787 bounce
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Very droll
For info, here’s the incident;
https://www.gov.uk/aaib-reports/airb...-february-2012
Something that actually happened, compared to your somewhat unlikely scenario....)
Nice to have the AAIB on board, especially with such insight. But did you consider the possibility that all the passengers, seeing the problems the crew were having with gusts, decided to rush forward and advise them how to handle it? Not saying this is the case, but can’t be ruled out....
For info, here’s the incident;
https://www.gov.uk/aaib-reports/airb...-february-2012
Something that actually happened, compared to your somewhat unlikely scenario....)
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No need to press toga immediately, just push the throttles forward and climb away. Toga can be pushed anytime in that sequence. Unless they were on an autoland, but I seriously doubt that.
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Not the only reason Wiggy
During a windshear or gpws event you need maximum performance from the aircraft immediately. The first thing that happens when you raise the gear is the huge gear doors open creating a large amount of extra drag before the gear legs start to move, significantly reducing the available performance. The gear raising process takes approximately ten seconds, during which time your performance is compromised.
During a windshear or gpws event you need maximum performance from the aircraft immediately. The first thing that happens when you raise the gear is the huge gear doors open creating a large amount of extra drag before the gear legs start to move, significantly reducing the available performance. The gear raising process takes approximately ten seconds, during which time your performance is compromised.
Last edited by Locked door; 10th Feb 2019 at 10:42. Reason: Spelling
Not the only reason Wiggy
During a windshear or gpws event you need maximum performance from the aircraft immediately. The first thing that happens when you raise the gear is the huge gear doors open creating a large amount of extra drag before the gear legs start to move, significantly reducing the available performance. The gear raising process takes approximately ten seconds, during which time your performance is compromised.
During a windshear or gpws event you need maximum performance from the aircraft immediately. The first thing that happens when you raise the gear is the huge gear doors open creating a large amount of extra drag before the gear legs start to move, significantly reducing the available performance. The gear raising process takes approximately ten seconds, during which time your performance is compromised.
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No, because an EFATO doesn’t contain an immediately performance critical segment. The perf calculation includes the gear retraction and included in the type certification.
GPWS and windshear are immediate, unique dynamic events with no pre calculations where instantaneous max available performance may be required depending on the severity of the event.
if you don’t believe me, try googling it!
GPWS and windshear are immediate, unique dynamic events with no pre calculations where instantaneous max available performance may be required depending on the severity of the event.
if you don’t believe me, try googling it!
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What happened is the handling pilot flew a textbook rejected landing followed by what looks to be a windshear go-around in tricky conditions. Great job by the guys up front. It
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During a windshear or gpws event you need maximum performance from the aircraft immediately. The first thing that happens when you raise the gear is the huge gear doors open creating a large amount of extra drag before the gear legs start to move, significantly reducing the available performance.
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The gear goes up almost immediately after a positive climb is achieved on a normal go around but stays down until the windshear is exited or positive terrain clearance is achieved ( often above msa) for gpws.
Only half a speed-brake
Midland63 The L/G is kept down during the wind shear escape routine (also) because terrain impact is a possibility. The loads absorbed by the collapsing undercarriage structure make survival of the occupants more likely, any straw counts.
While the doors protruding into the airflow will add drag, and the explanations above that it is accounted for in the EFATO case are sound, the mainstay B737 does not have any on the main landing gear. Go figure? The priority on both GWPS (terrain) and WSHR (loss of lift) scenarios must be to fly the aeroplane up, as the single objective. I gather that history teaches us messing with configuration might be detrimental to the crew's coordinated effort to ensure max thrust is set and peak climb performance is established (with speed-brakes retracted).
My best guess is that avoiding the doors' extra drag applies for GPWS, where the danger of impact is truly immediate. For WSHR, the impact-survival aspect would be the reason, which covers the 737 too. As well you want to keep the procedures simple and similar as much as practicable. What is seen in the video may be better described as a low-level G/A with unavoidable touchdown due to a de-stabilized flare, owing to gust (most likely). The industry standard wind shear model is probably different, though related. Still, the L/G lever is not to be touched!
While the doors protruding into the airflow will add drag, and the explanations above that it is accounted for in the EFATO case are sound, the mainstay B737 does not have any on the main landing gear. Go figure? The priority on both GWPS (terrain) and WSHR (loss of lift) scenarios must be to fly the aeroplane up, as the single objective. I gather that history teaches us messing with configuration might be detrimental to the crew's coordinated effort to ensure max thrust is set and peak climb performance is established (with speed-brakes retracted).
My best guess is that avoiding the doors' extra drag applies for GPWS, where the danger of impact is truly immediate. For WSHR, the impact-survival aspect would be the reason, which covers the 737 too. As well you want to keep the procedures simple and similar as much as practicable. What is seen in the video may be better described as a low-level G/A with unavoidable touchdown due to a de-stabilized flare, owing to gust (most likely). The industry standard wind shear model is probably different, though related. Still, the L/G lever is not to be touched!
Only half a speed-brake
Just realized that opening the NW bay, thus exposing the whell-well into the airflow at higher AoA, might in fact be quite significant.
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The L/G is kept down during the wind shear escape routine (also) because terrain impact is a possibility
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Spot on Flight Detent!
All my Types have the same: Max Pwr NO Config change!
Industry standard for GPWS and Low level Wind Shear escape I gather:
Greenfields
I do disagree, the Gear stays as there is plenty of times the aircraft touches down after a momentary positive climb.( Microburst mostly).
Secondary touchdown with gear in transit will ruin Your day.
Also remember if You have to trade all your airspeed down towards shaker, that gear does not give you much drag as it is the old " Parasite Drag" so it gets less with less speed.
Industry standard for GPWS and Low level Wind Shear escape I gather:
Greenfields
I do disagree, the Gear stays as there is plenty of times the aircraft touches down after a momentary positive climb.( Microburst mostly).
Secondary touchdown with gear in transit will ruin Your day.
Also remember if You have to trade all your airspeed down towards shaker, that gear does not give you much drag as it is the old " Parasite Drag" so it gets less with less speed.
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Overstress I was referring to the Aircraft and the crews action ,not the runway. 27R was in use and all other arrivals seemed normal (some crews nailed it) considering the conditions,those hangers can cause issues in SSW winds.I wish I could post the video of the second approach and landing but unable too.
