APPENDIX
APPENDIX
ANGLE-OF-ATTACK EVALUATION - PILOT QUESTIONNAIRE
A. Display factors 1, Was the meter face readable at all times?
Pilot (A) Yes.
(Bj Yes.
(C) Yes.
(D) Yes. I wouldhave preferred a vertical meter.
(E) Yes.
(F) Yes.
(G) Yes.
(H) Yes.
2. Did the scale seem adequately expanded?
Pilot (A) Yes.
(B) Yes.
(C) Yes, although the cruise portion is greater than needed.
(D) Yes.
(E) No. Since angle of attack is useless near cruise (low angle of attack), eliminating the right half and doubling the left half would be desirable.
(F) No, not in the cruise portion. Scale was adequate in high-angle-of-attack region.
(G) Yes.
(H) Yes.
Were the markings readily understandable?
3.
Pilot (A) Only after explanation.
(B) Yes.
(C) Yes, after beingprebriefed.
(D) Yes.
(E) Yes.
(F) Yes.
(G) Yes.
(H) Yes, but some simplification may be needed.
Did the horizontal needle deflection cause any confusion?
4.
Pilot (A) No.
(B) No.
(C) No. Itseemednatural.
(D) Yes.Someambiguityrepeatedlythroughouttheflight.
(E) No.
APPENDIX
APPENDIX (F) During the first several approaches, it seemed like there was too much horizontal movement of the needle with no apparent action by the pilot. A t first, because of t h i s , there was a tendency to chase the needle. After the first several approaches, the fluctuations were integrated and there was no further tendency to chase the needle.
( G ) Yes, due to unfamiliarity. Once trimmed the wrong way to bring the needle to a new position.
(H) No, but vertical needle deflection would be more appropriate.
5. Would you have preferred a circular indicator?
Pilot " (A) No preference.
(B) No.
(C) No preference.
(D) Yes, if the needle were nearly horizontal for approach speed range.
(E) Can't say, since I haven't flown a circular one. Suspect I would not have any preference one way or the other.
(F) Yes. I say this because I used the circular indicator in the Navy. Also, with the desired approach angle of attack at the 3 o'clock position, the instrument is easier to interpret.
(G) Not particularly.
(H) No.
6 . Was the location of the meter adequate?
Pilot (A) Yes.
(Bj Yes.
(C) No. For IFR work I would like it below the attitude gyro o r near the top center (like a head-up display) of the panel.
(D) Yes.
(E) Yes.
(Fj Yes.
( G ) OK for temporary test installation but not for actual IFR.
B. Takeoffs, - ". approaches, . and landings 1. Is the takeoff procedure acceptable?
Pilot (A) Procedure not acceptable when using angle of attack only.
(B) No.
(C) Yes, although I feel it's unsafe in high-density traffic; visibility over the nose is nonexistent. The task is acceptable.
(D) [No comment. ] (E) No. In fact it was ridiculous to try to take off on angle of attack alone.
(F) No. I did not feel that the instrument could be interpreted quickly and accurately enough to use for a takeoff.
(G) No. Requires gentle touch and familiarity with aircraft.
(H) Yes.
APPENDIX
APPENDIX 2. Would you suggest a better procedure?
Pilot (A) 1. Use airspeed Vmc for rotation.
2. Establish attitude using attitude indicator after rotation.
3. Use airspeed or angle of attack thereafter.
(B) No.
(C) No. Theresultsareasdesired.
(D) [No comment. 3 (E) Yes. Rotate on airspeed the way we always have.
( I ? ) No.
(G) Prefer airspeed on takeoff. Did not try combination, but that might be best.
(H) No.
3. Was there any tendency to overrotate?
Pilot
-
(A) There was a tendency to underrotate because of the oscillatory nature of the angle-of-attack indication.
(B) No.
(C) Not initially, but i f the pilot initially underrotates, it leads to a tendency to overcorrect.
(B) [No comment. ] (E) No.
(I?) Yes.However, it could easilybecorrected.
(G) Not initially, since I had been briefed, but reached an abnormal (I felt) nose-high attitude on climbout.
(H) No.
4. After rotation, were airspeed and/or pitch oscillations induced?
Pilot (A) Some.
(B) Yes.
(C) Yes. This can happen at nearly constant angle of attack like a phugoid.
(D) [No comment. ] (E) No, since I fly primarily attitude and then just cross-check angle of attack or airspeed.
(I?) No.
(G) Airspeedwascovered.Seeprecedingcomment (B-3).
(H) No.
5. Could you trim adequately on angle of attack?
Pilot (A) Yes.
(Bj Yes.
(C) Yes,quitewell.
(D) Yes.
(E) Yes.
(F) Yes, at least as well a s when using airspeed.
(G) Yes, because I normally do not trim at cruise for airspeed. However, for slow flight, angle of attack and airspeed were about the same.
APPENDIX
APPENDIX (H) Yes.
6. In trying to fly on set values, were pitch oscillations induced?
Pilot (A) Yes. Had tendency to chase needle at first.
(B) Not in steady flight, but following any turn or change in speed.
(C) Yes.See comment, B-4. I wouldnotfly constantangle-of-attackcruise flight.
(D) More flight-path oscillations than pitch angle. This was the feeling, although pitch attitude and flight-path angle a r e the same i f angle of attack is constant.
(E) No, for same reasons as in question B-4.
( F ' ) None that were noticeable to the pilot.
(G) Not in stabilized flight - VFB.
(H) No.
7. During flare and touchdown, did aircraft response seem right for those maneuvers?
Pilot (A) Yes.
(B) Yes.
(C) Yes.
(D) Shortperiod,yes;flightpath, no.
(E) Yes.
(F) Yes.
(G) Yes, because the aircraft was flown visually from threshold.
(H) Yes.
8. Did the glide time between flare and touchdown seem right?
Pilot (A) Yes.
(B) Yes.
(C) It floats a bit i f any power is left on.
(D) Yes.
(E) Yes.
(F) Yes.
( G ) Yes, but thls factor was somewhat distorted due to shifting wind. At least one landing was downwind.
(H) Yes.
9. On short-field takeoffs and landings, did angle of attack seem to provide better control feel and response?
Pilot (A) No.
(B)Takeoff,no;landing,yes.Except at lightweight,[where]rollcontrolwas inadequate.
(C) No, but it quickly indicates a deviation from a desired condition.
(D) [No comment. ] (E) Landings, yes. Takeoff on angle of attack was absurd.
(F) Yes.
APPENDIX
APPENDIX (G) Not good for takeoff. Equal or better than airspeed on landings.
(H) Same.
C. Slow flightandmaneuverins Was angle of attack useful as a stall-warning reference?
1 .
Pilot
-
(A) Yes.
(Bj Yes.
(C) Not done.
(D) Yes.
(E) Very. Primary, It's great.
(F) Yes, very much so.
(G) Yes, but aircraft has good buffet warning.
(H) Yes.
Was there any noticeable lag time in the needle?
2.
Pilot (A) No.
(B) No.
(C) [No comment. ] (D) No.
(E) No.
(F) No. I would say that there was too much response if anything.
(G) No.
(H) No.
Did the needle seem to respond faster or slower than airspeed?
3.
Pilot (A) About same.
(B) Both systemsadequate.
(C) [No comment. 3 (D) Faster, too fast. Produced a tendency to chase it o r ignore it completely, (E) It responded to wheel motion; airspeed then lagged.
(F) Faster.
(G) About same.
(H) Did not notice.
Using angle of attack, was less throttle jockeying required to maintain altitude?
4.
Pi lot (A) About same.
(B) Not significantly o r consistently true.
(C) [No comment. 3 (D) Yes, plenty.
(E) No, mainly because I don't jockey the throttles. I set them and jockey the wheel.
(F) It appeared that less throttle jockeying was required.
(G) No.
(H) Did not notice.
I
APPENDIX
APPENDIX 5. You held altitude best using which system, airspeed or angle of attack?
Pi lot (A) About same.
(B) No difference.
(C) [No comment. 3 (D) Airspeed.
(E)Neither. I wassloppyeither way.
(F) There appeared to be no difference.
( G ) About same; probably held low speed more accurately with angle of attack.
(H) Did not notice.
D. ILS approaches 1. Your better performance was with which system, airspeed o r angle of attack?
Pilot (A) Did not do.
(B) No difference.
(C) Angle of attack.
(D)[No comment. 3 (E) Not applicable.
(F) Could not tell any difference.
(G) Not performed.
(H) [No comment. 3 2. Did angle of attack seem to alter your technique for any task?
Pilot (A) Did not do.
(B) Turn to final done at lower bank angle and lower airspeed with angle-of- attack system.
(c) Yes. Power manipulations were fewer and generally in one direction only
(i. e. , reduction).
(D) [No comment. 3 (E) [No comment. ] (F) I did not notice any change in technique.
(G) [No comment. 3 (H) [No comment. 3 E. General 1. Would you prefer angle of attack to airspeed for some maneuvers in this air- craft?
Pilot " (A) Would rather see both.
(B) No.
(C) Yes.Approaches,tightturns,steepclimbs,andsome I F R work.
(D) Airspeed for all.
(E) Yes, on landing approach - particularly the very slow approaches. Other phases of flight such as takeoff and cruise are not suited to angle of attack.
APPENDIX
APPENDIX ( F ' ) Yes. During approaches I think that this instrument would be very useful.
(G) For low-speed approaches it might be better, but it would take some getting used to. Possibly both would be best.
(€I) Yes.
2. Was there a noticeable decrease in pilot workload using angle of attack?
Pilot
-
(A) No.
iBj NO.
(C) Yes. I felt it was a substantial decrease (especially considering the panel layout).
(D) Moreworkload.
(E) On the approaches, yes; also much less nerve-racking on the approaches withangle of attack. Takeoffand cruise, no.
(F) Yes. I felt that it is somewhat easier to make approaches using angle of attack.
(G) Not significant.
(H) No.
3. Did angle of attack seem easier to fly?
Pilot
-
(A) No.
(B) No.
(C) Yes.
(D) No, harder.
(E) On the approach, yes; otherwise, no.
(F) Yes.
(G) Possibly at low speed.
(H) Seemed more secure on short-field approaches.
4. Didyou notice any significant advantages in using angle of attack?
Pilot (A) Very good indication of stall margin.
- (B) Good indication of stall margin.
(C) Yes. Reduces number of gages to scan.
(D) Trimreference.
(E) Yes, it made the approach less hairy.
(F) Automatically compensates for changes in gross weight.
(G) [No comment. J (H) Angle of attack will provide best reference in climbs or descents with changes of weight, etc.
5. Disadvantages?
Pilot (A) The oscillatory nature of the parameter.
(B) Tendency to concentrate excessively on angle of attack, This did not decrease much with familiarity.
(C) Yes. If one is fast to very fast, it is difficult to know exactly how fast (assuming no airspeed indicator).
APPENDIX
APPENDIX (D) If there were any advantages, these were marked by phugoid and power effects on trim and control and it all seemed more disadvantageous than advantageous.
I would like to try using angle of attack with an aircraft which had a pitch rate command system, free of aerodynamic trim changes and power effects.
(E) No.
(F) I evaluated the instrument as an additional cockpit instrument and not as a replacement. Under these circumstances, I found no disadvantages.
(G) [No comment. ] (H) Short-field approaches in strong, gusty winds could be a problem due to wind gradient and gusts.
6. Suggestions ormiscellaneouscomments?
Pilot
-
(A) First exposure to angle of attack resulted in I1chasingl1 the needle because it was the center of my attention; angle of attack, like airspeed, is best controlled by controlling attitude.
(B) [No comment. 3 (C) None, except that the task would be easier in a single-engine airplane.
Whether you want it easier is not known, perhaps it is desired to nearly saturate the pilot.
(D) [No comment. 3 (E) The angle of attack is a useful indicator for the approach and landing phase and, as such, could be a significant contribution to safety. During the other phases of flight, it is essentially useless, since airspeed or angle of attack are not primary. (For example, in cruise, power and rate of climb are primary. ) (F) On the ILS flight there was light-to-moderate turbulence encountered.
With this amount of turbulence, I could not tell any difference in the performance of flying the ILS approach. With any turbulence, I would prefer to fly airspeed. It appeared that 1 was better able to determine when turbulence was changing airspeed than I was able to determine changes in angle of attack due to turbulence.
(G) After some postflight thought and some discussion, I feel that the major advantage of the angle-of-attack meter would be for low-speed approaches at varying gross weights, particularly in an airplane in which the pilot was not highly experienced.
Since the evaluation was flown at essentially constant gross weight, this could not be evaluated. I did not like the angle-of-attack meter on the initial phase of the climbout and I would question its sole use for short-field or obstacle-clearance takeoff. With the airspeed for the initial phases it might be useful, but this was not evaluated. For either high-speed or low-speed cruise, including holding, I use power setting and altitude with the airspeed as a reference only, Therefore, it is doubtful if either the airspeed or angle of attack would be useful here. I didn't really evaluate it completely (I use power and airspeed for stabilized climb), so maybe the angle of attack would be an improvement, particularly for varying gross weights. However, since engine cooling is a consideration here, airspeed would also be required.
(H) [No comment. ] REFERENCES 1. Gilbert, James: What’syourangle? FLYING, April 1969, pp. 82-83.
2. Taylor, L. ; andHutchinson, J. : Angle of attack - A Proposal,ShellAviationNews, no. 359, 1968, pp. 2-9.
3. Gandelman, Julius H. : Evaluation of Angle of Attack Instrumentation in the Training of Student PilotstoPrivatePilotCertification. Rep. No. FAADS-68-19,FAA, Aug. 1968.
4. LaPlant, Porter 11; andJohnson,Alvinus P. : Evaluation of theGianniniDualStall Warning System and Stall Margin Indicators Installed in a C-133B. FTC-TR-67-5, U. S. Air Force, May1967.
6. Tuomela, C. H. : Angle of Attack as an Aid t o Flying.Tech.Rev. , VOl. 8. no. 1.
SOC.Exp. TestPilots,1966, pp. 44-55.
7, Fink,Marvin P. ; andFreeman,Delma C. , Jr. : Full-scale Wind-Tunnel Investi- gation of Static Longitudinal and Lateral Characteristics of a Light Twin-Engine Airplane. NASA T N D-4983, 1969.
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