A hasty go-around. Easy to be wise after the event
https://www.skybrary.aero/index.php/...no_Italy,_2008
Sometimes a hasty decision works out OK. Other times it doesn't. This is one occasion when a hasty decision (startle effect is the new buzzword) was wrong. Being wise after the event is another way of looking at it. |
Present level of flight safety to some extent is the result of being wise after events so there absolutely nothing wrong with that. If pilots were to learn everything from their own experience they may not live that long. By all accounts the decision to go around at less than 136ft because of birds was without any thought process involved. Call it startle or whatever it goes without saying was inappropriate, even if it would have worked. A slight delay in hitting TOGA would have brought them flare height. It was like reject takeoff after V1. It
can happen lucky to get away. So below certain height if stabilized there has to be a predetermination to land without thinking. |
Originally Posted by vilas
(Post 10563047)
Present level of flight safety to some extent is the result of being wise after events so there absolutely nothing wrong with that. If pilots were to learn everything from their own experience they may not live that long. By all accounts the decision to go around at less than 136ft because of birds was without any thought process involved. Call it startle or whatever it goes without saying was inappropriate, even if it would have worked. A slight delay in hitting TOGA would have brought them flare height. It was like reject takeoff after V1. It
can happen lucky to get away. So below certain height if stabilized there has to be a predetermination to land without thinking. |
Originally Posted by semmern
(Post 10563062)
Really? What about a CAT III a/p failure in the flare? |
A slight delay in hitting TOGA would have brought them flare height. It was like reject takeoff after V1. The guidance mentioned in the report "Birdstrike Threat Awareness" says, "VII.2 At Landing • On short final, do not go around, if birds are encountered, but fly through the bird flock and land. Try to maintain a low thrust setting. • The use of reverse thrust on landing after a birdstrike should be avoided. It may increase engine damage, especially when engine vibration or high EGT are indicated." Pity - that crew hadn't read it. |
Bear in mind this was from 2008 and there have been many advances in the technical and HP&L arenas since then.
There you are on short finals as captain and PM and you see a massive (>1,000 according to the report) flock of birds. After you’ve made the decision to avoid them, communicated it to the PF (who hasn’t seen them), the PF has overcome his startle reaction and commenced a GA, you fly into it. Shortly after, both engines suffer severe damage making a descent and landing the only option. This is an unpleasant situation to be in, not least because of the multiple reversals of intent over a short timescale: first landing, then GA, then forced landing. Coordinating something like that is a tricky CRM problem which doesn’t get practiced much, if at all, so it is no surprise that it went a bit pear shaped. That said, the aircraft got a bit bent but everyone inside lived, which for a double engine failure could be said to be a good result. Yes, you could argue that there might have been a better result if the captain (or FO, had he been PM in a similar situation) had immediately taken control and gone around, then informed the other pilot why but guidance on bird encounters only came out *after* this event. The accident was severe enough to trigger thorough investigation from all angles, leading to improved/new procedures and training but not so severe as to seriously injure or kill anyone. One might actually call that progress. Pity - that crew hadn't read it. |
Interesting read. How signifiant is it that they had switched off A/T, AP and FD? Would an Airbus 'alpha floor' type of protection have prevented the stall and flop and resulted in a more controlled return to earth after the odd decision to attempt a go around with engines full of dead birds ?
|
Alpha floor is an auto thrust function (but does not require AT to be active). If you fly through a bunch of birds and the engines flame out, alpha floor will do nothing for you. |
Hi FullWings,
but guidance on bird encounters only came out *after* this event. https://skybrary.aero/bookshelf/books/181.pdf |
Yes but they were in a 737...
|
Originally Posted by AerocatS2A
(Post 10563178)
Alpha floor is an auto thrust function (but does not require AT to be active). If you fly through a bunch of birds and the engines flame out, alpha floor will do nothing for you. |
Originally Posted by vilas
(Post 10563047)
Present level of flight safety to some extent is the result of being wise after events so there absolutely nothing wrong with that. If pilots were to learn everything from their own experience they may not live that long. By all accounts the decision to go around at less than 136ft because of birds was without any thought process involved. Call it startle or whatever it goes without saying was inappropriate, even if it would have worked. A slight delay in hitting TOGA would have brought them flare height. It was like reject takeoff after V1. It
can happen lucky to get away. So below certain height if stabilized there has to be a predetermination to land without thinking. |
Originally Posted by double_barrel
(Post 10563189)
Ah. I had misunderstood, thought it gave you full power but also limited AoA to give steepest possible climb.
|
Originally Posted by Goldenrivett
(Post 10563144)
I disagree. It's nothing like rejecting take off after V1 - it is a recognised procedure called "Balked Landing".
The guidance mentioned in the report "Birdstrike Threat Awareness" says, "VII.2 At Landing • On short final, do not go around, if birds are encountered, but fly through the bird flock and land. Try to maintain a low thrust setting. • The use of reverse thrust on landing after a birdstrike should be avoided. It may increase engine damage, especially when engine vibration or high EGT are indicated." Pity - that crew hadn't read it. |
Originally Posted by ironbutt57
(Post 10563237)
it does, but cannot do so IF THE ENGINES ARE FLAMED OUT
|
Angle of attack protections are different from alpha floor. Airbus type flight protections will go some way toward ensuring that the crash is controlled rather than fully stalled. |
See AF276 at Habsheim...
|
Originally Posted by AerocatS2A
(Post 10563273)
Angle of attack protections are different from alpha floor. Airbus type flight protections will go some way toward ensuring that the crash is controlled rather than fully stalled. |
Originally Posted by vilas
(Post 10563299)
With engines flamed out in alternate law there is no alpha floor or AoA protection if you pull up you will be in full stall.
|
Originally Posted by vilas
(Post 10563092)
Isn't your question superfluous? Just because you would go around in CAT3 with Flare mode failure you would like to go around in visual with a flock of birds at 100ft? I can only hope I am not among passengers.
|
Originally Posted by vilas
(Post 10563047)
So below certain height if stabilized there has to be a predetermination to land without thinking.
200ft, because that is Alert Height for an Auto Land? 100ft, even if there is a runway incursion? 50ft, even though I over flared and will not touchdown within landing zone triggering a long landing event? 10ft, after I slam in on and have a high bounce, even though Airbus say in that event I should go around? My manual says I can Go Around up until I select REV THR. |
Yes but they were in a 737... That said, I agree with FullWings. This accident has been done to death. Everyone has learnt something. It was a good recovery after the engine failure(s) and none was killed. Not sure what alpha floor, or autopilot mode, discussions will further lead to. |
It's in the 737 FCTM as well. An excerpt from the amendment introduced in the FCTM Boeing B737, issued after the present event, is shown below. |
Yes, it is *now* but to quote from the official report: |
Originally Posted by The Shovel
(Post 10563338)
So at what altitude do you suggest I stop thinking and just land?
200ft, because that is Alert Height for an Auto Land? 100ft, even if there is a runway incursion? 50ft, even though I over flared and will not touchdown within landing zone triggering a long landing event? 10ft, after I slam in on and have a high bounce, even though Airbus say in that event I should go around? My manual says I can Go Around up until I select REV THR. |
Towards what vilas is trying to say: there's the 400 feet no action rule too...
|
Thanks FD. May be I should have written my post differently. What you said already exists, add even birds sighting to that.
|
Sometimes a hasty decision works out OK. Other times it doesn't. This is one occasion when a hasty decision (startle effect is the new buzzword) was wrong. Being wise after the event is another way of looking at it. As an example: A 737-200 crew experienced a flashing of the Wing Body Overheat light while taxiing for take off on a short (5600 ft) sea level tropical island in the Central Pacific region. The WBO light extinguished three minutes before the takeoff roll commenced. The captain briefed that if the WBO light came on again below 80 knots he would abort and above 80 knots the take off would be continued according to the FCTM advice and the problem would be sorted out in the air. There was no runway end safety area - only a cliff into the sea 30 metres off the end of the runway. At approximately 10 knots below V1, the Master Caution light illuminated along with the WBO annunciator light. The captain immediately rejected the takeoff catching the first officer as PM by surprise. Such was the drama, the captain not only forgot to manually select spoilers up but the first officer was so startled (horrified is a better description) he forgot to warn the captain of no speed brakes. Full reverse had been applied by the captain. The aircraft stopped right on the end of the runway and after regaining his composure, the captain taxied to the tarmac and shut down the engines. The F/O then asked the captain why he, contrary to his earlier takeoff safety briefing, had aborted the take off. The captain was perfectly honest in his reply, saying " I haven't got a clue - it was an instantaneous knee-jerk decision made when the Master Caution illuminated directly in front of my eyes." The second example of startle factor was a Viscount taking off on a long runway. The aircraft was light but the runway was damp from recent rain. On line-up the crew saw hundreds of birds on the runway apparently feeding off tiny worms. The crew delayed the departure while fire and rescue crews hosed the birds off the runway. During the takeoff run and at V1 many birds were seen to arise from the grass adjacent to the runway edges and fly directly into the Viscount. Multiple bird strikes occurred. The pilot immediately aborted the takeoff fearing the possibility of bird ingestion into the engines. With ample length of runway remaining the Viscount was stopped without heavy braking and taxied to the tarmac. Engineers inspected the aircraft discovering evidence of bird strikes. The engines were ground-run and found serviceable. The aircraft then departed. Earlier, 24 dead birds were found on the runway. In his statement, the pilot said he was aware that the runway was twice the length needed for takeoff and this influenced his decision to reject the takeoff at high speed above V1 as he had no knowledge of any damage caused by the multiple bird strikes or if birds had been ingested by the engines which may fail seconds after lift-off. |
All times are GMT. The time now is 11:03. |
Copyright © 2024 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.