Flydubai crash at RVI final report out
From the accident report, when the HUD reverts to upset mode, the mental reference has to change from FPA to attitude; - this requires significant mental readjustment. Also the FD is removed.
This was noted by Fursty Ferret in Flydubai crash at RVI final report out , and that the “The HUD symbology on both the 737 and 787 is pretty terrible”, but how is this reported to the regulators, considers equipment reassessment or associated SOPs, checks training implications, etc, …
The change of ‘mental model’ - switching from one format to another could be similar to reverting from head down instruments to visual, which has been shown to take 2-4 secs, i.e. a delay in re-establishing sufficient awareness for the task - upset recovery.
Other questions about the HUD; the accident report shows views of the HUD during the approach, it is unclear if these are either a mathematical simulation or from a training simulator.
Assuming that the top-right dial display is AoA, then the adjacent digital values appear not to correspond with the aircraft manoeuvre and speed.
Nose up, fig 65, 1.4. Alternatively in fig 66, -0.6.
Nose down, fig 70, 3.6.
Why should this be ?
And for all those who demand “we must have AoA displayed - upset recovery”; the HUD Upset / de clutter mode removes the AoA display !!!
Anyone able to confirm this via training simulator / real aircraft / HUD.
This was noted by Fursty Ferret in Flydubai crash at RVI final report out , and that the “The HUD symbology on both the 737 and 787 is pretty terrible”, but how is this reported to the regulators, considers equipment reassessment or associated SOPs, checks training implications, etc, …
The change of ‘mental model’ - switching from one format to another could be similar to reverting from head down instruments to visual, which has been shown to take 2-4 secs, i.e. a delay in re-establishing sufficient awareness for the task - upset recovery.
Other questions about the HUD; the accident report shows views of the HUD during the approach, it is unclear if these are either a mathematical simulation or from a training simulator.
Assuming that the top-right dial display is AoA, then the adjacent digital values appear not to correspond with the aircraft manoeuvre and speed.
Nose up, fig 65, 1.4. Alternatively in fig 66, -0.6.
Nose down, fig 70, 3.6.
Why should this be ?
And for all those who demand “we must have AoA displayed - upset recovery”; the HUD Upset / de clutter mode removes the AoA display !!!
Anyone able to confirm this via training simulator / real aircraft / HUD.
Join Date: Jul 2002
Location: Netherlands
Age: 71
Posts: 165
Likes: 0
Received 0 Likes
on
0 Posts
Why is it that in the airline industry the HUD seems to be a cheepo version of what the mil guys use? AFAIK their flying relies a lot on HUD, no matter what attitude they are in.
Again, I can't relate to own experience, never flew in mil A/C nor used a civvy HUD.
At least this thread learned me why airlines choose for a HUD to make CAT 1+ landings, iso a dual A/P... They are way cheaper!
Again, I can't relate to own experience, never flew in mil A/C nor used a civvy HUD.
At least this thread learned me why airlines choose for a HUD to make CAT 1+ landings, iso a dual A/P... They are way cheaper!
Double Back.
Civil HUDs are not cheap; flight operations are significantly different from military use.
HUD certification can be just as expensive as a fully capable AP, and then involve additional training costs, and currency requirements.
A previous comment that the accident operator traded AP servicing cost for HUD use, appears to show how easy it is to misjudge relative cost and safety.
Other issues relating to HUD operations are discussed in
Use of HUD for visual approach and landings
Civil HUDs are not cheap; flight operations are significantly different from military use.
HUD certification can be just as expensive as a fully capable AP, and then involve additional training costs, and currency requirements.
A previous comment that the accident operator traded AP servicing cost for HUD use, appears to show how easy it is to misjudge relative cost and safety.
Other issues relating to HUD operations are discussed in
Use of HUD for visual approach and landings
Illusions .
Section 2.4 of the report discusses the possible effect of somatogravic illusions (page 166) - longitudinal acceleration and false pitch perception.
Discussion in the 737 Max thread raises associated issues of sensed pitch rotation with reduced vertical acceleration (g). The report does consider ‘negative g’ perhaps using a wider definition of illusion as a false sensation, and separately considers issues of pitch control and trim which contribute to the pilots sensation of flight path and aircraft feel - control feedback.
Normal flight conditions range 0.8 to 1.3 g, generally in a steady sate between manoeuvres; greater g values can be encountered for short duration, e.g. turbulence. Aircraft motion (sensed acceleration) relates to control movement and stick force, and ‘seat of the pants’ feedback referenced to general experience.
Abnormal, infrequently encountered conditions, may require larger stick inputs which could contribute to the assessment that additional trim is required. Alternatively the aircraft trim changes quickly due to speed increase, large change in thrust (pitching moment), or configuration change, thus requiring more pilot control input and longer duration trim change.
In pushover manoeuvres the pilot could experience reduced g more than generally experiences (often reported as negative g); in this condition pilots can encounter combined reduction in g, and negative pitch rate simultaneously. Also with the need for nose down trim and large stick defection the flying task is beyond normal expectation which could be interpreted a false sensation - like an illusion - even surprise. Large stick inputs in GA configuration at low speed, differ significantly from normal flight experiences - only requiring small stick input at higher speeds.
Thus during a GA the pilot may be reluctant to use large stick defections to avoid unusual g conditions; or with larger control input quickly seek to reduce the higher stick force with longer periods of trim.
In either case the pilot is experiencing less g than normally experienced, simultaneously with the unusual pitch change and control feel in a very short time scale. The combination could contribute to poor understanding of the aircraft flight condition, which with false sensation reduces the ability to correctly interpret the situation and apply corrective control inputs and trim - particularly where the duration of abnormal control change and sensations are longer than normal experience suggests.
Any thoughts on this view ?
Discussion in the 737 Max thread raises associated issues of sensed pitch rotation with reduced vertical acceleration (g). The report does consider ‘negative g’ perhaps using a wider definition of illusion as a false sensation, and separately considers issues of pitch control and trim which contribute to the pilots sensation of flight path and aircraft feel - control feedback.
Normal flight conditions range 0.8 to 1.3 g, generally in a steady sate between manoeuvres; greater g values can be encountered for short duration, e.g. turbulence. Aircraft motion (sensed acceleration) relates to control movement and stick force, and ‘seat of the pants’ feedback referenced to general experience.
Abnormal, infrequently encountered conditions, may require larger stick inputs which could contribute to the assessment that additional trim is required. Alternatively the aircraft trim changes quickly due to speed increase, large change in thrust (pitching moment), or configuration change, thus requiring more pilot control input and longer duration trim change.
In pushover manoeuvres the pilot could experience reduced g more than generally experiences (often reported as negative g); in this condition pilots can encounter combined reduction in g, and negative pitch rate simultaneously. Also with the need for nose down trim and large stick defection the flying task is beyond normal expectation which could be interpreted a false sensation - like an illusion - even surprise. Large stick inputs in GA configuration at low speed, differ significantly from normal flight experiences - only requiring small stick input at higher speeds.
Thus during a GA the pilot may be reluctant to use large stick defections to avoid unusual g conditions; or with larger control input quickly seek to reduce the higher stick force with longer periods of trim.
In either case the pilot is experiencing less g than normally experienced, simultaneously with the unusual pitch change and control feel in a very short time scale. The combination could contribute to poor understanding of the aircraft flight condition, which with false sensation reduces the ability to correctly interpret the situation and apply corrective control inputs and trim - particularly where the duration of abnormal control change and sensations are longer than normal experience suggests.
Any thoughts on this view ?
Join Date: Aug 2006
Location: Looking for the signals square at LHR
Posts: 236
Likes: 0
Received 0 Likes
on
0 Posts
In either case the pilot is experiencing less g than normally experienced, simultaneously with the unusual pitch change and control feel in a very short time scale. The combination could contribute to poor understanding of the aircraft flight condition, which with false sensation reduces the ability to correctly interpret the situation and apply corrective control inputs and trim - particularly where the duration of abnormal control change and sensations are longer than normal experience suggests.
Any thoughts on this view ?
Any thoughts on this view ?
Just an observation rather than a useful thought.
Join Date: Jun 2007
Location: Wanderlust
Posts: 3,403
Likes: 0
Received 0 Likes
on
0 Posts
a5701
When learning instrument flying it is repeatedly drilled into you to ignore bodily sensations and feelings and only react to what instruments tell you about the situation. Some where this message seems to be lost. Whether it is AF447, QZ8501, or Rostov OD in all of these large scale pitch inputs are given without any reference to attitude display on PFD or HUD. In the present RoD case despite the PM's excellent support the PF continued to push and trim without checking the result on the attitude. Even the increasing speed should have triggered pitch up and not a pitch down reaction. It appears to be case where the pilot was overwhelmed and mentally incapacitated and the resulting control inputs were without any thought or rationale. The PM was monitoring and verbalizing everything wish he had taken over.
When learning instrument flying it is repeatedly drilled into you to ignore bodily sensations and feelings and only react to what instruments tell you about the situation. Some where this message seems to be lost. Whether it is AF447, QZ8501, or Rostov OD in all of these large scale pitch inputs are given without any reference to attitude display on PFD or HUD. In the present RoD case despite the PM's excellent support the PF continued to push and trim without checking the result on the attitude. Even the increasing speed should have triggered pitch up and not a pitch down reaction. It appears to be case where the pilot was overwhelmed and mentally incapacitated and the resulting control inputs were without any thought or rationale. The PM was monitoring and verbalizing everything wish he had taken over.
Last edited by vilas; 16th Dec 2019 at 06:07.
Gipsy Queen, thanks for your observation; it is a very useful thought - to avoid the assumption that pilots will experience the same accelerations as recorded by the FDR.
vilas, as much as we train pilots to ‘mask’ illusionary effects by focussing on the instruments, we cannot guarantee success in every situation; not for every pilot, not now nor future.
Thinking about your point “where the pilot was overwhelmed and mentally incapacitated”, this could be related to an effect of surprise. Yet the regulators are now considering methods of training pilots to be ‘resistant’ to surprise, with the belief that basic human reactions can be sufficiently suppressed, again, with what confidence.
The industry really has to accept that there are limits to what can be trained, or what pilots can recall / replicate in today’s complex situations. We must re-examine the situations and equipment in them which have to be managed.
Also, similar issues apply to monitoring and intervention (CRM). Instead of citing human error, failure, more training, it is time to accept that pilots are doing their best in the situation as they understand it. Either the situations are more complex, humans less experienced in understanding, or more likely both.
The modern safety phrase - work as imagined - not being the same as work as done, - as identified in accidents. We need to change the way we think about these issues.
A thought ‘out of the box’: pilots suffer illusions, but are they only consequential during manual flight. With autos engaged there are no adverse effects on motor skills irrespective of wether the pilots believe the instruments or not.
vilas, as much as we train pilots to ‘mask’ illusionary effects by focussing on the instruments, we cannot guarantee success in every situation; not for every pilot, not now nor future.
Thinking about your point “where the pilot was overwhelmed and mentally incapacitated”, this could be related to an effect of surprise. Yet the regulators are now considering methods of training pilots to be ‘resistant’ to surprise, with the belief that basic human reactions can be sufficiently suppressed, again, with what confidence.
The industry really has to accept that there are limits to what can be trained, or what pilots can recall / replicate in today’s complex situations. We must re-examine the situations and equipment in them which have to be managed.
Also, similar issues apply to monitoring and intervention (CRM). Instead of citing human error, failure, more training, it is time to accept that pilots are doing their best in the situation as they understand it. Either the situations are more complex, humans less experienced in understanding, or more likely both.
The modern safety phrase - work as imagined - not being the same as work as done, - as identified in accidents. We need to change the way we think about these issues.
A thought ‘out of the box’: pilots suffer illusions, but are they only consequential during manual flight. With autos engaged there are no adverse effects on motor skills irrespective of wether the pilots believe the instruments or not.
Join Date: Jun 2007
Location: Wanderlust
Posts: 3,403
Likes: 0
Received 0 Likes
on
0 Posts
as much as we train pilots to ‘mask’ illusionary effects by focussing on the instruments, we cannot guarantee success in every situation; not for every pilot, not now nor future.
Thinking about your point “where the pilot was overwhelmed and mentally incapacitated”, this could be related to an effect of surprise. In taking a decision and executing a go around which is a well practiced manoeuvre where is the surprise?
The point is although the g forces, sensations are same for both pilots the PM was not affected by them and was guiding the PF correctly. Despite clear cut guidance by PM to maintain the pitch PF wasn't able to do it. Should there be some guideline as to how much deviation the other crew member should accept before physical intervention otherwise we learn nothing from these loss of lives.
The somatogravic illusion isn’t something new, it hasn’t just been invented, the sims actually don’t do a bad job at replicating the same- those of us used to flying some geriatric but over powered military types in a previous existence did exotic manoeuvres at night and/or in IFR and will have experienced the over whelming sensation of feeling they are pitched up at some horrible angle whilst in actuality being S&L and telling themselves. “For f**** sake whatever you do don’t push”...as you correctly said earlier Vila’s it was drummed into us that you flew the instruments, not the seat of your pants..,....so what happened here?
so why didn’t the P1 do so that night on the second go - around..?fatigue.? And is there a case for the guy who is heads heads down in such circumstances (in this case the P2) doing the actual GA (not a HUD user myself).
Where is the surprise …
Surprise, J Reason; “ a profound discrepancy between one's perception of the world and the reality” (which could include illusions)
Having decided to fly a GA - the second occasion, perhaps not a significant surprise even though it conflicted with what was planned - expected - hoped for.
A larger surprise effect could emerge from the difference between the lighter weight GA and perhaps slower pitch response in following the FD. A difference in ‘the conditioned expectation of normalcy’.
Also increased or ‘new’ surprise from the unexpected, even unknown automatic change of HUD format to ‘upset’, with additional problems in changing mental focus and assessing the flight path within HUD - previous discussions.
The effect of surprise together with the stick feel/position trim characteristics could have contributed to the excessive nose down pitch response and continued trim operation (‘2.2. On the peculiarities of the trim (relief) of forces’: page 159).
If the 737 is normally flown with the combination of small stick movement, quickly followed up with trim ‘blips’ (note Boeing cautions not to use fly the aircraft with trim). Then depending on personal technique it is possible that with the stress of the situation that the trim blips merge into one, which together with slower pitch response than anticipated - slow speed, high nose up attitude, and max GA thrust, the aircraft is inadvertently flown with trim. If the stick is not centred to judge the effectiveness of trim - reduced stick force, then the aircraft continues to pitch nose down with trim still applied to counter the erroneous stick force from pushing the stick forward.
Recent ref for surprise - https://pure.tudelft.nl/portal/files...on_startle.pdf
Good background on the mechanism and effects of surprise, that it can occur without startle, and build up relatively slowly during a developing situation - several layers of surprise.
However the investigations into training solutions are less convincing - can you ever be really surprise in a simulator - fear. Even if possible can you be sure that everyone has been ‘conditioned’ or will respond appropriately in every ‘surprising’ situation.
Another description of different trim characteristics - https://www.skybrary.aero/bookshelf/books/2627.pdf
Could a 737 operator please confirm that Safety Recommendation 2009-045 (page 4) has be actioned ?
Having decided to fly a GA - the second occasion, perhaps not a significant surprise even though it conflicted with what was planned - expected - hoped for.
A larger surprise effect could emerge from the difference between the lighter weight GA and perhaps slower pitch response in following the FD. A difference in ‘the conditioned expectation of normalcy’.
Also increased or ‘new’ surprise from the unexpected, even unknown automatic change of HUD format to ‘upset’, with additional problems in changing mental focus and assessing the flight path within HUD - previous discussions.
The effect of surprise together with the stick feel/position trim characteristics could have contributed to the excessive nose down pitch response and continued trim operation (‘2.2. On the peculiarities of the trim (relief) of forces’: page 159).
If the 737 is normally flown with the combination of small stick movement, quickly followed up with trim ‘blips’ (note Boeing cautions not to use fly the aircraft with trim). Then depending on personal technique it is possible that with the stress of the situation that the trim blips merge into one, which together with slower pitch response than anticipated - slow speed, high nose up attitude, and max GA thrust, the aircraft is inadvertently flown with trim. If the stick is not centred to judge the effectiveness of trim - reduced stick force, then the aircraft continues to pitch nose down with trim still applied to counter the erroneous stick force from pushing the stick forward.
Recent ref for surprise - https://pure.tudelft.nl/portal/files...on_startle.pdf
Good background on the mechanism and effects of surprise, that it can occur without startle, and build up relatively slowly during a developing situation - several layers of surprise.
However the investigations into training solutions are less convincing - can you ever be really surprise in a simulator - fear. Even if possible can you be sure that everyone has been ‘conditioned’ or will respond appropriately in every ‘surprising’ situation.
Another description of different trim characteristics - https://www.skybrary.aero/bookshelf/books/2627.pdf
Could a 737 operator please confirm that Safety Recommendation 2009-045 (page 4) has be actioned ?
Just a numbered other
Join Date: Apr 2008
Location: back of beyond
Posts: 116
Likes: 0
Received 0 Likes
on
0 Posts
Seems that some lessons have to be re-learnt every now and then.
Last edited by fizz57; 19th Dec 2019 at 07:21.
Join Date: Apr 2008
Location: Middle East
Posts: 29
Likes: 0
Received 0 Likes
on
0 Posts
I lost my job in flydubai for banging the drum about fatigue, the culture there was toxic. This report is incredibly disrespectful to the flight crew who where leaving the company due to the culture and fatigue. People especially the cabin crew would be called into meetings for refusing discretion, calling in fatigued and calling in sick.
Im so glad to be out of there. The report should have investigated the culture of fear. When we had a meeting post crash, the head of OPS who is now running the show said “so we had a crash, crashes happen all the time, get over it” when we asked for a minutes silence in the same meeting to remember those who died the chief pilot started talking 20 seconds into it. Abhorrent.
Despite promising to take care of the crews families, to this day I speak with some of the the crews family members, some are still struggling financially. They where given some money after the crash but only if they signed a piece of paper saying that they wouldn’t sue the company later on when the report came out. Profit over people time and again.
Im so glad to be out of there. The report should have investigated the culture of fear. When we had a meeting post crash, the head of OPS who is now running the show said “so we had a crash, crashes happen all the time, get over it” when we asked for a minutes silence in the same meeting to remember those who died the chief pilot started talking 20 seconds into it. Abhorrent.
Despite promising to take care of the crews families, to this day I speak with some of the the crews family members, some are still struggling financially. They where given some money after the crash but only if they signed a piece of paper saying that they wouldn’t sue the company later on when the report came out. Profit over people time and again.
