no problem flying

Standardized Controlled IFR Flying
It is not possible to substitute IFR simulation for the experience of actual IFR conditions. Only actual conditions can give you the turbulence, precipitation, wind shear and lighting changes that can cause vertigo. Compounding these conditions will be ATC speed-talk, demands, clearances, inquiries, and requests for readback. Worst of all will be that the controllers who have concocted the clearance are not talking the language of the controllers who direct traffic.

The purpose of IFR training is to produce a pilot who has sufficient skills and competence to fly IFR safely during the refining period of retaining proficiency and actual application of the training. This training rests of several basic but mandatory manoeuvres. The IFR pilot must have automatic control of the aircraft through coordinated turns, stalls and patterns. The fundamental skills of IFR are straight level flight, turns, airspeed climbs and descents, a light or hands-off yoke touch, and throttle movement.

A weakness in any of these areas will compound any procedure problems. Early mastery of these basics will reduce training time in the long run. If you can't fly using the gauges without thinking about it, you won't have the ability to think about all the other things involved in navigation and communication.

Control instruments

Primary instruments are always the ones with the numbers. For straight and level it is the altimeter for pitch, the heading indicator for bank and the tachometer for power. When an airspeed is assigned then the ias is primary for power as the throttle is adjusted to maintain airspeed. Ability to maintain heading and altitude over a distance is a basic requirement.

The proficient pilot knows by sound the present power setting and airspeed. He knows how much change is required to go to another performance situation. He knows by both feel and sound the change made. Then he confirms by looking at the control instruments. I have found that most pilots tend to over-control when using power.

Performance instruments

Airspeed indicator
Turn coordinator
Directional gyro
Vertical speed indicator

1. Know your power settings and aircraft configurations.

2. Performance instruments are your means of determining the effect of control input.

Airspeed is set with power.
Reset your HI and set approach configuration before descending.
Descent is initiated by power reduction. Know the reference descent rate and bracket it with power changes.

3. All turns related to flying are pre-selected on the HI but entering and stopping the turn is with the AI.

Minor corrections can be done with the rudder.
Power, Power Changes and Trim

Once you have mastered the power, power change and trim required for two climb speeds, two descent speeds, and at least two level speeds, using only the AI, you are ready go on to...

Redirect the aircraft:
1. Set power and AI (attitude), trim as required
2. The trend of movement is shown on the turn coordinator and the VSI.
3. Check trend. If unacceptable redo the AI. Check the numbers information. FAA Primary instruments have numbers on them. They allow you to tune your performance.
4. Fine trim for hands off. This must be done without error or hesitation. If a problem exists practice aircraft control basics.
5. Look for meaningful information. Set the AI, check the trend then read the numbers

You can practice constant headings first by constant airspeed and them by constant altitude. The variables are made through power changes from full to idle. This requires great attention to the rudder, elevator and throttle coordination. For constant airspeed the hands move in opposite directions to get pitch and power. Initiate the climb until stabilized then set up the descent. Repeat until you can anticipate the coordination required to keep constant airspeed.

Level cruise

A constant altitude with power and pitch to obtain cruise speed.
Power for airspeed
At desired speed, lean for economy
Frequent full power flight is good for engine
Set AI, check TC and VSI for trend
Fine tune: Alt for pitch, HI for bank, Tach for power
At level cruise the altimeter is primary pitch.

Airspeed, AI, altimeter and VSI are affected by elevator and throttle. Any change in power only results in change in airspeed or altitude. Check altitude before adjusting airspeed by power. Changes in straight and level airspeeds require adjustment of pitch, power, and (bank) rudder.

Approach cruise

Fine tune: Speed at top of white arc, Vfe
Reduced airspeed that may be best endurance
1/2 bar high on AI
Set AI, check TC and VSI for trend
Alt for pitch, HI for bank, power for airspeed.

Level to Climbing Turn
(As in a missed approach)
1. -- Airspeed for pitch, TC for bank, Tach for power
2. --AI set, then power (full), airspeed and turn coordinator (TC)
3. --Check trend. If unacceptable redo #1.
If acceptable go to #2 & #3.
4. --Check the numbers information
Bank information is AI/TC or HI for constant heading (wings level)
Pitch information is airspeed/power, altimeter, or VSI
Power information is tachometer or airspeed

The turn requires that the altimeter be used for pitch and the turn coordinator for bank. Tachometer is primary for power. As before, required airspeed is controlled by power adjustments. The TC should be calibrated by doing timed turns. The rate of turn is based on airspeed and angle of bank. Turn rate decreases with reduced angle of bank and an increase of airspeed. Standard rate turns can be figured by using 10% of your ias and adding five. Limit your angle of bank to the angle of small heading changes. Use five degrees of bank for five degrees of turn. Use the standard 1/2 angle lead in rolling out to a heading.

Steep Turn

Altimeter for pitch,
Attitude Indicator for bank,
Tach for power
Lock the AI centre dot

Cruise Descent

No flaps since G-load is set lower
Speed limited by ATC, Vne, Vno, or Va
One bar low on HI for 500 fpm descent
VSI for pitch, HI/TC for bank, airspeed POH
Lock the AI in pitch.

Slow Cruise Descent

Full C.H. and 1500 rpm
Extend Gear and partial flaps
Less than 1/2 bar down on AI
Power for airspeed at or just below Vfe
Prepare for go-around or landing

Chop/Drop descent
Airspeed/VSI for pitch, TC for bank, tach for power. Lock the AI in pitch.

Chop and Drop vs. Descent Profile
There is a conflict of procedures in the use of step-down non-precision approach procedures and the advent of new technology that allows a descent profile to be flown. What has come about is a secondary acceptable method of flying the approach by hand flying the descent profile because it seems to afford some pilots the
sense of a more controlled flight down to the MDA

The vertical path angle and descent rate tables of the Jepp plates give a stabilized approach preferred by large aircraft because of its similarity to an electronic glide slope. This minimizes the required descent rate, eases the workload and stabilizes the approach configuration. A few such approaches in VFR conditions using the GPS as a backup should help any pilot to make a knowledgeable choice.

VSI for pitch, HI for bank, airspeed for power
Lock the AI in pitch

Level bank
During a level bank the compass, HI, turn coordinator and AI, four instruments in all move. If you don't like what's happening to any of them, adjust the AI

Level to Descent
The type of aircraft makes a difference in how descents are initiated. In fixed gear aircraft you can get 5 for 5 almost every time. 500 fpm for 500 rpm. This works if you maintain the same speed in the descent as you had in level flight. If you are going to descend at a slower speed than the level speed, it may be best to slow and trim for the descent speed while in level flight and then use the five for five descent parameter.

Retractables have vastly differing drag coefficients with the gear down which will necessitate developing a level to descent chart. It is a waste of time to try to fly an approach without having in your memory bank exactly how to attain the speed and descent rate standard for your aircraft. The more 'constants' you have developed for flying the aircraft the less likely will flying the aircraft be part of the problem.

Constant airspeed/power uses the airspeed for pitch, the HI or TC for bank, and tach for power. Lead altitude by 10% of your rate of climb or descent. A constant airspeed climb/descent while turning you decrease pitch with increase of bank angle. Airspeed will be constant but descent rate will increase and climb rate will decrease. Pitch, bank and power are all changed.

Descent to level
If you know that you will be levelling off shortly after initiating a descent as though descending from the FAF to a circle to land altitude, you would be best not to change the trim. Make the descent by power reduction only in fixed gear aircraft or in retractables that have their gear down before the FAF. If the gear/flaps are not down at the FAF use the gear/flaps to initiate the descent and plan to adjust power and trim at the levelling altitude.

Cruise to Approach
In fixed gear the change in speed is initiated with an immediate power reduction to a predetermined setting. You must know and have charted the power setting that will give a given approach speed. Trim off pressure slowly while holding heading and altitude. Keep track of the trim setting.

The constant altitude requires a sequenced movement of both hands in the same direction. This exercise will require trim adjustments. Power is changed from full to idle and back again. Rudder applications must be anticipated to hold constant heading. Using power go from full power and back to idle several times.

The process may be made faster by initially taking off more power. Application of trim must then be quicker but to a known setting. Pre-determined power must be brought in just as speed reaches approach speed. Missing this point of power application will exacerbate problems associated with attaining approach speed. Retractables should include dropping the gear and any flap application as a part of the speed change to approach speed. Variations of just when to do what will vary from aircraft to aircraft.

Best Angle Climb, Vx

3-bar high on AI
Maximum power
Speed increases with altitude
About 5-10 knots below Vy
(Minimum sink speed on engine failure)
Lock AI in pitch

Best Rate Climb

2+ bar nose high on AI
Maximum power
Fastest rate of climb
Caution on traffic avoidance and engine heat.
Lock AI in pitch

Cruise Climb

Constant airspeed or constant vertical speed
One-bar nose high - Locked
Better speed, visibility, and cooling
Advise ATC if not 500 fpm

Initially, we will discuss the climb. Any aircraft in a climb has an inherent left turning tendency. The steeper the climb the greater the tendency. The amount of right rudder required, therefore, will vary. This is strictly a feel skill augmented by watching the 'ball'.

The best-angle of climb Vx, as might be required to meet a specific gradient on an approach plate, uses full power and near a three-bar AI climb. Partial flaps may be specified in the POH. Vx speed increases with altitude and usually is less than 10 knots of Vy speed. Vx speed is a good emergency, engine out, glide speed.

Best rate at gross in a C-172 is 78 knots with best angle about 65 knots. This will be near a 2-bar AI climb. Some IFR procedures require different climb rates per mile. Since climb is always at full power we need to determine and fix in our skill envelope the trim required to climb at both 78 and 65 knots. Mark the trim setting as for a Vy takeoff climb on your aircraft. Practice coordinating the trim movement with your yoke and rudder control of the attitude indicator until you can go from one speed to the other with a minimum of oscillation of airspeed and attitude. Different loading may require slightly different settings but once the technique is perfected for one loading, it adapts readily to changes and even other aircraft.

The C-172 trim setting for a 60 knot full flap landing will be very close to the setting required for Vy climb. From level cruise to a Vy climb raise the nose, apply full power, trim one full ‘top button to the bottom’ and you will be very close to hands-off Vy climb.

Cruise climb provides more distance, better cooling, and better visibility. ATC expects 500 fpm climb rates so be sure to advise ATC if you plan to climb at less than that.

Levelling Off
After the climb we usually level off. An old saying among pilots is, "How long does it take a student pilot to level off?" Thirty-five hours is the answer.

If you reduce the power in time and to the right amount the speed will remain at cruise. The trim will be correctly set perhaps with only the slightest of adjustment. It is when you don't level off smoothly with every setting of attitude, power, and trim set in anticipation of aircraft performance that IFR flight problems occur. For me, the best clue is sound. Every performance parameter or change has a sound. Learn the sound of your airplane. Sound sensitivity will transfer from aircraft to aircraft just as it does from car to car.

You should keep your hand on the throttle. Use your forefinger as a lock, a measure and control of the throttle. This is particularly important in the C-172. The power to weight ratio of the 172 is such that deceleration and sag is quite abrupt while acceleration may take several minutes if too little excess power is applied. Once the required power settings are known they must be adjusted for altitude and temperature. Up to 200 rpm difference will exist between hot and cold day operations. Numerous small changes of power will be required in most flight conditions but particularly on approach. Keep power reductions small but increases should be of 200 rpm or more soon to be followed by reduction of excess power. Learn the sound of aircraft power as well as performance. Any change in constant power necessitates trim adjustment. Plan accordingly.

The student should know for levelling off from a climb at Vy will require a certain amount of anticipation, a certain amount of trim, a certain amount of acceleration, changing amounts of yoke pressure, a power adjustment, changing sounds and some fine tuning. The trick is to put the aircraft into the desired attitude and leave/keep it there. The reason instrument flying becomes easier is because the pilot selects an attitude and leaves it there. In order to fly instruments well, you learn to note very small indications and very small trends. Doing this while levelling off is just a beginning.

Levelling off from Vx will differ from that of Vy. Levelling off requires anticipation of what the aircraft is going to do. Due to the low power to weight ratio of the C-172 you must anticipate the effect of a longer and slow acceleration. Initially lower the nose to catch the altimeter needle at altitude using the attitude indicator as primary aid. Make your initial rough trim movement that your experience and practice has shown will be about right. If you have not trimmed enough it will begin to climb during acceleration. Correctly trimmed the nose will want to drop. You must anticipate and gradually relax any back pressure against the trim's effort to lower the nose until the increase in airspeed releases the down pressure. The 172 may take a while to gain speed but once it has reached its normal cruise speed reduce the power to 2450 rpm. Don't be satisfied to fly 50' off altitude even if you are holding it there.

Practice levelling off from Vx and Vy until you can anticipate the attitude, performance and settings required for the transition from climb to level. Mark the trim setting. Learn the sound of level cruise. Do this until you can level off and hold heading. Do this until it becomes automatic not just within 100 feet but right on altitude and heading. You must become so proficient that flying the plane will not get into the way of flying a departure or an approach.

If you level off below altitude the period of hand flying and acceleration becomes prolonged. This is just another area where flying is capable of interfering with IFR procedures. This is just the time that ATC will chose to amend a clearance or such. Everything comes unglued. This usually results in corrections that will require multiple adjustments. It is easier to do it right the first time.

You may not select the correct level attitude on the attitude indicator resulting in a climb above your desired altitude. You have two options. Lower the nose and dive down to altitude. This results in a speed increase which will result in another gain in altitude unless the power is reduced. At the higher speed the trim is no longer correct for level flight. The result is a series of altitude and airspeed oscillations until finally the desired initial settings are acquired. You will go up and down a hundred feet or so with changes in airspeed, attitude, power and trim. Essentially the same effect is created if the power is left in too long so that excess speed is acquired. Likewise, if too little trim is initially applied. These are typically flight indications of a pilot who has not acquired basic skills.

Level Cruise to Low Cruise
After levelling off at cruise we may need to hold level while slowing down to say holding speed. First reduce your power to a predetermined setting (1700 rpm) that you know will work. As the aircraft slows apply back pressure to hold altitude while trimming quickly one turn down (nose up) smoothly to the amount that you know will work. Quickly increase power to 2200 rpm before speed gets below 90 kts. If you don't know what works, repeat these changes until you do know. If you have avoided any oscillation of altitude this should be a very smooth transition. The resulting configuration will show the AI about 1/2 bar high. Otherwise, practice it until it is a very smooth transition.

Descent, depending on the situation may be made from cruise or from approach speed. A smooth descent is about level on the AI for 500 fpm to 1/2 bar low for greater than 500 fpm.. Work on determining the initial power settings that are required for both 500' and 1000' per minute descents from both airspeeds. Descents of 1000' and the last 1000' of any greater change are made at 500 fpm. The basic is five for five. Low cruise at 2200 rpm reduced to 1700 rpm will approximate 500 fpm descent without change in trim. It is better to set up your descents by reduction of power and not change trim. This is under the assumption that application of power will give level flight at the appropriate speed. This is especially true if the speed has been held during descent. Practice descents and these airspeeds until you determine the power reductions that give the desired performance. Again, the performance parameters of the descent and recovery must be practiced until smooth.

Your airspeed for descent is somewhat limited by the Vne redline, Vno structural meeting of green and yellow, and Va manoeuvring in turbulence speed in the POH. Do not extend flaps at any of these speeds since allowable G-load is much lower. Always use some power and carburettor heat for descents to keep the manifold warm.

Level from Descent
Levelling off from a descent is somewhat different. If the descent is only accomplished by a power reduction without speed change, application of power will give you "level". From 1700 rpm to 2200 rpm. If trim is used or a change in speed is called for, it is important to keep in mind the amount of trim change involved so that it can be reset for level later. Speed changes must then be anticipated by power settings.

Cruise Descent
Cruise descent to a destination altitude at 500 fpm can be figures by multiplying your altitude in thousands less destination altitude by two to get the descent time in minutes. Multiply by 4 if descent is at 250 fpm.

Current MSL altitude 8000'
Destination altitude 1000'
Difference is 7000'.

@ 500 fpm 7 x 2 = 14 minutes descent time.

@ 250 fpm 7 x 4 = 28 minutes descent time.

The last element of basic IFR flying is the turn. Climbs, descents and level flight will either require a constant heading or a turn to an assigned heading. Initially work on maintaining a constant heading. A constant heading is best assured if the wings are kept level. Use the attitude indicator. If the heading is changed or changing, one wing must be low. In climbs rudder application may be required to keep wings level.

An IFR turn is usually shallow compared to a VFR turn. The VFR habits of yoke pressure in the bank causes over control when IFR. No power change should be made in level IFR turns. Pilots who are frequent VFR pilots will inadvertently climb in VFR turns. Lead your desired heading by 1/2 the angle of bank. Every turn requires a lowered wing and a slight loss of lift. Even the lightest back pressure of one finger in an IFR bank must be countered with the thumb pressure when levelling the wings. Otherwise, a pop-up of some degree will occur.

If you are doing a timed turn with the compass, use a sweep second hand, set the ADF to your initial heading as an aid. Do your figuring before you start the turn. It is much easier to relate sweep hand to turning of HI. Digital watches make relating the time to the turn more difficult.

Stop the turn by reference to the top index marker on the attitude indicator. The most common error of any small turn is to reverse the turn back to where you started as opposed to stopping the turn and holding it. Making the turn with the rudder seems to focus your attention to the AI better on recovery. Larger turns are subject to same error to a lesser degree. If you have a heading bug use it. If you don't, use your mouth (say aloud) to keep the required heading actively in mind.

You must learn the angle of bank on the attitude indicator which represents the standard rate turn on the turn coordinator for your IFR airspeeds. The angle of bank for any airspeed can be determined by dropping the last digit of the airspeed; Divide by 2 and add back to first dividend.

An airspeed of 100 knots would show:
100 drop the last 0 = 10.
Divide 10 by 2 = 5
Add back the 10 = 15 degrees of bank.

Work on your skill in making small heading changes using only the rudder since those are most often required. Use half standard angle and a count system for the turn itself. For heading changes of less than 20 degrees, use banks of 5 degrees. For heading changes of less than 10 degrees, use rudder alone.

To attempt to fly IFR approaches without the required basic flying skills is both frustrating and self defeating. There is little or no value in flying repeated approaches without success. This is even more so if the absence of basic required flying skills are the major cause. If there are any required elements in IFR flying it must be the holding of altitude and heading. Of the two, altitude is most easily acquired and retained. Heading holding requires a rigid arm and wrist with a feather touch on the yoke. Better yet, use the rudder to hold or change approach headings once established.

For practice you might try flying a rectangle at altitude using just the rudder and no yoke to execute standard rate turns. Then try flying a pattern with descent using just rudder and power and standard rate turns. Expect the ball not to be "pretty" during rudder only manoeuvres. Mastery is when you can fly an approach with rudder and power.

Partial Panel
As opportunities present themselves the unusual attitude, no-gyro approach, and inoperative equipment situations should become a regular part of the training program. Every flight should revisit some technique that is part of the PTS. If you have a "heading bug", set it for every heading. Set it for the ILS prior to interception. HSI equipped planes should always have HSI set to correct heading even though the HSI will correct for reverse sensing. One of the best partial panel exercises is to fly Single VOR using a Hand-held radio.

While rocking and rolling can bounce you around you will not feel the pressures of a steep turn or abrupt change in altitude. The gradual failure of a gyro that disorients a pilot can be recovered in a simulator but recovery is far less likely to be successful in flight. A disoriented pilot is more likely to remain disoriented. Avoiding loss of control in the first place is the defining element of successful flight with malfunctioning instruments. You must recognize that you are dealing with a malfunction. You must exercise the will power needed to ignore, ideally cover, the failed instrument and concentrate on those instruments that are working.

Actually partial panel flying is relatively easy once you have isolated the problem. One very desirable practice exercise would be maintaining control in turbulence using the turn coordinator. The symbolic airplane of the AI and the turn coordinator turn in opposite directions. You must practice with the TC to make sure you won't become confused. It is of interest that nearly all loss of control situations occur in a spiral dive with increasing airspeed. Seems to indicate that most anyone would be better off attempting to climb…after the wings are level.

A pilot filing IFR in busy terminal areas should expect to be routed differently from the filed or shortest route. Look up the preferred routes but still expect changes due to your aircraft performance. Re-routing will usually lengthen your flight and reduce your reserves. Be prepared to indicate to ATC this as their changes affect your time en route and fuel reserves. Never pass up a chance to fill the tanks and stay high if fuel becomes a problem.

1. Radio and Intercom
2. Head down
3. Unusual/Unexpected
4. Traffic search

It is the unexpected distraction that is most difficult to ignore. Any distraction that requires multiple responses is more difficult to accept and correct for. Distractions that require you to reference to an unfamiliar sectional or chart are more likely to require extended concentration. Any inattention from the instruments while hand flying of over three seconds is likely to mean the aircraft will deviate somewhat in heading and pitch.

It takes considerable discipline to break away from a distraction critical to flight safety. Still, flying the aircraft is the most important duty of the pilot. In actual IFR conditions any time spent away from the instruments makes you subject to vertigo. The temptation to abruptly move the controls can be overwhelming.

Conversation, either with ATC or in the cockpit is likely to become a major distraction when a high workload situation exists. Minimize conversation when you are busy. You cannot monitor the flight if your head is down. Practice holding papers up in the cockpit so you can see outside or the instruments over the top of documents. Get your critical approach information well ahead of time; plan for getting the ATIS/AWOS well before you arrive. A disproportionate number of incidents or accidents occur while taxiing. It is best; (mandatory) to suspend unrelated activities while taxiing.

In flight, it is the turn that is most susceptible to distraction. Do not change frequencies, write, or otherwise allow other activities to interfere with a turn. When you must do two tasks at one time, concentrate on the instruments and do a bit of each task at a time. Any interruption is a strong warning that your workload is building to where things may begin to unravel. Don't let flying the plane become a part of the problem.

Low-Visibility Takeoff
The most obvious risk is loss of aircraft control during and shortly after takeoff. Control can be lost during ground acceleration or in the transition from seeing the ground and entering MIC. You do not have any prep-period for the instantaneous change. The increasing acceleration and climb attitude during the takeoff has dramatic effects on the pilot's inner ear so concentration on initial heading and climb attitude are essential. The entire takeoff and climb should/must be on the gauges. The primary instrument, initially and throughout is the heading indicator that has been set for runway heading while holding on the centre line.

The next immediate risk is loss of power. Even if you know the area, low-visibility blinds you and trusting to blind luck is not a good choice. It is for these reasons that the airline minimums of one-mile visibility are good minimums for the Part 91 pilot, too. Should a power loss occur you have little option beyond maintaining straight ahead control. This particular takeoff is far more dangerous for mulit-engine aircraft than for single engine.

Preping IFR Landings
1. Slow and trim before you start down
2. Retractable gear to slow down or for descent.
3. Retrim for configuration changes
4. Runway in sight with landing assured signals final configuration change.

1. Have a contingency plan
2. A successful escape from icing one time has no relevance for the next.
3. Known icing exists if forecast or reported.
4. Aircraft not certified for flight into known icing must not enter icing conditions.

Hand-Flying in Marginal Conditions
Once you become dependent on an autopilot you will find that reversion back to hand flying skills in moderately severe weather seem to lack the precision flying, power and airspeed control, delicate changes and processing information at rates that validate your experience and confidence.

You can regain your hand-flying skills by flying a monitored approach. One pilot flying and the other pilot giving the altitude callouts as well as the go-around.

Circling approaches very often turn you into runways that have neither an approach nor a missed procedure. Airlines avoid making circling approaches and contact approaches.

When things get crowded ask for a contact approach. A contact approach is a radar vector to an airport and a runway requiring ground contact with one-mile visibility and clear of clouds.

The Art of Anticipation

Even more so that VFR, IFR requires knowing and anticipation of what lies ahead.
The key to remembering and anticipating is a USED checklist regardless of type.
While checklist may be the first word on the list, the last words are "checklist complete"
Oral use of checklists are best preventive of skipping or forgetting.
IFR anticipation requires pilot to be at least two steps ahead of what is happening now.
T-list is Turn, time, tune, throttle, twist, talk, track, Threat
A 'threat' is something that must be expected and acted upon in a series of stages.
You have a war like situation that is constantly changing in frequency and intensity.
First is a 'set' as in get ready, get set. It is the time, place or ATC 'set' to begin. (Place includes altitude)
Failure to think, know, and act compounds the threat involved because there is a second threat ahead.
In IFR the sequence of threats can be predicted, anticipated and planned for. Doing so requires training.
The 'threats' are always very close to the same each time so experience over the route helps in all ways.
Time 'threats' can be based on arrival, departure, altitude and duration.
Time 'threats' usually start a new chain of 'threats' as does some place and altitude 'threats'.
No sooner is one 'threat' completed that the next 'threat' must be identified and the next, and so on.
Radio calls are the 'turbulence' of cockpit organization, expected but startling, garbled but required.
ATC radio calls are used by the controller to organize his 'threats' to make the system work.
More often than not the ATC system runs itself for its convenience more than for that of the user.

Playing the IFR Game

Know the weather
On departure into overcast, request climb to VFR on Top
You are not VFR until 1000 feet above the under-cast.. Cancel when VFR
On arrival above overcast request a descent to VFR on the Bottom.
You are not VFR until 500 feet below the overcast. Cancel when VFR.
VFR/IFR or IFR/VFR composite flight plans requires use of FSS to activate and cancel VFR parts.
When VFR, you cannot get an IFR clearance if you are below minimum enroute altitude (MEA)
Don't use a composite flight plan if you expect to request IFR direct.
When expecting an extended IFR ground hold, request VFR departure. Get clearance when airborne.
ATC may give computer a departure message (DM) so system knows you're flying though not IFR.
You are using good weather to get into the IFR system.
Once at assigned altitude and level you are at a 'hard' altitude. Stay there.
Flow restrictions may prevent any IFR/VFR combination from working.
Pre-file an IFR plan far down the route. Plan to open the IFR plan at the end of the VFR flight.
Select your IFR pick-up at the beginning of where a Centre begins and get the frequency ahead of time.
Pop-up, VFR on Top and VFR on the Bottom clearances begin with a clearance limit.
If you can see and expect to keep seeing traffic you can negotiate closer ATC separation.
Don't accept a visual separation you will not be able to keep.
On accepting visual separation by saying, "I have traffic", you are responsible unless you can hand it back
Don't let ATC fly you IFR into weather you can avoid by remaining VFR.
Skirt thunderstorms and avoid icing.
VFR on Top allows you to pick and change VFR altitudes below 18,000 while still on an IFR clearance.
You can select tailwind altitudes, must avoid traffic,
VFR on Top requires you to fly hemispheric rule altitudes, fly exact route, be above IFR MEAs.
When VFR on Top and requesting 'direct' keeps you VFR without navaid limits.

Weather Statistics

90% of aircraft involved in weather related accidents never made a radio call for help.
Weather related accident by light aircraft account for only 3% of the fatal accidents.
90% of weather related accidents do not happen to IFR pilots.