B737 Go-Around tragedy. Pilot error all over again
Thread Starter
Perhaps SI affects some pilots and not others? I recall my first night takeoff in the P51 Mustang. At the time I only had 240 hours total time. Now that aircraft really accelerated on take off. I glued my eyes on the artificial horizon and directional gyro once airborne. I certainly don't recall any problems during the initial and subsequent climb which according to my log book was to 15,000 ft.
I have experienced "the leans" in many aircraft but never SI and that includes flying jet transports for decades. I suppose the question needed to be answered if some pilots are more prone to SI than others, could that be proven medically? if so, should they be denied a pilot licence or perhaps restricted to day VMC flying only?
I have experienced "the leans" in many aircraft but never SI and that includes flying jet transports for decades. I suppose the question needed to be answered if some pilots are more prone to SI than others, could that be proven medically? if so, should they be denied a pilot licence or perhaps restricted to day VMC flying only?
I don’t get why this is SI. SI is when horizontal acceleration confuses the balance organs into believing the ac is pitching up. In a GA there is no acceleration and the pitch up is real. I can only talk from 757/767 experience but assume that other Boeings and Airbus have similar logic.
dh, agree.
SI involves acceleration; generally longitudinal, and lesser in non-turning flight while pitching up. A GA contributes little speed change nor great rotation acceleration, usually very short duration and thus insufficient for disorientation.
This appears to to be the reasoning behind the conclusion in the accident investigation.
The pitch - body feel - stick / trim feel aspects could create a different illusion.
I recall that there was a very interesting 757 event during GA where this could have contributed.
SI involves acceleration; generally longitudinal, and lesser in non-turning flight while pitching up. A GA contributes little speed change nor great rotation acceleration, usually very short duration and thus insufficient for disorientation.
This appears to to be the reasoning behind the conclusion in the accident investigation.
The pitch - body feel - stick / trim feel aspects could create a different illusion.
I recall that there was a very interesting 757 event during GA where this could have contributed.
FA.
I get that - that is the actual pitch up which is sensed, not the false illusion created by longitudinal acceleration confusing all those awkward otoliths which weren’t designed for flight.
safety. There are plenty of cocked up GAs in the 757 lifetime!
I get that - that is the actual pitch up which is sensed, not the false illusion created by longitudinal acceleration confusing all those awkward otoliths which weren’t designed for flight.
safety. There are plenty of cocked up GAs in the 757 lifetime!
Last edited by deltahotel; 30th Dec 2019 at 15:06. Reason: Extra added
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We get used to the sensation of pitch from pressure in our back and butt which agree with the ADI. In the real world, with an unexpected acceleration from full TOGA power and a light aircraft - then there can be a sensation / visual mismatch which can cause confusion
Last edited by vilas; 30th Dec 2019 at 17:29.
dh, ‘There are plenty of cocked up GAs in the 757 lifetime!’
and 737 ?
GA Trim ?
https://www.skybrary.aero/bookshelf/books/2627.pdf
and 737 ?
GA Trim ?
https://www.skybrary.aero/bookshelf/books/2627.pdf
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dh, agree.
SI involves acceleration; generally longitudinal, and lesser in non-turning flight while pitching up. A GA contributes little speed change nor great rotation acceleration, usually very short duration and thus insufficient for disorientation.
This appears to to be the reasoning behind the conclusion in the accident investigation.
The pitch - body feel - stick / trim feel aspects could create a different illusion.
I recall that there was a very interesting 757 event during GA where this could have contributed.
SI involves acceleration; generally longitudinal, and lesser in non-turning flight while pitching up. A GA contributes little speed change nor great rotation acceleration, usually very short duration and thus insufficient for disorientation.
This appears to to be the reasoning behind the conclusion in the accident investigation.
The pitch - body feel - stick / trim feel aspects could create a different illusion.
I recall that there was a very interesting 757 event during GA where this could have contributed.
REPORT 7/2003 - Date: 22 January 2003
SERIOUS INCIDENT TO ICELANDAIR BOEING 757-200 AT OSLO AIRPORT GARDERMOEN NORWAY 22 JANUARY 2002
Aircraft type: Boeing 757-208
Registration: TF-FIOOwner:Flugleidir h/f, 101 Reykjavik airport, Reykjavik
Operator: Flugleidir h/f, 101 Reykjavik airport, Reykjavik
Crew: 2/5
Passengers: 75
Incident site: Over RWY 01L at Oslo airport Gardermoen
Date and time of incident: 22 January 2002 at time 1049 hrs.
I'm not allowed to post URLs yet, but I'll gladly PM you the link and maybe you can share it for everyone to read.
Get a hold of this: "the lowest altitude in the recovery was 321 ft radio altitude with a peaked load factor of +3.59 g’s."
Seconds from being another tragedy, just like all these nosing-over in IMC incidents we're reading about. Confused Captain is PF, gets behind the aircraft (due to illusions or whatever other reason), puts the plane in a steep dive; only this time the PM manages to snap him out of it and they both pull for their lives and barely escape before hitting the ground. Some passengers get a glimpse of the earth at the lowest point of the recovery, the cabin is a mess, everybody (except the sheepish flight deck crew) is traumatized for life, but thankfully everyone is alive.
Pretty sure there are some obvious problems that all these incidents and accidents have in common, and that they need to be addressed in training. Urgently.
Thread Starter
In fact GA is considered so mundane that even a report is not required
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https://www.skybrary.aero/index.php/..._2002_(HF_LOC)
Click on the red link.
"When initiating the auto “Go-around”, the auto throttle became engaged, and increased automatically the engine trust to the EPR limit. The application of the under wing engine power also gave a pitch up movement. The flight director pitch bar commanded a pitch attitude of 15o. (The AFDS commanded a level off at 2 500 ft (the last assigned altitude by ATC). The AFDS calculates the high closure rate to 2 500 ft and captures that altitude almost immediately; causing the A/T to change from Go-around mode to retard power to MCP selected speed (150 kt)). The aircraft therefore climbed very rapidly through the MCP selected altitude of 2 500 ft and with the aircraft pitch increasing to 21o. AAIB/N considers that the Commander at this time had lost situational awareness (being “behind the aircraft”).
2.2.3 As the Commander noticed the speed to be rapidly decreasing, he pushed the control column forward. This was in order to follow the command of level off at 2 500 ft. Pushing the control column forward is also an elementary flying procedure to increase the speed and to prevent the aircraft from entering a stall.
2.2.4 The First Officer at this time called for “Bug up”. The Commander reached for and reset the MCP speed. This was contrary to company Standard Operation Procedure. Simultaneously the Commander continued to push the control column even more forward. The aircraft reached a maximum altitude of 2 895 ft and the load factor reached a negative g-value of –0.6.
2.2.5 The aircraft then entered a rapid dive, and the speed increased. Different warnings were given of ground proximity and the command of pull up by the aircraft systems, but not registered by the crew. The A/T reduced the trust from 98% N1 (full power) to 45% N1 (idle power). The negative pitch reached a maximum value nose down of 49o. Up to this time the First Officer had been somewhat passive and confused. Now he acted as an active and co-operative crew member and asked: “What are you doing” and next, he called out: “Pull up!” - “Pull up!”. Both pilots pulled back on their control columns, and the aircraft, after reaching a maximum speed of 251 kt, recovered from the dive with a clearance of 321 ft (radio height) over the north end of the runway 01L. During the pull-up the load factor increased to positive G-value of 3.59."
What common effect causes some disoriented crews to push to 49o nose dow?
Click on the red link.
"When initiating the auto “Go-around”, the auto throttle became engaged, and increased automatically the engine trust to the EPR limit. The application of the under wing engine power also gave a pitch up movement. The flight director pitch bar commanded a pitch attitude of 15o. (The AFDS commanded a level off at 2 500 ft (the last assigned altitude by ATC). The AFDS calculates the high closure rate to 2 500 ft and captures that altitude almost immediately; causing the A/T to change from Go-around mode to retard power to MCP selected speed (150 kt)). The aircraft therefore climbed very rapidly through the MCP selected altitude of 2 500 ft and with the aircraft pitch increasing to 21o. AAIB/N considers that the Commander at this time had lost situational awareness (being “behind the aircraft”).
2.2.3 As the Commander noticed the speed to be rapidly decreasing, he pushed the control column forward. This was in order to follow the command of level off at 2 500 ft. Pushing the control column forward is also an elementary flying procedure to increase the speed and to prevent the aircraft from entering a stall.
2.2.4 The First Officer at this time called for “Bug up”. The Commander reached for and reset the MCP speed. This was contrary to company Standard Operation Procedure. Simultaneously the Commander continued to push the control column even more forward. The aircraft reached a maximum altitude of 2 895 ft and the load factor reached a negative g-value of –0.6.
2.2.5 The aircraft then entered a rapid dive, and the speed increased. Different warnings were given of ground proximity and the command of pull up by the aircraft systems, but not registered by the crew. The A/T reduced the trust from 98% N1 (full power) to 45% N1 (idle power). The negative pitch reached a maximum value nose down of 49o. Up to this time the First Officer had been somewhat passive and confused. Now he acted as an active and co-operative crew member and asked: “What are you doing” and next, he called out: “Pull up!” - “Pull up!”. Both pilots pulled back on their control columns, and the aircraft, after reaching a maximum speed of 251 kt, recovered from the dive with a clearance of 321 ft (radio height) over the north end of the runway 01L. During the pull-up the load factor increased to positive G-value of 3.59."
What common effect causes some disoriented crews to push to 49o nose dow?
What common effect causes some disoriented crews to push to 49o nose down?
Only half a speed-brake
Just wondering why "speed tape confusion" does not get any mention in these, unfortunately recent, discussions.
Together with a reduced/negative G confusion and the improper trimming technique (explained in the Rostov report).
In other words, combined with a high-rate trim with flaps out and possible TE auto-retraction, the pushovers once the brain trails behind the A/C are almost inevitable - in the absence of visible horizon if you are a human.
Together with a reduced/negative G confusion and the improper trimming technique (explained in the Rostov report).
In other words, combined with a high-rate trim with flaps out and possible TE auto-retraction, the pushovers once the brain trails behind the A/C are almost inevitable - in the absence of visible horizon if you are a human.
Last edited by FlightDetent; 31st Dec 2019 at 12:59.
Stuka Child, thanks.
That was the specific incident, however we should not jump to any conclusion just because there appears to be many events. Aircraft type specific, rarity of event, different training, … but no smoke without fire.
- - -
Accidents usually involve a combination of issues, different aspects of disorientation - conflicting spatial senses. The stick force issue might contribute via the points in OP #1, what pilots feel in relation to what is seen - IFR manual instrument flight. This aspect of force can be demonstrated / experienced in simulators; - to what extent do pilots use stick force in forming the ‘big picture’ when manoeuvring aircraft.
From an old 737 (classic?) incident: fuel cross-feed balancing selected, overlooked by distraction, route change, the AP had difficulty in turning. The crew disengaged the AP, falsely judged roll control with respect the mis-trimmed, unbalance lateral stick feel, the aircraft rolled thought 90 deg with crew holding zero force - stick offset creating roll. N.B. lateral trim may not exhibit the same characteristics as pitch trim.
Pilots may be unfamiliar with situations which require flight with offset stick force, having to ignore the haptic sense and concentrate on the instruments - vision is the primary sense.
Golden, a potential ‘common’ contribution is misuse of trim in those aircraft with susceptible systems; see link in # 27. The amount of nose down is not important; the issue is that the nose is pointing down, and why.
e.g. a GA involving a high nose up pitching moment - low engines, max thrust. If the compensating stick forward control continues to be held forward, and still trimming with the expectation that trim will result in zero stick force, then it is conceivable that over correction will continue to lower the nose and the trim positioned nose down, effectively controlling the aircraft. These aircraft require that the stick is moved towards centre to identify in-trim conditions, whereas other trim systems will reduce stick force at the existing control position.
That was the specific incident, however we should not jump to any conclusion just because there appears to be many events. Aircraft type specific, rarity of event, different training, … but no smoke without fire.
- - -
Accidents usually involve a combination of issues, different aspects of disorientation - conflicting spatial senses. The stick force issue might contribute via the points in OP #1, what pilots feel in relation to what is seen - IFR manual instrument flight. This aspect of force can be demonstrated / experienced in simulators; - to what extent do pilots use stick force in forming the ‘big picture’ when manoeuvring aircraft.
From an old 737 (classic?) incident: fuel cross-feed balancing selected, overlooked by distraction, route change, the AP had difficulty in turning. The crew disengaged the AP, falsely judged roll control with respect the mis-trimmed, unbalance lateral stick feel, the aircraft rolled thought 90 deg with crew holding zero force - stick offset creating roll. N.B. lateral trim may not exhibit the same characteristics as pitch trim.
Pilots may be unfamiliar with situations which require flight with offset stick force, having to ignore the haptic sense and concentrate on the instruments - vision is the primary sense.
Golden, a potential ‘common’ contribution is misuse of trim in those aircraft with susceptible systems; see link in # 27. The amount of nose down is not important; the issue is that the nose is pointing down, and why.
e.g. a GA involving a high nose up pitching moment - low engines, max thrust. If the compensating stick forward control continues to be held forward, and still trimming with the expectation that trim will result in zero stick force, then it is conceivable that over correction will continue to lower the nose and the trim positioned nose down, effectively controlling the aircraft. These aircraft require that the stick is moved towards centre to identify in-trim conditions, whereas other trim systems will reduce stick force at the existing control position.
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e.g. a GA involving a high nose up pitching moment - low engines, max thrust. If the compensating stick forward control continues to be held forward, and still trimming with the expectation that trim will result in zero stick force, then it is conceivable that over correction will continue to lower the nose and the trim positioned nose down, effectively controlling the aircraft. These aircraft require that the stick is moved towards centre to identify in-trim conditions, whereas other trim systems will reduce stick force at the existing control position.
