Usually, the question's animation breaks each applicant's trance. Examiners want to hear instrument rating airplane applicants reply, of course, 45 degrees of bank. Too often examiners hear something else. Usually, if the answer is wrong, it is because the applicant's mind is locked on three words that his or her flight instructor has repeated again and again, mantra-like: standard-rate turn. Standard rate turn. And again, "standard rate turn." Some applicants become adamant in this, and most examiners have heard, "We are never supposed to bank beyond a standard rate turn when in the clouds." I suspect that only the most uncommon of instrument flight instructors has ever given that as an edict, for life and the FAA decree otherwise.
The Practical Test Standards (PTS) calls for examiners to test applicants' skill in flying a steep turn during the practical test. For airplanes, this means 45 degrees of bank; for helicopters, a more benign 30 degrees will suffice. The reasons can vary widely for a pilot to actually use so draconian a bank when deprived of visual reference, and it's extremely rare for so heart-pounding a reason as my favorite scenario details. But there are times when pilots need such a skill in the enfolding gray. More likely than my scenario, weather-induced turbulence is one factor that pilots battle repeatedly during their careers. Fervid turbulence penetrated by inept attention produces steep banks.
When instrument pilots discuss turns, any beyond standard rate they consider to be steep. For this discussion, the PTS-mandated 45 degrees is the target, because examiners long to hear applicants discuss the pronounced aerodynamic changes that such banks bring. Stall speeds become paramount. Still, examiners rarely see instrument rating applicants stall when testing on steep turns. Instead, altitude excursions predominate. Since instrument flying still has novelty about it by the time we take our checkrides, our minds are locked on the nuts and bolts of instrument interpretation. Entering a 45-degree banked turn reduces the vertical lift component to the point that pilots must either consciously or instinctively correct for the loss. Few are at the "instinctive" stage.
The FAA wants this area tested because poor pitch adjustment leads to increasingly strong elevator pressures, and the loss of vertical lift and increased wing loading ultimately degrades into a diving spiral. Naturally, this is bad in instrument meteorological conditions (IMC). The PTS allows for not more than 100 feet of altitude change during the steep turn, so the needed skill in instrument cross-check, interpretation, and response increases in proportion to how steeply, and the rate at which, one banks.
While testing, salvation is not assured by entering the steep turn slowly any more than an instant roll to 45 degrees. Too slow a rate of roll into such a turn almost always sends the airplane into a climb, sometimes beyond the allowed 100 feet. Again, that vertical lift component begs the pilot to fly the wing, and attitude control wins the day. Even when pilots bank so leisurely that the airplane wants to climb, by the time the attitude indicator announces the mandated 45 degrees, loss of vertical component becomes overriding and the airplane descends. Or falls, if one ignores the pitch attitude. Or plummets, if the power has been mishandled along with other aspects of attitude instrument flying. By entering the bank too slowly, perhaps all a pilot might gain is avoiding vertigo induced by physiological factors which are yet another aspect of steep turns.
Entering the bank fighter-pilot style - rolling crisply from 0 to 45 degrees of bank in less than a second - may seem to avoid lift vector problems, but it can induce vertigo because of the sudden attitude change to the Eustachian tubes.
So, during your checkride, what should you do? The PTS does not specify the rate of roll, so student and instructor should practice the steep turn on occasion during the entire instrument training. Too often examiners find that their applicant's only steep-turn training occurred during the first few hours of instrument flight training. Then, the new skill lies dormant as student/instructor teams concentrate on instrument approach procedures. As you prepare for your instrument checkride, remember that Area of Operation IV still includes Task F.
In fact, the Note to Area of Operation IV specifies that Task F shall be performed using all available instruments, so your examiner should not attempt to cover gyroscopic (or any other) instruments during this task. Over the years, some rogue examiners have tried to justify covering required instruments by claiming that one day a pilot may need to conduct a steep turn without having gyroscopic instruments available. In a perfect example of how one PTS task touches another, it is at this point (loss of gyro instruments in IMC) that a prudent pilot should elect to terminate the flight in IMC in a timely manner. The mere fact that a pilot's planning gave no hint that a steep turn might be needed during the flight is no assurance that the need for a steep turn will not be encountered. How often does a planned instrument flight include one? Attempting steep turns or combating turbulence-induced unusual attitudes without the gyro instruments, when unnecessary, demonstrates a horrifying lack of judgment. Some events, though rare, necessitate a steep turn.
Once an applicant has entered a steep turn, the PTS mandates that an applicant perform the turn for either 180 or 360 degrees. During this time, on your checkride you must maintain the bank within plus or minus 5 degrees of the target bank angle. This means that you must be familiar with the face of the attitude indicator. While it is not frequent, most pilot examiners have had applicants enter 30 degrees of bank, believing the mark on the attitude gyro meant 45 degrees. This is disqualifying, because the aircraft never reaches the specified bank. Even worse are those rare applicants who misread the attitude instrument's face, taking the 60-degree mark to mean 45 degrees. In many airplanes, the directional gyro begins spinning shortly before reaching 60 degrees of bank. Beyond that bank angle, most instrument-capable airplanes will have transgressed their airworthiness limitations, unless they are certified as aerobatic. (The FAA has not yet created an instrument aerobatic rating. And don't hold your breath waiting for one!)
Maintaining the proper pitch/power/trim configuration for a steep turn is not difficult. Too often applicants make it so. If you perform a steep turn solely by instrument reference, how long will you be in that turn? For so short a time, is it necessary to change the trim setting? Some airplanes require it, but these are not ones commonly used on checkrides. Applicants often trim their way out of standards during the steep turn, partly because of the time involved for aerodynamics to catch up to the pilot's trim inputs, partly because of the vertigo that turning the head to find the trim control might induce, and partly because of the distraction from interpreting and responding to the instrument panel. Be wary of trim during steep turns!
Once the turn's completion is imminent, rolling out is as important as the entry. All the factors remain at work during rollout as during entry, and your examiner knows this. It is just that they change chairs, as if in an aeronautical game of musical chairs done to the beat of the slipstream's thrum. Lift vectors return to normal, and roll rates combine with turn rates to confuse the Eustachian tubes. Elevator and power control demand smoothness, for the errors common to standard-rate turns generally apply to steep turns, but steeper banks make these errors more exaggerated, harder to correct. Your rates of entry and recovery must be consistent with your level of proficiency in basic instrument flying, and the FAA considers that at the time of your practical test, your skills are at their peak. That is just the time to take your checkride!
Dave Wilkerson is a designated pilot examiner, writer/photographer, and historian. A commercial pilot, he has been a CFI for 22 years and has given about 2,000 hours of dual instruction.
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