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Loss of control recovery

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Loss of control recovery

Old 8th Sep 2016, 11:39
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Do a Hover - it avoids G
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Loss of control recovery

LOMCEVAC

I would welcome your comments adverse or otherwise on this:

There have been multiple threads about loss of control including the use of simulators.

May I suggest that any simulator can be used to practice the correct recovery drill following loss of control because the drill is not type dependant no matter how any aircraft or simulator behaves when control is lost.

The corect common recovery technique involves

1. Unloading the wing (stop pulling or trimming back thereby reducing the AOA to a low value well below the stalling angle) only then

2. Use rudder to get the ball roughly centre after which use aileron to level the wings

3. Ease, repeat ease, out of the resulting dive or climb

While going through these steps it is common sense to close the throttle if the nose is low and add power if the nose is high.

Clearly the presence of the ground could require the pullout to be firmer but no more than to the edge of the buffet.

JF
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Old 8th Sep 2016, 16:48
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and add power if the nose is high.

Careful; on some types????? Better to get the nose down first then add oomph.
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Old 9th Sep 2016, 00:25
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Pupils at Hamble would practice something rather similar on the Link Trainer D2, preferably using the "Rough Air" setting to obtain what we expected might be even more realistic - but this was in 1949, and we were all just starting a CPL course.

( The Link's only "engine" was fuselage mounted, I think. So no "Underslung Engine" effects for us !)
LT
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Old 9th Sep 2016, 15:34
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1. Unloading the wing (stop pulling or trimming back thereby reducing the AOA to a low value well below the stalling angle) only then

2. Use rudder to get the ball roughly centre after which use aileron to level the wings
Agree with Note 1 but a bit concerned about Note 2 (using rudder to centre the skid ball during a UA recovery) The Boeing 737 FCTM recommends unloading while simultaneously using up to full aileron to level the wings.
After all, the act of unloading gives immediate better aileron control. Using rudder to centre the skid ball in a jet transport gives a strong yawing moment which is not desirable since is leads to a roll.

According to the 737 FCTM the only time you would consider applying rudder is if a very nose high, rapidly decreasing speed situation has occurred. The FCTM states:
"A nose high, high angle of bank upset requires deliberate flight control inputs. A large bank angle is helpful in reducing excessively high pitch attitudes. The pilot must apply nose-down elevator and adjust the bank angle to achieve the desired rate of pitch reduction while considering energy management.

Once the pitch attitude has been reduced to the desired level, it is necessary only to reduce the bank angle, ensure that sufficient airspeed has been achieved, and return to level flight.
If full roll control application is not satisfactory, it may be even necessary to apply some rudder in the direction of the desired roll. Only a small amount of rudder is needed. Too much rudder applied too quickly or held too long may result in loss of lateral and directional control or structural failure.'

I wouldn't be too keen on risking structural failure if the rudder was mis-used during the attempted recovery. Using the rudder to place the skid ball roughly central, before using aileron, might be chancing your arm.

Then again it may all depend on the aircraft type.
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Old 9th Sep 2016, 15:53
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Centaurus,

I would also caution about the use of rudder. On VC10, 707 and 747 C of A test flights we were told not to use rudder because of the strong yaw/roll coupling.
The drill was as JF has said, (1) and (3) but to correct any wing drop with aileron.
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Old 10th Sep 2016, 06:56
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On reflection, I think JF is right because, during C of A stall tests, one always took great care to eliminate any sideslip while reducing speed before the stall. The main thing was to use aileron and not rudder to correct a wing drop.
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Old 11th Sep 2016, 00:10
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Who is Lomcevak?
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Old 11th Sep 2016, 00:51
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Originally Posted by John Farley View Post

The corect common recovery technique involves

1. Unloading the wing (stop pulling or trimming back thereby reducing the AOA to a low value well below the stalling angle) only then

2. Use rudder to get the ball roughly centre after which use aileron to level the wings

3. Ease, repeat ease, out of the resulting dive or climb

While going through these steps it is common sense to close the throttle if the nose is low and add power if the nose is high.

Clearly the presence of the ground could require the pullout to be firmer but no more than to the edge of the buffet.

JF
While rudder use is not prohibited in this situation in the 777, it has capital bold letters following an asterisk stating "WARNING: EXCESSIVE USE OF PITCH TRIM OR RUDDER MAY AGGRAVATE AN UPSET SITUATION OR MAY RESULT IN LOSS OF CONTROL AND/OR HIGH STRUCTURAL LOADS". This is not the only type that Boeing has this statement for.

The 777 also says for a nose-high recovery to "reduce thrust".
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Old 11th Sep 2016, 11:24
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While going through these steps it is common sense to close the throttle if the nose is low and add power if the nose is high.
Not in a 747-400. Boeing says: (nose high, low speed)

Further complicating this situation, as the airspeed decreases, the pilot could intuitively make a large thrust increase. This causes an additional pitch up.
There is no single drill for the 747 upset recovery, I would also take issue with
the drill is not type dependant no matter how any aircraft or simulator behaves when control is lost.
I used to teach "Height - Speed - 'g' - Roll - Pitch - Trim" in a Jet Provost, but this doesn't work for (e.g.) a 747 with a huge thrust couple...

Boeing again:

Though flight crews in line operation rarely, if ever, encounter an upset situation, understanding how to apply aerodynamic fundamentals in such a situation helps them control the airplane. Several techniques are available for recovering from an upset. In most situations, if a technique is effective, it is not recommended that pilots use additional techniques.
and

Finally, if normal pitch control then roll control is ineffective, careful rudder input in the direction of the desired roll may be required to induce a rolling maneuver for recovery. Only a small amount of rudder is needed. Too much rudder applied too quickly or held too long may result in loss of lateral and directional control. Because of the low energy condition, pilots should exercise caution when applying rudder.
JF, if you wish, I will email you the text of the 747-400 upset recovery chapter from the Flight Crew Training Manual...
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Old 11th Sep 2016, 12:41
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When I used to fly a Pitts regularly, my instinctive reaction to the rare occasions when the world started spinning in unintended ways was to close the throttle and reverse whatever control inputs I had in. This stopped the world spinning every time and so I never had cause to work on refining the recovery or finding a back up.

In reference to airliners I think that a pilot who is on the ball enough to be able to competently and efficiently recover from a UA probably wouldn't have got into the situation in the first place. Assuming that a pilot has allowed a UA to develop we must also assume that their skills are most likely average at best.
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Old 11th Sep 2016, 17:18
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Not strictly accurate. It is worth reading this report from a Ryanair 737 at Eindhoven to see how a momentary loss of SA chasing an approach leads to the automatics putting the aircraft in an upset close to the ground.

In this case, it was the FO who recovered the aircraft from a very nasty situation with no warning.

Link fixed

Last edited by Jwscud; 12th Sep 2016 at 12:16. Reason: Fix broken url
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Old 11th Sep 2016, 18:22
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The problem of identifying a common drill reflects the widening gap between certification requirements and operational need.
Every aircraft can have a 'normal recovery technique' (FAR / CS 25.202, c, 3), where 'normal' may be type or manufacturer specific.
Operators seek similarity and consistency across aircraft types to reduce cost and avoid 'negative transfer' in training (N.B. protected vs unprotected aircraft).

Then there are segments of the industry which chase the last accident, attempting to develop techniques and training for unique circumstance - e.g. issues of trim and thrust.
A compounding problem is that accident reporting, or readers' interpretations, often focus on the outcome - loss of control. The preceding events, operational situations, and other contributing factors can be overlooked, and thence the opportunity to consider avoidance or mitigating actions.
Fortunately the widespread enthusiasm for 'after the event' upset training is now being refocused on avoidance, possibly due to the realisation that it is impossible to train 'every' situation, or appropriately represent all scenarios, and above all overcome the limitation of simulation - that there is no real fear (surprise) in a simulator.

Whilst I would not disagree with the general proposals being discussed, it is important to consider context. Those aspects which are required to be demonstrated in certification may not cover all scenarios which pilots appear to be able to encounter in operation; the industry needs to acknowledge the gap between what is assumed to happen, certification, and what actually happens in operation. This also involves recovery techniques.

An alternative to requiring compliance at 'accident' extremes, or providing training for the fallible human, is to consider the benefits of avoiding the situations, which are closely related to the gross assumption in most procedures - that the pilot understands the situation.

First is the aircraft stalled, what are the cues.
What is the trim position relative to the flight condition, how is this determined.
Centre the ball - lateral acceleration indication; rarely used, engine failure or not at all with automatic compensation.
Roll to the nearest horizon; crews may not normally use the blue / brown horizon thus it's difficult to determine the nearest horizon with a high nose up attitude. Alternatively, use the roll (sky) pointer, but again rarely used as attention is often centralised on the aircraft symbol; worse still the dominance of FD use may create the expectation of a FD recovery.
If this is a likely scenario, then training for stall recovery may also have to teach pilots a new way of flying in that situation; often misinterpreted as the loss of basic skills!
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Old 12th Sep 2016, 14:34
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At the risk of being ridiculed, I think it is all a storm in a tea cup. I was fortunate enough to be military trained (didn't cost me a cent) where aerobatics and all sorts of unusual attitudes on instruments were taught in wartime designed aircraft such as the Wirraway (Harvard look-alike but more unforgiving).

The basics of stall recovery and unusual attitude recovery haven't changed that much since those days. From reading some the publically available accident reports, nearly all involved either night or IMC accidents where absence of basic instrument flying skills was the direct cause of the crash.

All the level D flight simulators I have flown have glass cockpit displays where 360 degrees of roll and very high and low pitch attitudes are available on the artificial horizon or PFD. Any competent simulator instructor should be able to demonstrate an unusual attitude recovery from fully inverted, to the various combinations of high and low angle attitudes, spiral dives, extreme nose up high angle of bank and so on. The technique for recovering from these various attitudes is well covered in the applicable FCTM and a host of other publications.

While the G forces involved may not be experienced in a full flight simulator, that doesn't matter. The aim in this sort of training is to correctly interpret what the flight instruments are telling you. This can be done by using the simulator visuals on CAVOK followed by the same manoeuvres in simulated night and/or IMC.

If students with 100 hours could successfully recover from all sorts of unusual attitudes in a Wirraway while under the hood, on limited panel, and with gyro instruments caged, with an instructor teaching him, then how simple is it to be taught the same manoeuvres in a Boeing 737 flight simulator with much more reliable flight instruments?

Providing the simulator instructor is competent to demonstrate rather than sit in the instructor panel seat and try to talk a student through a manoeuvre, then the basics of stall recovery and unusual attitude recovery on instruments can be covered inside 30 minutes of simulator time.
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Old 12th Sep 2016, 18:05
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In reference to airliners I think that a pilot who is on the ball enough to be able to competently and efficiently recover from a UA probably wouldn't have got into the situation in the first place. Assuming that a pilot has allowed a UA to develop we must also assume that their skills are most likely average at best.
I think that has a ring of truth about it. If itís the aeroplane thatís caused it despite your best efforts then itís in the lap of the gods anyway.

It always seemed to me that the kind of ďclose your eyes... Tadaaa!Ē sim instruction would be much better directed towards practice at recognising the symptoms of impending doom and doing something about it before itís too late.

Agree with much of what Centaurus has said, too.
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Old 13th Sep 2016, 20:51
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I don't know; We did unusual attitude recovery in Warriors, (single engine piston), for our ATPL, which was very useful, and judging by the amount of recent incidents and accidents where pilots have manifestly failed to scan their instruments and actually FLY their aircraft; I think it would be very beneficial to do UARs in Airliner SIMs too.

With so much automation in our aircraft, a lot of SIM time needs to be spent practising ECAM/EICAS drills etc, and basic piloting is increasingly taken as read and not practised. But basic handling :- speed + attitude = performance, and a good instrument scan is still absolutely fundamental to our craft.
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