outbound from an NDB by getting on the outbound bearing and then
correcting for any crosswind to remain on that track. This must be done before
starting on the approach.
Final Approach Tracking.
Turn initially to a heading of 090 and begin descent started to get your
altitude for the FAF (Final Approach Fix). This is usually lower than your
procedure turn altitude. Be sure to keep a 500 fpm descent rate going, use 600
or 700 fpm if you have a tailwind.
If there's no wind, a heading of
090 will take us right to the NDB. Rather than using any tracking and correction
technique just simply home to the NDB. Needle on the nose, back to the NDB. By
homing to the NDB, we are assured of a station passage. On Passing the NDB (the
FAF) inbound, turn back to 090 and start a descent, down to your MDA (Minimum
Descent Altitude). Essentially, after station passage just fly a heading of 090
until you see the runway, or your timer runs out at the MAP. At a ground speed
of 90 knots, it will take 2 minutes to travel 3 nautical miles to a 1 mile final
for runway 09, at which time you should be visual with the runway, and start
your descent from the MDA.
But let's say we've got a 30
knot direct crosswind, which is a lot at 500 feet AGL. If we get a good station
passage, and just ignore the wind by flying a heading of 090, after 2 minutes
the crosswind will have pushed us 1 nm off course. Instead of being 1 mile from
the runway threshold, we will be 1.4 miles, which is a pretty good return for
such a simple procedure.
If you think about it carefully,
it's actually going to be better than that. With a strong wind from the north,
while homing to the NDB after the procedure turn for the FAF, let's say we
eventually weathervaned to a heading of 070 at station passage. After we pass
the station inbound, during our turn from 070 back to 090 we will travel
somewhat north, or upwind of the desired track, so we probably won't drift a
whole 1 nm downwind.
Also, if you have a higher
groundspeed than 90K, you will be affected less by the crosswind. There's less
time for the crosswind blow you off course after passing the FAF. The neat thing
about the above NDB approach is that at no time did you ever have to track using
the ADF. You always flew and maintained headings.
NDB Cold approach
The NDB is the easiest 'cold approach' to make.THE COLD APPROACH (no
opportunity to use the 6 p's)
Frequencies at top of chart Locate VOR's relative to approach
Check/recheck OBS settings
Write time and MDA/DH on hand
The side of the published procedure turn is mandatory
A published teardrop procedure is mandatory
The completion distance from the fix is mandatory
It is TOO LATE to study the plate inside the FAF
Base all wind corrections on the point of the ADF needle.
The arrowhead will point the direction the wind is going.
You should know that the NDB
power and range are in the Airport/Facility Directory. The ADF needle always
points to the station and the tail of the needle give the aircraft position. To
get your magnetic bearing to an NDB you must use your imagination to put the ADF
needle over the HI. Changing the ADF card makes the process more difficult,
leave it on zero.
The curved path that occurs when
flying to the NDB without any wind correction is called a oxodromic curve. Tune
in the frequency and the needle will always point to the station. The needle
that is not pointing to the station will either point to the left or right of
the station. Make your correction for wind or course by correcting to the
direction of the needle, left or right. In each case you must make a heading
change that is greater than the needle deflection.
You should not try to track a course until you have intercepted the course. Once
intercepted you must track with the understanding you will need to intercept
again and again. This is especially true in NDB holding patterns.
Slightly modify the above procedure. With a groundspeed of 90K, we know that two
minutes after passing the FAF we should be visual with the runway, and in
position to start descending on final. So, passing the NDB inbound, turn to a
heading of 090 and hold it as accurately as you can for one minute. After one
minute, observe the ADF indication. Let's say that it's now 190 relative. This
means we have drifted south (to the right) 10 degrees during the one minute
after we passed the FAF.
To correct for it, we turn left 20 degrees to a new heading of 070 for the
remaining one minute. This 20 degree correction for a 10 degree drift is exactly
the same track correction method you used as a student pilot on your private
pilot flight test.
Newer is not always better. Within a mile at low altitudes the VOR is
more accurate than unaugmented GPS. The GPS is always better than the NDB for
accuracy. The two levels of GPS use are the Standard Position Service which is
within 100 meters 95% of the time and within 300 meters 99.99% of the time. The
second service is for the military only as precise positioning Service.
Can predict loss of signal.
The antenna is not shielded by structure
Broader data base.
GPS will provide for non-precision
operations into small airports. The presence of obstacles may not be depicted.
GPS is not conducive to windshield scan. Best to have a third person aboard who
is supposed to watch for other aircraft.
IFR has a higher level of skill requirement but the use of ATC services,
especially radar, is a given so the process is simpler. If you plan to use a GPS
approach at a given airport, your alternate must have an instrument approach
procedure other than the GPS. IFR GPS must have FAA approved flight manual
supplement and current database. Must query FSS for GPS NOTAMs. File as /G
using the FAF as a waypoint instead of the Airport you can get the distance to
the runway threshold.
Ask for spelling of waypoints and intersections used in your clearances if you
plan to use GPS.
The unusual spellings of waypoints are called 'neologisms.
GPS approach descents often have VDPs. (Visual Descent Point)
VDP is based upon MDA (minimum descent altitude) and required visibility to
GPS use is not authorized as substitute for DME or ADF if information is not
VDP are located so that a normal approach to landing can be made if the
airport is in sight.
Use GPS course line as wing leveller.
Garmin 530 (430)
Failure to hit the GPS/CDI (Course Deviation Indicator) switch before and
after the approach can kill you.
Before the FAF you must be on GPS; on the approach you must be on CDI; on the
missed you must be on GPS
An autopilot with heading and altitude hold is essential if you expect to use
the GPS without a copilot.
Never try a GPS procedure the first time in a non-radar environment until you
have flown it in VFR first.
Revert to vectors when ATC gives you your first initial heading to intercept
the final approach course.
Activate the approach when ATC clears you for the approach.
1. While en route select the approach you are going to use.
2. Select the transition IAF you expect to use. When cleared for the approach
and assigned a crossing altitude, you can…
3. Activate the approach--If ATC does not use your anticipated IAF you must
reload the GPS from setup #1.
4. Change is from the airport as the GPS destination to the CDI with the IAF as
the active waypoint.
The GPS cannot fly the missed
Any approach not approved for the GPS will take you through the approach but
will not remind you to
go to GPS for the missed.
The missed will be a straight out on the course line as a
rather than the published missed. You must use paper.
Do not fly a dashed line do not use the GPS which will fly you direct to the
missed fix. This may fly you into a mountain.
New GPS precision approach plates include stabilized approach angle and
decision altitude instead of MDA.
GPS non-precision approaches will include glide angle, visual descent point,
and threshold crossing height (TCH) where descent angle crosses threshold.
VGSI is new FAA term (visual guidance slope indicator). This is used on
non-precision GPS approaches where
the approach slope is actually above the VASI slope.
Non-precision GPS approach uses a MDA so it is important not to go too fasts
and avoid a long landing.
A published VDP should be used as a missed approach point because circling is
The missed approach can only initiate a climb, no turn is allowed until past
GPS in an Emergency
You can use GPS to position yourself on short final to a runway under the
worst conditions if you have practiced a
relatively simple procedure. There are several requirements.
You must be able to fly timed distances on precise headings.
You must have an aircraft that is willing to remain airborne.
You must have a GPS receiver with a suitable data base.
You will need to fly a modified airport pattern much as you would in VFR
conditions. Try this lesson in VFR conditions around a seldom used airport until
you perfect the procedure. GPS locates an airport by a reference point called
the ARP. This point is usually near the center of the airport itself. You want
to remain relatively close to the airport. You intercept a direction to the ARP
that is 90 degrees to the longest runway. Since you want to be about 1/2 mile
from the runway on your abeam the numbers downwind you will anticipate your turn
to downwind by turning when .3 from the ARP (Airport Reference Point). A
standard rate turn should position you about 1/2 from the runway on a parallel
track. Turn base at 1 mile from the ARP and make an early turn to final to a
heading that will allow a 30 degree intercept to the bearing to the ARP. The
descent throughout the procedure should be from pattern altitude and at approach
speed before turning base. A normal descent should place you over the runway
with some excess altitude as a safety margin. Never accept an ATC final approach
speed higher than your flap or gear speed.
GPS as a Substitute
Locate DME fix
Fly a DME arc
Fly to/from NDB
Locate NDB cross-bearing
Hold at NDB
Emergency ADF Use:
If you lose your AI, HI, etc. and need to fly a particular heading, you
can use the ADF as a very useful and reliable aid. Tune to the most powerful
station available. With that as a guide you will be able to fly straight and
make turns by the required number of degrees.
A visual approach allows an aircraft on an IFR flight plan to fly in VFR
conditions under ATC control to an airport. Clearance requires VFR conditions at
airport and en route, airport in sight and any traffic in sight.
Visual approaches are not an instrument approach, rather they are an IFR
procedure giving means for avoiding a full IP during good conditions that avoids
cancellation of your IFR plan. Local weather of VFR minimums is required. The
pilot is responsible for all obstacle clearance and has given up the right for a
missed approach and going IFR again. Recommended altitudes are mandatory as is
the recommended flight track. Part 91 visibility have never been defined. You
are protected from IFR planes you do not admit seeing. Visual approaches greatly
increase the PIC responsibility of the pilot.
You are not on an instrument approach procedure even though you are adhering to
instrument flight rules. If there is any doubt as to the success of a visual
procedure, you should remain IFR. Both visual and contact approaches must be
flown in VMC. A visual approach can be flown to any airport if ceiling and
visibility are above minimums of 500' above minimum vectoring which is always at
least 1500 AGL. Though similar, the visual and contact approach are not
Either ATC or pilot can initiate visual approach when you can tell ATC you have
the airport in sight or if you have preceding traffic in sight and will maintain
separation and wake avoidance. If you see the airport but not the traffic
ATC must provide separation. Radar service is terminated when you change to
tower frequency. The visual approach clearance does not include missed approach
instructions. Missed approaches are handled as a go-around.
A visual approach requires a 1000’ ceiling and 3-mile visibility. What you do
visually depends on the ATC clearance. If you are cleared for a named and
charted visual approach, you must fly the charted procedure. If your clearance
is not named and charted you can fly VFR to get where you are going.
To conduct a visual approach you must be on an IFR flight plan and have airport
or traffic in sight with weather at least 1000 and 3. ATC can give clearance at
an airport without reported weather if 1000 and 3 is expected. Visual approaches
are allowed even if vectoring weather minima do not exist as long as 1000 and 3
do exist. If there is no weather observer the radar controller must be told that
you are VFR before he can give you a visual approach. Once you have accepted a
visual approach, you are responsible for all traffic separation.
Imagine that the airport/approach is a beautiful woman. You can have visual any
time you want, but you've got to request contact.
ATC or pilot initiation
Ceiling 1500' or better or pilot must be able to maintain VFR.
Pilot maintains separation and wake avoidance
Can be offered by ATC or asked for by pilot if ceiling is 1000’ and visibility 3
miles. You must remain clear of clouds. You must have any preceding traffic or
the airport in sight. Traffic and wake avoidance is up to the pilot.
On top conditions may be difficult in convective conditions. Clouds often rise
at 3000 fpm. Let ATC know so you can file IFR. Ask for an alternate IFR
clearance in case of communications failure. You must see and avoid all other
traffic but also report all altitude changes as though IFR.
If you are dealing with IFR as a process within a complex maze of strict,
unwavering rules requiring passive compliance, they you don’t know how to use
and fly the system. there are a number of time and fuel saving ways of using the
system to your advantage.
Once you accept a visual approach from ATC you are responsible for wake
turbulence avoidance. If doubts
exist be prepared to query ATC as to ground speeds and separation.
The visual approach does not require that the airport have an
instrument approach or SIAP
You will fly to a specific navaid point and be cleared for the visual
You must see either the airport or traffic to be followed.
You should expect to get an escape clearance if things go wrong.
You are in IFR conditions and below minimum vectoring altitudes.
An IFR pilot can shift
responsibility, control and liability out of the hands of ATC by requesting a
contact approach. This allows deviation from published procedures and allows
flight to the airport where visibility is reported to be at least one mile. The
pilot must maintain ground contact, remain clear of clouds and provide obstacle
clearance. Only you, the pilot, can do this; ATC cannot. The contact approach
has the pilot responsible for terrain clearance, clear of clouds and flight
visibility. ATC must have a procedure (including the published misssed)
available should IMC flight be required by the pilot unable to maintain the
Don’t descend until in position to land. Obey minimum safe altitudes and
obstruction clearance features. This is a form of scud-running that is safe only
if you are familiar with the area. Don’t ask for a contact approach unless you
really know where you are and will be all the time. You must have one mile
visibility and fly clear of clouds as though SVFR. One mile visibility can
suddenly go lower. Don’t hesitate to contact ATC and get an approach clearance.
ATC will provide separation only from other IFR traffic and SVFR traffic. The
contact approach is a substitute for an IFR approach.
Must be pilot requested and ATC approved. Only airports with IAPs and weather
reporting. Cannot be used to reach other airports. Pilot is responsible for
obstacles and radar service ends with frequency change.
--The contact approach can only be asked for by the pilot.
Minimum conditions are 1 mile visibility and clear of clouds.
ATC does not like the contact approach since its safety is directly related to
how familiar the pilot is with the area.
ATC will never clear a contact approach aircraft below the local minimum safe
Requested by pilot
Clear of clouds and
1 mile visibility
Pilot responsible for obstacle clearance
Saving Time and Money
The contact approach is a way to use the system more efficiently
The contact approach reduces the time to destination.
Preferred routing in and around Class B airspace is circuitous
On IFR plan and you see the ground surface you can request a contact approach
The airport must have a standard or special IFR approach.
The SIAP or special instrument approach procedure is your escape if the
contact approach doesn’t work.
A contact approach is an IFR approach.
There is no altitude restriction
Approval is required by the tower and may be required from the radar
Once cleared for the contact approach you are out of the IFR approach system.
Once cleared you must fly visually using SVFR minimums to the runway.
You are responsible for obstacle avoidance.
Standard separation is applied from other aircraft.
Do not continue a contact approach if you must enter an IFR condition.
ATC and Visual Approaches
Determines airport visibility
Gives alternate (missed) instructions
Provides separation until handed off to tower
Contact Approach ......................................................Visual
Only pilot initiated
......................................................Pilot or ATC
Airport required to have instrument procedure charts ..Vectors possible
Clearance must include missed
Basic VFR minimums exist and can be maintained
ATC has 1 mile at airport
ATC radar separation
SVFR minimums for pilot and ATC ................................1500' and 3
Pilot obstacle clearance
.................................................Maintain basic VFR when cleared
Enables file IFR to airport without weather reporting.
Area weather must forecast VFR. (New night VFR)
Only at airport with instrument procedure ........................Clearance
limit to nearby intersection
Airport reporting statute mile ground visibility.
Not to be used to transition to another airport.
The release of an aircraft to tower frequency ends radar service. There have
been many instances where the has been verbal confusion between the pilot and
ATC. ATC asks you to have runway in sight, you respond with,
"airport in sight". there is a difference and the difference has resulted in
many wrong-runway landings as well as wrong airport landings. Additionally ATC
records show that pilots are often mistaken when reporting, "Have traffic".
Types of Vectors
Long-range provided by
Short-range into a instrument approach procedure.
Delay or spacing vectors for traffic separation
Re-route as a short-cut
Shortcut to IAP segment not final approach. Limited radar coverage you are
required to make any procedure turn. 91.175(j) Usually safer to fly the full
Weather avoidance requests by pilot and his responsibility.
Departure during climb but below MVA. Only on IFR departure or on missed. May
be above MVA or MIA
To final so no published course reversal required. 20-30-degree intercept
angle. Don’t turn on to final without ATC approval.
Pilots Responsibility Using
Vectors: AIM 5-5-6
Prompt compliance with headings and altitudes
Challenge any perception of incorrect headings or altitudes.
Advises ATC if a vector would cause FAR violation
Terrain and traffic are pilot’s responsibility.
ATC Responsibility Giving Vectors
For noise abatement
When pilot requests
IFR planes at or above MVAs
VFR planes at any altitude or as assigned. "Maintain VFR, separation not
Approach by Vectors
Do not repeat everything. ...cleared for approach is enough.
Important item: Cleared for approach is NOT, repeat NOT, a clearance to descend
below any altitude shown on the plate.
ATC position given is only informational and need not be repeated.
ATC turn heading is advisory and need not be repeated or even followed if
pilot judgment suggest a better alternative.
ATC altitude is usually present altitude which need not be repeated. An
altitude restriction should be repeated.
ATC reporting requirement should be acknowledged.
Duty of pilot is to fly approach and acknowledge the clearance with any
restrictions or requirements given by ATC.
Clearance usually gives a fix, crossing altitude, and approach clearance.
Acknowledge only that you have the clearance,
only if you are familiar
with the fix, altitude, and approach.
Approaches can only be entered via radar vectors or by use of a procedure.
Course reversals can be made by a procedure turn or by a holding pattern.
Sometimes both occur on the same plate.
Only by reading the plate carefully can you determine if the hold is also a
course reversal procedure. A plan view in bold line tells you yes.
Advise ATC that you will descend in the hold to allow reasonable descent on
leaving the hold. Extension of the hold is limited to one minute but this can be
done at 200 knots.
When ATC tells you to hold at a five-letter fix, to hold in a cardinal
direction, or to hold on a radial, draw the hold and then decide how you are
going to turn around. Fly through the fix in every case and then take your pick.
You can always turn outbound and make a course reversal. Asking ATC for a
helping vector will not work on a checkride.
Do not expect to be able to fly a holding arrival if you have not configured
before your arrival and reduced the potential for distractions. Don’t fly
instruments unless you are proficient and current. Get all the ATC help you can
but remember that only you can make the decisions.
Vectors and Not Talking
Think before you talk to reduce excess verbiage
You will know when to talk when you understand the system.
Good controllers know the limits of good pilot performance.
By telling the controller the specifics of your aircraft he can plan
your vectors and approach.
The less you say the more you will get.
Comply with an ATC instruction in a timely manner
Listen to your vector instructions, requiring a 'repeat' messes up
the ATC planning.
Know what to expect for you're outside the marker vector heading.
You don't have time to write down vectors to final.
ATC expects you to turn when so instructed. Turn first, Time, Twist,
Throttle, Talk last
When told to change frequency, comply but don't omit things like the
ATIS or requests.
The approach is a nonstop region of activity.
The en route is a more casual region of activity.
Learn to anticipate what comes next so you will be ready.
Quick accurate vectoring is more an art than a science.
After a time the controller knows the wind correction and gives
The 'approach gate' is one-mile outside the outer marker or 5-miles
from the runway.
Ideally you will be vectored to intercept two-miles outside the FAF.
You will never be vectored inside the FAF.
If you see that a vector is not working, fudge to make it work.
Don't talk about any fudging you do. Check your HI against the
Never fudge on a vector that is for obstacle clearance or separation.
The turn-on heading and clearance works if you get through the gate.
Recognize ATC mistakes and correct them without talking about it.
Instrument flying is a constant pattern of compliance and adjustment.
Small errors are not talked about, big mistakes are.
Give readbacks when in motion after the fact this way your readback
confirms the fact..
Charted Flight Visual Procedures
Charted flight visual procedures are used for noise abatement in radar/VFR
situations. original intent was to speed up arrivals. It is not an instrument
nor a visual approach and does not have a missed approach segment. Not to be
logged as an approach. Missed approaches are VFR go-arounds. Determining factor
Acceptance of visual clearance makes pilot responsible.
Acknowledgment of traffic makes pilot responsible for separation and
If unable to land you must remain VFR until obtaining additional clearance.
Must advise ATC if unable to follow
ATC will clear when pilot has airport or aircraft to follow in sight.
Minimums are 1500' and three miles visibility with the ceiling 500' above
minimum vectoring altitude (1500')
Radar service cancelled when you change to tower(advisory) frequency
PAR (GCA Ground Controlled Approach) Approach Only
at some military fields.
This approach is a highly-skilled, labour intensive system being shut down by
the military. It provides glide slope and azimuth direction where all turns and
descents are at the direction of the radar controller.
On being given the instruction:
"All turns will be standard rate until established on the final approach. Then
they will be made half-standard rate. If radio contact is lost for more than
seconds, contact tower on (frequency) and execute the prescribed missed-approach
Every few seconds or so the final controller will issue course and glidepath
corrections leading to the runway threshold. I was talked down to within 10 feet
of the runway at Travis on a PAR twenty years ago. Great feeling. Once on the
ground you may need taxi assistance.
On such approaches the controller would need to know when you had acquired
visual references such as lights so that you could be cleared to land visually
or to execute the missed approach.
Airport Surveillance Radar
This approach has replaced the PAR in most places with radar.
Controllers are requires to practice these approaches and may be more than
willing to give you a practice approach. The procedure requires that the airport
have the required radar capable of giving heading information. ASR altitudes are
recommended only. On final you will be given range to airport and step down
altitude recommendations for each mile. Altitudes will be higher than for
standard instrument approaches.
#1 Cover up the heading indicator.
#2 Keep aircraft under control.
#3 Do what you are told to do when you are told to do it.
When it is a dark and stormy night and the gyros quit the controller can give
you assistance by means of the turn coordinator. He will tell you to turn at
standard or half-rate turns to the right or left and tell you when to stop turn.
An ASR approach requires that the radar range be reduced which effectively
blows-up the picture size for the controller. Usually an entire scope and
controller is dedicated for an ASR approach. There will be no handoff to the
tower. The radar controller handles the landing clearance, rollout, and advises
when to contact ground. A missed approach will continue with the radar
Visual Descent Points
The non-precision approach contains a death warrant for those who cannot
get the approach elements (ducks) in a row. First, is flying the final approach
course; second, comes doing it in IMC or at night; third, is a visual illusion;
and fourth is getting a visual descent point (VDP). The non-precision approach
usually has a minimum of one-mile visibility. Localizers have 3/4 mile and with
lights it gets down to 1/2 mile.
Proceeding to the threshold at MDA means that you must dive to reach the
thousand-foot markers. This means you will arrive at the runway too fast for a
normal landing. The solution is to figure a VDP and use it by timing. Descend
from the VDP with proper flaps and power configuration for landing only when you
see the runway environment. Personally I use the VDP as a marker for turning
downwind during circle-to-land procedures.
The easiest way to get a quick visual descent point is to use the MDA number and
use the two left digits as the number of seconds to take off the approach time.
Example: Approach time 2 minutes 16 seconds. Approach MDA 420 feet. Take 45
seconds (close enough) off leaves one and on-half minutes for reaching the VDP.
IFR Mountain Approaches
Check the reliability of any navaid before initiating descent
failure to remain on the
centreline could drastically affect the quality of
your navaid signal.
Adverse weather is much worse in the mountains
Microclimates near the airport usually go unreported.
Canyons make their own winds, vortices and drafts. Smooth air is rare.
Day winds flow uphill usually making tailwind landings necessary.
AWOS systems are being installed in mountain passes and at mountain airports.
Mountain flying not recommended unless ceiling 2000 above terrain and
visibility of 15 or more.
Don't go into an airport at night that you have not first flown during the
Daylight mistakes are usually correctable. Night mistakes cause accidents.
If no procedure turn depicted, it is not authorized.
Slow down before the FAF to assure ability to descend.
Once on the approach you are guaranteed separation even without radar.
Hills along the approach course are usually unmarked and always unlighted.
Missed approach points are far before the airport. Slow down so you can get
The MDA allows only enough for a safe missed approach. Any lower the
option may be only to land.
Below the MDA you must provide your own obstacle clearance and avoidance.
There is not natural horizon into mountain airports.
Make sure there is a VASI to give you glide slope guidance but only when you
can see the lights.
Roads often parallel the instrument approach course. Car lights can mislead
you as to runway location.
If you lose the airport below the MDA any turn may impact terrain. You have
run out of options.
Circling No-Nos, Maybes and Must Dos
It is not JUST an IFR descent to a
Circling is an approach at half the usual pattern altitude.
Thirty circling accident per year with over half involving fatalities.
Circling killers are going below minimums, steep turns, descent before on
Intended landing must be on normal glide path without excessive manoeuvring
Do not descent below minimum altitude until visual slope indicator
Do not descend to published minimums if not required to do so by weather.
Visual loss of airport or runway requires a missed.
Prelude to a circling accident is a continued approach into weather below
An improperly set altimeter is another prelude to a circling accident.
Any bank angle in excess of thirty degrees is considered steep.
If you can't keep the airport in view flying a normal sized pattern you are
flying toward an accident.
Pilot ego is a circling killer flying toward an accident.
A late or delayed missed is still another prelude toward an accident.
Keeping the airport in sight in IFR conditions requires realistic training for
A series of steep turns will not salvage a poorly planned approach.
Bank angle has a direct effect on stall speed. Fly a pattern that allows
Refer to FAR 91.175)(c)(3) for runway visual requirements for landing.
On a circling approach do not descend on base below minimums.
Don't drop the gear until on final.
The circling approach in actual conditions is the most dangerous approach.
The circling approach has only 300' obstacle clearance.
If during the circle you must go missed when beyond the MAP, you should
climb and turn toward the
airport. Then initiate the published procedure.
Circle to land is in two parts; first find the airport and then find the
In non-precision approaches you never know when to go from IFR to VFR.
When non-precision approach has only circle-to-land minimums even a straight
in is o.k. The minimums are related to the climb required for the missed
Circling minimums are mandatory when descent gradient for straight-n exceeds
400 feet per mile.
Requirements for Best Training
IFR to VFR transition
Full stop taxi back landings.
Teach hazards of circling approaches in VFR practice
Teach short approach landings as basic circle to land requirement.
1. Radar required
2. Random part must be during enroute phase
3. Conventional transitions must be filed at both ends
4. Must avoid restricted/prohibited and TFRs by three miles.
5. RNAV distance to airport uses the ARP or airport reference point near centre
Transponder Landing System
System pings on transponder frequency/code. Antenna arrays on ground
work with computer to give time of arrival for distance (range) and position
relative to angle of arrival (glideslope). Tracking error is computed and coded
to make localizer/glideslope needles work like regular ILS.
Requires transponder, ILS, com radio(s)
Request TLS code for transponder
Contact TLS operator by radio
TLS will cause ILS needles to go active and ident comes on
OM is operative but artificial giving sound only, no lights
Only one aircraft at a time.
Squawk code is used rather than tail number during communications.
Portable version exists.
System has built in integrity monitor
Not available to Part 91 pilots yet.
Uses of the ADF/NDB
The ADF/NDB will be with us far
longer than will be the
VOR. The radio range of WWII
was essentially an ADF with up to four legs. I practiced them on the Link
Trainer during WWII twenty-five years before I became a pilot.
You can use any radio station
to practice the procedures for the ADF. Interestingly one of the PP
requirements a few years ago was to make a descending spiral over a point. I
taught and practiced this procedure using the ADF. Fly to a radio station
antenna and put the needle on a wing tip and descend while keeping there.
Could be an emergency descent procedure in adverse weather if you know where
the station is. Mine is by a river and a large flat area to the west.
The beauty of the NDB procedure
is the simplicity. No frequency changes. Only one needle to watch. With the
advent of GPS and moving maps it remains the last device I would remove from my
aircraft. You will always know where it is and where you are in relationship
You can locate your time
distance from the station just as you can with the VOR. Put the needle on the
wing tip note the time and keep track of the seconds. Fly at right angles to
that direction until the needle has tracked ten degrees. Note the number of
seconds flown. Say it took 200 seconds. Drop the last zero and fly to the
station. Disregarding wind, it should take 20 minutes to get to the station.
Try it. You'll like it. VOR line of sight limitations not a factor. Hazard is
you must know safe altitude to fly direct. In my area I have a 4000' mountain
to the south east of my station only eight miles away
Using NDB approaches is the
least exact approach you can fly. The accuracy can only be improved if you can
determine the required wind correction. I have missed runways by over a mile
by getting the wrong wind. The minimums for NDB approaches are quite high.
GPS approaches will gradually be renamed as RNAV approaches.
Like driving with cell phone expect increase in head-down GPS caused
IFR access to all airports is now possible if funded.
All information about technology is perishable
No handheld is approved for IFR
Make and model of GPS determines what is possible
The pilot is the weak link in full GPS utilization
GPS does not give you cross radials for location
GPS sequences waypoints as they occur in order.
GPS requires manual suspension of sequence if interrupted ---Worst case
scenario is break in waypoint sequence down low.
Actual IFR GPS requires
proficiency of the highest order ---GPS use magnetic course adjusted from true
course to give great circle track
Distance from station affects the sensitivity of the course deviation needle
in VOR or LOC
GPS fakes this sensitivity this an en route mode -+5nm, at 30 miles terminal
+1nm and at 2 miles .3nm
Older nav systems will not be gone until after all the present satellites are
replaced after 2011
The WAAS system may be used as primary means of navigation
Emergency use of a GPS handheld receiver is an emergency out if needed.
How GPS Came to Be
In 1970s U.S. Military developed this all purpose navigational
First satellite launch in 1978 fully operational in 1995 with 24 satellites
It is the antenna system of the handheld GPS that affects its reliability
GPS satellite outages are NOTAMed on DUAT Using GPS ---Minimum of four
satellites are required for three-dimensional position including your altitude
A new GPS takes nearly 15 minutes to download the required almanac and
ephemeris data required.
A GPS measures the time it takes a specific located satellite signal to get
to your receiver
Accuracy of GPS is based on probability down to 99.99 percent within 300
meters, 95-percent for 100m
Comparative accuracy, ILS 15-30’, WAAS20-30’, VOR/DME 200/600’, LORAN 500’
GPS is least accurate in altitude but biggest problem is the integrity of the
Latest GPS models are not required to follow any standard of procedure or
terminology to operate.
GPS can be easily jammed but WAAS and LAAS offers some protection
over 25-mile areas of airports
Ground stations monitor satellites and correct errors with differential
Third generation WAAS systems and receivers use embedded signals to create a
local satellite signal
Older GPS will work but WAAS capable will have reliability and six-second
warning of lost signal
No other equipment is required for a WAAS approach
As of 10/04 there was only ONE WAAS approach available with more to come
IFR En Route GPS
Requires radar contact if IFR but not as sole means of navigation IFR
En route plus GPS approaches connected to basic navs via switch confusing
GPS will arm approach capability when within 30 miles of airport using
Two miles outside the FAF the scale changes to the approach-active mode
New GPS have VTF feature to allow vector to final before activating
The approach GPS will not function if a satellite is disabled ---Approaches
can be added on to a route or STAR IFR Databases
28-day cycle where receiver will not lock out out-of-date approaches—pilot
Database updating progressing from rear cards to front cards to burned on
computer and uploaded direct
Cost up to $700 annually, failure to have charts and plates could violate FARs
Flying the GPS
Waypoints must be flown exactly as sequenced in database ---Decide
whether to fly vectors and traditional or only GPS since mixing may be a
Land or circle to land are options to failure execute missed approach
The ‘hold’ function stops autosequencing until restarted on intercepting
final approach course
Recommended on overlay approaches to use the GPS only as a backup
Block autosequencing when a procedure turn is required ---NoPT approaches can
be flown directly with GPS autosequencing
2nd Generation approaches use the T-shape arrivals without course reversal
GPS approaches use holding patterns rather than procedure turns for course
IFR GPS can substitute for VOR, ADF and DME if fix is in database
You cannot use the GPS for ADF substitute unless you also have an ADF
Using GPS as DME may confuse countup/countdown depending on waypoint
IFR GPS have RAIM with a different level for all three regions of IFR flight
RAIM gives integrity warnings within 30-seconds, 10 seconds
On approach and RAIM occurs fly missed approach procedure
RAIM for an approach cannot be activated without the local altimeter setting
-Selecting wrong IAF
Selecting wrong approach function
Beginning descent at approach active annunciator light ---Confusion in
activating autosequencing outside FAF - Confusion when GPS changes scale
outside the FAF ---Caution in selection of MAHWP button at wrong time or place
---When in doubt check a chart.
Modes are APCH,OBS, CURSOR, and LEG
---OBS is for the missed, procedure turns and holding
GPS starts in LEG mode such as ‘direct to’
IFR GPS allows sequencing of waypoints as required for IFR procedures
Waypoint inserts and cancellations are an additional IFR procedure
requirement s met in the cursor mode
The cursor mode allows you to scroll through the flight plan to m