Flight Directors off for stall practice in the simulator.
 

It is well known there are operators who mandate that the flight directors must be on and programmed for all phases of flight. There may well be technical reasons for this depending on aircraft design. That said, it would be no surprise to some, that automation dependency also plays a significant part with those sort of company directives.

During type rating training in simulators the approach to stall and stall recovery is usually practiced. This includes during on final approach in the landing configuration where ground contact is a factor. The pre-flight briefing may include FCTM advice such as "Ensure the proper flight director modes are selected for the desired manoeuvre. If the FD commands are not to be followed the FD should be turned off. Do not use the FD commands during stall recovery. FD commands are not designed to provide guidance to a recovery or approach to stall or stall."
The QRH also states under Approach to Stall or Stall recovery, a Note which says "Do not use flight director commands during recovery."

Having now set the scene, the decision has to be made by the instructor whether or not to turn off the FD for the exercise. On the other hand, as it is likely that in real life the FD will already be on during the instrument approach during which a stall or approach to stall has occurred, maybe the FD should be turned off for the recovery? After all, Boeing advice is: "If the FD commands are not to be followed the FD should be turned off."

Some may argue that because a go-around will take place once the aircraft has recovered from the stall, the FD should remain on during the manoeuvre to provide pitch guidance for levelling out at the missed approach altitude, if the stall occurred in IMC. Their argument being that the pilot should avoid being distracted by un-programmed FD indications and that he should be able "look through" the FD needles to see the nose attitudes during stall recovery. While some pilots claim that they can "look through" the FD indications to see what is behind them, others claim they are seriously distracted trying to see behind the needles and prefer to turn off the FD as part of the recovery.

The catalyst for this post was a colleague who was given a "Fail" mark for requesting his PM to immediately switch off both FD's as part of the recovery from the approach to stall. The instructor was of the view the FD should be left on during the whole exercise since the pitch bar indication would serve as a reminder of the missed approach altitude. While that may be true, nevertheless the priority in such a situation is a proper appreciation of nose attitude during the recovery; particularly as GA thrust used where ground contact is a factor, would cause a strong pitch up change of trim and may even lead to a delayed stall recovery. This is where raw data instrument flying skills become paramount. As Boeing reiterates: "Do not use FD commands during recovery." This would suggest that in event of an inadvertent stall the FD should be switched off so that pilots are not seduced into following erroneous or inappropriate FD commands .
Comments appreciated.

In defence, m'lud:

The exercise was stall recovery. Did I achieve that satisfactorily? Yes. Is there a company SOP about FD's ON/OFF? No. Therefore should that have any effect on the assessment of the manoeuvre? No. IMHO. (TRE). Sounds like personal opinion, and failing on that basis for a specified manoeuvre seems overly harsh.
Should PF, during the startle factor of a stall recovery, be giving priority to FD's ON/OFF? Debatable. Should a current pilot be able to control attitude without an FD? Yes. FD is OFF, stall is recovered, TOGA is pushed with MAA set, would not the FD reappear until ALT AQ? Should that cue be enough for the level off? Probably.
Surely a fail for such an item has an appeal to HOT?

Couldn’t agree more. Time-critical event training is all about reinforcement of technique for dealing effectively with something that would likely lead to a crash in short order if uncorrected. Stall, hard GPWS, windshear, airspeed unreliable, etc. The last thing you should be thinking of while flying these manoeuvres is artificial altitude constraints. It’s an emergency: the sky is yours.

Yes, when back in a normal flight regime you can start paying more attention to clearances, altitudes and the like but that’s sugar frosting compared with handling the escape correctly.

That being so, why not leave the FD on while conducting steep turns as part of an IPC? After all, the pitch bar may help you to maintain altitude and the roll bar reminds you when to straighten up on the original start heading.. .

FDs should be switched off if they are not to be followed is a general suggestions. It is applicable for any planned situation like visual approach. Steep turns are not done in commercial aircraft. Stall is not a planned manoeuvre. Once the aircraft has stalled at lower altitude immediate memory items for recovery should be applied i.e. lowering the nose, application of required thrust etc. Pilot who is doing the recovery should have the knowledge that FDs don't provide unstall guidance and ignore and just fly the attitude. If it's not in the procedure why waste time switching off FDs? It's a serious event and should have a standard procedure.

In the US on the ATPL practical test and initial type training a 45 degree bank angle steep turn must be completed

We could always go a bit radical and fly the recovery as specified by the manufacturer.

So that we don't remove the 5 minutes per year of practice of raw data flying that airline pilots get?

Actually, you can use the FD; one useful information is the altitude selected (if it was). It is easy to climb back to cleared altitude while using the FD after recovering.

Sure! But isn't this a simulator exercise? We practice in simulator many things that are not that easy to acquire competance to do them in real life when the need arises. In Airbus if stall happens when the bird is on hitting TOGA will bring FDs back. So good practice to fly ignoring FD. I think the important thing is to be able to apply immediate recovery actions with or without FD.

FD may confuse
 

just like in TCAS RA, stall recovery has nothing to do with FDs. FDs must be switched off if you get into stall for more focused recovery.

INDIGO
Surely FDs have nothing to do with recovery from stall and they can be confusing if one doesn't know that they are not to be followed. In TCAS immediate action is FDs off and it is mandatory for a different reason. In automatic TCAS you don't switchoff the FD. EGPWS is a memory item where you ignore FDs. Stall recovery also is a memory item and it doesn't contain action on FDs. In low level stall one doesn't know how much height will be lost. The immediate actions in a stall are reduction of a AoA, wing level, thrust as required, checking speed brakes in which the PF must do before doing anything else. Forgetting any of these can be fatal. Putting the nose below the horizon with FD on or off should not be a such big deal. You may be doing the approach with the bird and if switch off FD first it will reappear with TOGA then you again switch it off? Obsession with FD off which is not essential action can also become a distraction and make you forget something more critical to recovery.

Easier said than done; like ignoring the guy coming your way at night and blinding you with his headlights on High beam

Airline pilots probably spend 95% of their flying hours following flight director commands. All the more reason for switching the FD off in a critical situation like a stall recovery where blindly reverting to habit and following FD needles could lead to a more serious problem.

Then why it is not a memory item? All memory items are laid down procedures. Is it because the manufacturer is not capable of thinking like us? And about stall only the test pilot has actual experience. It may not be easy that is why we practice in the Sim. Switching off FD is helpful but not at the cost of mandatory actions. Flying accurately and not stalling in the first place appears simpler than recovery. Most stall incidents are because of poor flying.

My thoughts exactly:ok: Fairly pointless discussion about the FDs.

FDs are great tools for guidance but pilots should know when it's time to ignore them even in normal daily operations: For example a very bumpy approach couple with a potentially unstable glideslope guidance ( Eg Beijing ILS 36L) trying to chase the FD bars accurately when the aircraft is tossing around is almost impossible and certainly not recommended. Knowing the pitch and power of your aircraft is a must.

Interesting observation. Hand flying while following FD commands normally requires full concentration on keeping the FD needles centred in the tiny square. The theory being if the needles are exactly centred then eye scanning of other pertinent instruments are of secondary importance. Pundits will claim that despite FD's being prominently displayed, the pilot should still use the six pack scan in the PFD. Ideally yes - but that rarely occurs. With many pilots, Situational Awareness can go out the window the moment they are locked on to the FD.

With engine failure at V1 and continue, some pilots have trouble following FD commands and often overcorrect. The result is they start to chase the needles which only makes things worse. One temporary solution is to switch off the FD. This clears the PFD so the pilot can concentrate on the "little aeroplane" nose attitude and bank indications. Others simply switch their scan to the standby ADI and fly on that, which is devoid of distracting needles. When introducing engine failures on take off for the first time, it can be helpful for the candidate to practice these with FD's off so that a clearer picture of the artificial horizon is seen without the distraction of wavering FD needles . Once the candidate is competent at flying this raw data display, FD use can be introduced.

Manufacturer keep revising abnormal procedures in the light of new information. Even memory items have been revised time and again. Having conflicting information display is not good airmanship. If not PF, it may confuse the PM and trigger wrong callouts. We also have danger of mode reversion if we don't follow the FDs.

Indigo
you yourself just started and ended this thread. So what happened to your opinion now? Stall recovery is a memory item more serious than that. Nobody follows FDs in stall recovery but when exactly you switch them off? What is the priority. Why not check with the manufacturer first and let us know?

INDIGO
That is interesting. Since we are discussing stall we can only be in alternate law. So no hard protections which cannot be overridden and no auto pilot. ATHR may or not be there.Now let's see mode reversions. I assume you are referring to Speed protection when FD orders are not followed by the flight crew(AP NOT ENGAGED). In these protection there are two dimensions one is when the speed increases to VMAX+4 and the other is when speed decreases to VLS-2 or with speed brakes extended VLS-2 to VLS-19. Speed increase won't bother us because aircraft will not stall. If speed decreases below the value mentioned above then So again no stall so where the danger that you see. Rather it is good. The very purpose of reversion is to prevent speed reduction below unsafe level.

If you treat stall as an upset then in FCTM Upset Prevention and Recovery Nose High recovery it suggests disconnection of AP and ATHR.

From a practical point of view, B737, the stall recovery manoeuvre would likely be prompted by the stick shaker. The response should be instinctive. The incipient stall would be broken PDQ. My concentration would be on that; i.e. attitude, speed then power. It would be pretty quick, even at altitude. I doubt I'd have the time to think about FD's or not.

Stall recovery is a flying technique, not an ECAM drill or QRH/FCOM procedure.

Airbus golden rule says use appropriate level of automation and I consider FD as part of automation. In stall recovery, main action is lowering the nose. Afterward, it is about recovering the speed and flight path. At this time, if FDs give me conflicting information, I would ask for turning them off.

This can be a subject of a new thread. Stall is very much part of FCOM and QRH Abnormal Procedures. It is also a drill. Only difference is it is done by memory because life is too short. It is part of abnormal procedures in both the documents mentioned.

This is from Flight Crew Techniqes Manual

Good luck turning them of on the CSeries. They come on automatically at under-speed and you cant turn them off until you are recovered.

And still the pilots fly without raising a hue and cry? Shall I call them brave?

So the only reason for that behaviour would be that the flight director actually gives useful cues to get back to speed. Sounds like a good feature for Airbus, kinda like a mental stick pusher for followers of the magenta line.

Personal take...

F/D's on/off during a stall recovery... In my book, whatever. As quoted above, you ignore them anyhow.

My issue is distracting the PM (essential part - right!) from the monitoring task during the recovery by asking for the FD's off. The PM simply isn't expecting it! Will take them by surprise and distract them from the key monitoring function.

Was it a fail though? Errrm, (IMHO) No way! Discussion item, but only if the examiner is feeling picky!

Then he is going to get one hell of a surprise when something really serious happens on his watch if hasn't the cognitive capacity to switch off a FD switch in the one second it takes to do so. Jesus Wept. Has aviation got to the stage that we have to baby pilots that much, or are we so overwhelmed by the myriad of SOP's that are pushed down our throats in today's airline flying, that one slight item out of order is practically a Mayday situation?

Ok...Take this from the PF point of view...

Do you want them distracting themselves by looking at the FD, thinking of random rule number 17 and three quarters, thinking 'well I'm not following that so I must call for it to be turned off' (your myriad of SOP's...) or do you just want them to unload the wings using a simple tried and tested method and recover the aircraft.

ie. concentrating on the core task of recovering the aircraft in a time critical scenario.