A380 gear down across the Atlantic
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Joined: Jul 2023
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From: London
A380 gear down across the Atlantic
https://simpleflying.com/global-airlines-everything-we-know-so-far/
This is a pure technical question out of curiosity:
Does anyone have any information or thoughts about the brakes/gear in this scenario? Gear down after take off for a bit to cool the brakes is one scenario. But cold-soaking the brake discs for several hours and then landing - what would the effect be?
In the reverse sense; cooling hot metal too quickly can warp it. Does heating cold metal have a similar effect?
Rick
This is a pure technical question out of curiosity:
Does anyone have any information or thoughts about the brakes/gear in this scenario? Gear down after take off for a bit to cool the brakes is one scenario. But cold-soaking the brake discs for several hours and then landing - what would the effect be?
In the reverse sense; cooling hot metal too quickly can warp it. Does heating cold metal have a similar effect?
Rick
Joined: Dec 2003
Posts: 2,338
Likes: 821
From: Tring, UK
1) The gear wells are neither heated nor pressurised in any aircraft I know of, so although the gear would cool down more quickly if left extended, the end result would be the same: temperature close to the average TAT in the cruise. It would actually warm up quicker in the descent, so the brakes could be at a higher temperature than normal on landing. Anyway, no real effect.
2) A gear-down ferry flight is severely limited by the extra drag. This reduces the aircraft ceiling, increases fuel flow and cuts the range down considerably, possibly by 50% or more and can also reduce the maximum takeoff weight if the gear cannot be retracted following an engine failure, so everything is working against you. Fairly unusual to do a long sector with the wheels down - it’s normally a hop to the nearest place where it can be fixed.
2) A gear-down ferry flight is severely limited by the extra drag. This reduces the aircraft ceiling, increases fuel flow and cuts the range down considerably, possibly by 50% or more and can also reduce the maximum takeoff weight if the gear cannot be retracted following an engine failure, so everything is working against you. Fairly unusual to do a long sector with the wheels down - it’s normally a hop to the nearest place where it can be fixed.
Joined: Nov 1999
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From: UK
We once ferried an empty A330 with the gear locked down* from Florida to Goose Bay, Canada, (where we needed to refuel before the Atlantic hop, owing to the increased drag.)
Gear-down ferry on that type is limited to FL250 and 250 kts, and we noticed no ill effects on the tyres or brakes on landing or taxiing in. I cannot remember seeing any untoward brake temperature readings.
* owing to a a landing gear fault.
Gear-down ferry on that type is limited to FL250 and 250 kts, and we noticed no ill effects on the tyres or brakes on landing or taxiing in. I cannot remember seeing any untoward brake temperature readings.
* owing to a a landing gear fault.
Joined: Sep 2004
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From: Canada
Just curious
Were you limited to 250 IAS or TAS? I assume IAS. so +- 350TAS? You would have fit in well with all the C-130 traffic.
Were you limited to 250 IAS or TAS? I assume IAS. so +- 350TAS? You would have fit in well with all the C-130 traffic.
We once ferried an empty A330 with the gear locked down* from Florida to Goose Bay, Canada, (where we needed to refuel before the Atlantic hop, owing to the increased drag.)
Gear-down ferry on that type is limited to FL250 and 250 kts, and we noticed no ill effects on the tyres or brakes on landing or taxiing in. I cannot remember seeing any untoward brake temperature readings.
* owing to a a landing gear fault.
Gear-down ferry on that type is limited to FL250 and 250 kts, and we noticed no ill effects on the tyres or brakes on landing or taxiing in. I cannot remember seeing any untoward brake temperature readings.
* owing to a a landing gear fault.
Joined: Feb 2002
Aviation Qualifications: AME
Posts: 4,166
Likes: 1,096
From: UK
https://simpleflying.com/global-airlines-everything-we-know-so-far/
This is a pure technical question out of curiosity:
Does anyone have any information or thoughts about the brakes/gear in this scenario? Gear down after take off for a bit to cool the brakes is one scenario. But cold-soaking the brake discs for several hours and then landing - what would the effect be?
In the reverse sense; cooling hot metal too quickly can warp it. Does heating cold metal have a similar effect?
Rick
This is a pure technical question out of curiosity:
Does anyone have any information or thoughts about the brakes/gear in this scenario? Gear down after take off for a bit to cool the brakes is one scenario. But cold-soaking the brake discs for several hours and then landing - what would the effect be?
In the reverse sense; cooling hot metal too quickly can warp it. Does heating cold metal have a similar effect?
Rick
Joined: Apr 2004
Posts: 2,166
Likes: 86
From: Planet Earth
My dear Dad flew the Britannia in the RAF, on one occasion he had to perform a gear down ferry flight across the US
He mentioned how despite being restricted to their gear limit speed they were still going faster than the DC4s and other piston airliners of the time
He mentioned how despite being restricted to their gear limit speed they were still going faster than the DC4s and other piston airliners of the time
Joined: Nov 1999
Aviation Qualifications: ATPL
Posts: 3,140
Likes: 740
From: UK
I should have added that we didn't fly across the Atlantic in that A330 that day because after landing to refuel, we had concerns about the integrity of the gear - even though it was locked down - so we called the engineers again, who eventually changed the whole port main gear leg. We went home and another crew later went out to fly the A330 home.
