Final report on CX780 accident published
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There is no doubt that this crew did a fabulous job. They were thinking pretty far ahead considering the number of surprises that the aircraft threw at them.
In my reading of the accident report, there is one thing that stands out to my tactical pilot eye, the use of the speed brakes.
Since I've never flown the type, I figured I'd ask some of you who have experience in the type.
I can understand the pilot's wish to keep the aircraft in a configuration that he had experienced before, thus retracting the speed brakes and arming the ground spoilers, but in this case, given an aproach ~95 knots faster than the usual, with the Flaps 1 selection aerodynamically limited, was it necessary to retract the speed brakes?
If the speed brakes had remain deployed, is it likely that the aircraft would not have had such an ungainly bounce which delayed activation of the spoilers and commencement of braking (as well as overstressing the nose and left main landing gear and scraping the #1 pod)?
I am not asking these questions with any intent to be critical of this crew, who handled a difficult situation with great professionalism. I am asking to see if there is anything else from this accident that might be learned, and to at least answer my own curiosity.
Prior to the date of this incident, had anyone received training in a similar type of dual engine problem scenario? It seems to me that a training scenario like this would likely be considered low probability and thus not given training emphasis.
In my reading of the accident report, there is one thing that stands out to my tactical pilot eye, the use of the speed brakes.
Since I've never flown the type, I figured I'd ask some of you who have experience in the type.
From the accident report:
m. At 0540 hrs, Hong Kong Approach cleared CPA780 for a visual approach for Runway 07L. Flight crew deployed the speedbrakes when the aircraft was at 5,216 ft AMSL descending with a CAS of 234 kt at around 8 nm from VHHH. Flight crew selected landing gear down shortly afterwards.
n. The Commander aimed to fly the aircraft at a CAS as close as possible to the Minimum Selectable Speed (VLS), which was 158 kt at that time. The aircraft went through the runway extended centreline and recaptured the centreline from the north in order to manage altitude and airspeed. Landing checklist was actioned. At around 0541 hrs, with the Maximum Allowable Speed (Vmax) at 240 kt and actual CAS at 244 kt, an overspeed warning was generated by the onboard system. A short while later Hong Kong Approach cleared CPA780 to land on Runway 07L and advised that the current surface wind was 150 degrees at 13 kt. Flight crew stowed the speedbrakes when the aircraft was at 984 ft AMSL and armed the ground spoilers at 816 ft AMSL.
m. At 0540 hrs, Hong Kong Approach cleared CPA780 for a visual approach for Runway 07L. Flight crew deployed the speedbrakes when the aircraft was at 5,216 ft AMSL descending with a CAS of 234 kt at around 8 nm from VHHH. Flight crew selected landing gear down shortly afterwards.
n. The Commander aimed to fly the aircraft at a CAS as close as possible to the Minimum Selectable Speed (VLS), which was 158 kt at that time. The aircraft went through the runway extended centreline and recaptured the centreline from the north in order to manage altitude and airspeed. Landing checklist was actioned. At around 0541 hrs, with the Maximum Allowable Speed (Vmax) at 240 kt and actual CAS at 244 kt, an overspeed warning was generated by the onboard system. A short while later Hong Kong Approach cleared CPA780 to land on Runway 07L and advised that the current surface wind was 150 degrees at 13 kt. Flight crew stowed the speedbrakes when the aircraft was at 984 ft AMSL and armed the ground spoilers at 816 ft AMSL.
If the speed brakes had remain deployed, is it likely that the aircraft would not have had such an ungainly bounce which delayed activation of the spoilers and commencement of braking (as well as overstressing the nose and left main landing gear and scraping the #1 pod)?
I am not asking these questions with any intent to be critical of this crew, who handled a difficult situation with great professionalism. I am asking to see if there is anything else from this accident that might be learned, and to at least answer my own curiosity.
Prior to the date of this incident, had anyone received training in a similar type of dual engine problem scenario? It seems to me that a training scenario like this would likely be considered low probability and thus not given training emphasis.
Per Ardua ad Astraeus
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No type experience and extreme reluctance to 'unpick' an excellent piece of flying from the benefit of my armchair in a situation I would have dreaded to find myself. However, since you have asked, my take:-
Yes, speedbrake would have helped dissipate the excess energy
I suspect it was 'stowed' for 2 reasons:-
1) We do not practice flaring and touching down with them deployed, so that would be an 'unknown', and the potential sink rates, possible change in pitch response and the buffet would have been dramatic and possibly disconcerting
2) It is driven into us that speedbrake must not be deployed below 1000', and with everything else they were handling at that time, it could have been an 'automatic' understandable reaction.
Yes, speedbrake would have helped dissipate the excess energy
I suspect it was 'stowed' for 2 reasons:-
1) We do not practice flaring and touching down with them deployed, so that would be an 'unknown', and the potential sink rates, possible change in pitch response and the buffet would have been dramatic and possibly disconcerting
2) It is driven into us that speedbrake must not be deployed below 1000', and with everything else they were handling at that time, it could have been an 'automatic' understandable reaction.
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JPJP - you said:
"A/P on at 1144'. Daytime departure.
Ha
Yeah. I noticed that. Perhaps the FO had been hand flying the aircraft so much he decided that some automation familiarization was in order ...."
JPJP, you were being condescending. Nice try wriggling out of it though.
"A/P on at 1144'. Daytime departure.
Ha
Yeah. I noticed that. Perhaps the FO had been hand flying the aircraft so much he decided that some automation familiarization was in order ...."
JPJP, you were being condescending. Nice try wriggling out of it though.
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I know some aircraft types have had tailstrikes when accidentally landing with speedbrakes deployed. However, if this situation were to happen on a shorter runway, it might be better than an overrun.
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Speed brakes
Dont they are hinibited to deploy if you have power setting above idle?
Then my question is why engine one was not takent out the line by arming and eventually discharging the fire extinguish system? Asymmetric reverse thrust is recommended in similar events?
Good job crew anyway . A good happy ending story
Then my question is why engine one was not takent out the line by arming and eventually discharging the fire extinguish system? Asymmetric reverse thrust is recommended in similar events?
Good job crew anyway . A good happy ending story
Last edited by ZAGORFLY; 16th Sep 2013 at 04:23.
That engine was still supplying hydraulic power to the green system, so why on earth would you shut it down in a situation where control of the aircraft was already compromised by "stuck" thrust on # 2.
