111–120 of 469 posts
Another DC-10/MD-11 crash. Does UPS perform their own engine maintenance, or do they outsource the work? What is the effect of the recent layoff of 40,000 and the current cost-cutting project?
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Unless you have a berm several dozen meters high with a 100 meter base, you ain't stopping something like this from a physics standpoint unfortunately. Many airports have this problem. The recent korean air disaster which echos this is another example. BTW, this is why most airports, if possible, point out to sea...
There is a dead zone between rejection and successful take-off speeds. We see it hit too often. I think pilot training is playing a factor. A normal rotation kills too much energy. One engine can climb when you have some airspeed and get clean, but if you lose too much energy on rotation, the inefficiency of the AoA for the rest of the short flight means that engine can no longer buy you any up. I've seen too many si…
I'm skeptical whether pilots can realistically make this kind of decision, given that they have no more than a few seconds to make it, and in cases such as this based on very incomplete information about the state of their aircraft.
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Could they add cameras to solve this issue?
During engine failure / fire situations, I would expect that pilots are likely to be too busy to have any time left over for peering at a video feed, trying to assess the state of the wing. In emergencies, information overload tends to make things worse, not better.
And now we have technology that allows for cameras everywhere to give a better situational awareness across all critical aircraft surfaces and systems.
It is going to take a little bit of adjusting to, but it will help improve safety in a tremendous way.
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One improvement is a bed of concrete at the end of the runway that will catch the wheels and slow an airplane down to a stop. Pretty much everyone agrees it’s a good idea but it’s not always possible due to space needs or cost. https://en.wikipedia.org/wiki/Engineered_materials_arrestor_...
If it costs too much it is also a bad idea. Why? Because that money can be spent on other safety.
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During engine failure / fire situations, I would expect that pilots are likely to be too busy to have any time left over for peering at a video feed, trying to assess the state of the wing. In emergencies, information overload tends to make things worse, not better.
Having cameras pointed at the engines/wings like rearview mirrors would be helpful. It does not add that much workload if you take a quick glance in the “mirror” and figure out what the problem exactly is. And now we have technology that allows for cameras everywhere to give a better situational awareness across all critical aircraft surfaces and systems. It is going to take a little bit of adjusting to, but it will…
And how would the cameras even work? Are the pilots supposed to switch between multiple camera feeds, or do we install dozens of screens? And then what, they see lots of black smoke on one camera, does that really tell them that much more than the ENG FIRE alert blaring in the background?
Maybe this could help during stable flight, but in this situation, when the pilots were likely already overloaded and probably had only a few seconds to escape this situation - if it was possible at all - I can't imagine it being helpful.
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You're 100% right, and that's exactly what I'm getting at - they hit V1 and were aware they had a serious problem, but couldn't abort. As far as the rest of my comment - watch the videos that I linked.
Could they have not hit V1 but decided to take off anyway to minimise damage (i am guessing the reverse thrust might be impossible to stop?)
After V1 you must be able to take off on only the remaining engines. If that's not possible you must reduce weight until it is possible or you're not allowed to start takeoff at all.
This is why in very warm weather and higher altitude airports (lower performance) sometimes cargo/luggage or even some passengers are left behind, while in colder weather all seats could be used.
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Well, there's a very big difference between "Engine fire: some of the combustion chamber's heat and flame has breached containment" and, say, "Engine fire: the engine has exploded, catastrophically damaging your wing which is now visibly on fire". However, both things are reported in the cockpit as ENG FIRE. There's also a very big difference between "Engine failure: something has damaged or jammed enough components…
Could they add cameras to solve this issue?
Now... not sure how much that is helpful in this kind of emergency, they really didn't have time to do much.
This is probably the worst way a plane could go down in terms of damage caused. Maximum effect in term of damage. Cargo plane apparently reached V1 (go/no go speed) on the runway, and suffered a catastrophic engine failure. They passed V1, so they knew they were going down. Engine was shedding large debris, including the housing (!!!) which is a shrapnel shield. They were on fire just as they reached V1. Plane was fu…
>> highway and warehouses at the end of the runway It's astonishing that this is a thing. Why aren't we building airports with enough space for a plane to remain on the ground and have plenty of room to decelerate in this situation? I can understand why it can't be retro fitted to existing airports but is it a scenario that's considered at new airports? Just seems like such an absolutely basic safety step.
Airports also grow themselves. Some municipal airports sited for small aircraft extend their runways to handle larger planes.
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V1 is the speed at which you can still stop the plane before the end of the runway. (It is computed for each takeoff based on runway length, aircraft mass, takeoff engine power setting, flaps, wind, runway condition, etc.) When the plane reaches V1, pilots take the hand off the throttle: they're committed to takeoff, even if an engine fails. It is better to take off and fix the problem or land again, than to smash in…
Isn't there any margin? Does it calculate stopping before end of runway or before causing damage? Surely uncertainty about the situation contributes to defaulting to committing, but what if it's a passenger plane and at V1 pilots know they've lost power? Wouldn't veering into highway at 30 mph be weighted against certain, big loss of life? Edit: I now see that this has been partially answered by uncle comment
The margin is for example that the plane must not just be able to fly, but also reach a minimum climb gradient to clear obstacles with a bit of safety margin. There is also an allowance for the time it takes from calling abort to actually hitting the brakes. And for example headwind is part of the calculation (it makes the takeoff distance shorter) but only 50% of the headwind is used in the calculations.
But all of those margins are not for the crew to use, the crew must just execute the procedure exactly as trained which means at V1 you're committed to continue the takeoff. And before V1 in case of an engine failure you have to hit the brakes to make sure you can stop before the end of the runway.
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> The crew wouldn't have had any way to know that one of their engines had not simply failed, but was straight-up gone with their wing on fire to boot. I don't know about the MD-11 itself, but other aircraft from that time period have sensors to detect and report overheat and fire in various parts of the aircraft, including engines and wings.
Well, there's a very big difference between "Engine fire: some of the combustion chamber's heat and flame has breached containment" and, say, "Engine fire: the engine has exploded, catastrophically damaging your wing which is now visibly on fire". However, both things are reported in the cockpit as ENG FIRE. There's also a very big difference between "Engine failure: something has damaged or jammed enough components…
What is the difference?