knot4u
Repeat Offender
Agreed.
American 767 RTO at ORD
- Thread starter Colin Levy
- Start date
T/O w/FSII
Well-Known Member
THROUGH the roof. A UPS employee said he heard it hit the floor and it was still hot and smoldering when he found it.
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Roger Roger
Bottom of the list
Now THATS a story!
T-Swift
Well-Known Member
Help me out here, can we see the initial fracture in this picture? I'm a bit naive when it comes to this.
Also, it surely seems like that was plenty of runway as they still had 3-4K of runway left after the stop. Why not use full length every time? Can you even if op specs don't call for it?
Roger Roger
Bottom of the list
The black area just above the ruler is the fatigue fracture. That crack existed for a while and the fretting between crack surfaces created the discoloration. The rough gray area is where it failed suddenly in overload.
Help me out here, can we see the initial fracture in this picture? I'm a bit naive when it comes to this.
Also, it surely seems like that was plenty of runway as they still had 3-4K of runway left after the stop. Why not use full length every time? Can you even if op specs don't call for it?
BlueMoon
Well-Known Member
Help me out here, can we see the initial fracture in this picture? I'm a bit naive when it comes to this.
Also, it surely seems like that was plenty of runway as they still had 3-4K of runway left after the stop. Why not use full length every time? Can you even if op specs don't call for it?
Im not sure if you're asking about using the full length to stop or starting the T/O from the full length. I think they did an intersection T/O and that is up to the PIC. Perfectly acceptable to ask for full length if she/he wishes.
As for using he extra runway for stopping, you just don't leave anything to chance, you want to get it stopped ASAP. You know you have a major problem, and you have no idea what else is wrong, you could lose brakes, tires, hydraulics, steering, or end up with smoke coming in the cabin. The QRH or memory items at all shops I have been at were max braking until a safe stop for an RTO. You would hate to let up on the brakes, get near the end and then find out you have compromised stopping ability , steering problems, or you under estimated your speed and now are going to too fast to stop.
Get it stopped, get CFR on it, and get the people off if necessary.
They were most likely using auto brakes and the RTO/MAX setting for T/O will get you stopped in a hurry.
Also, you might not know you have any margin for stopping. Yes they did stop with 3-4000ft remaining, but I don't know if they get that information of extra stop margin in their take off data. They may have had no extra distance and it was merely because it happened well before V1 that they stopped well before the end.
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Help me out here, can we see the initial fracture in this picture? I'm a bit naive when it comes to this.
Also, it surely seems like that was plenty of runway as they still had 3-4K of runway left after the stop. Why not use full length every time? Can you even if op specs don't call for it?
You can see the dark lined areas and spolch, different from the "clean" metal separation/tear areas that were the result of the cracking finally giving way.
T-Swift
Well-Known Member
Sorry, I meant use full length for TO every time.
A good discussion here on RTO philosophy, involving an accident where there was a ton of runway available, and the crew did a successful RTO electing to rollout, vice try to max brake on possibly damaged trucks following tire failure. Other damage eventually caused further problems for them.
http://forums.jetcareers.com/threads/when-mr-murphy-rides-in-your-jumpseat.91792/#post-1238803
BobDDuck
Island Bus Driver
Because there is no need to. Takeoff data gives you sufficient runway to accelerate and go or accelerate and stop. You've got to trust the data.
We do lots of things that aren't the most safe possible solution in aviation, but somebody has done a risk/reward analysis on it and deemed it a worth of the risk.
While true, i still think that for something like takeoff, there's little reward/gain, for the risk being taken. The numbers are best case, assuming parameters and assumptions are met in an RTO initiation. Runway behind you is wasted space, with little to gain from leaving it behind you. Unlike, for example, not tankering fuel; where there's a real gain made there for little risk of flying computed fuels + reserves.
Flying pax from Pt A to Pt B , isn't akin to trying to launch for survival in a B-52 when nukes are inbound. Which to me, is why leaving runway behind you in a large aircraft, is a healthy amount of risk for little overall gain.
For an operation such as 121 turbine, where risks are kept to the absolute minimum (and understandably so), I'm surprised this would be a risk considered to be worth taking, by the airlines. If the RTO isn't near-perfectly accomplished or some other problem crops up during the initiation of it, that runway left behind would be highly desired at best, and critical life or death at worst.
Trusting data when the runway is indeed limited is one thing. Intentionally limiting available runway to where you've cornered yourself to the data with little to no slop available, just doesn't seem wise; barring extenuating circumstances.
jtrain609
Antisocial Monster
By using flex and derate numbers for takeoff you use more runway, but have a lower probability of the engine coming apart on you on takeoff because you're using such a low thrust rating.
As an example, in my aircraft this is so extreme that our climb power is almost always an INCREASE in N1 as compared to most takeoff thrust settings. As such we're more likely to have the engine to knock off for the day when we select that thrust setting, at around 2,000' AGL. I'd much rather have the risk of the engine failing occur at that point than at V1.
As such, I find that our data commonly has us rotating with about 3,000' left on almost any runway.
Does that mean you have a higher chance of rolling off the end of the runway at a few knots if you have to do an abort just before V1? Sure, but it also means you have a much lower chance of the engine coming apart on you to begin with, thus lowering the overall risk to the takeoff.
You've got to accept the risk somewhere, so this method just changed the place where that risk is assessed.
Which all makes sense, I agree, but still doesn't explain the concept of leaving unused runway behind you (and thus, potential stopway ahead of you) for nothing more than what would appear to be convenience, with anything but full length departures regardless of the numbers. That's a risk that seems to yield little tangible reward for an overall risk mitigating flight operation.
jtrain609
Antisocial Monster
I don't think I've ever done a takeoff in an airliner from an intersection that cut off more than 500' on a 10,000' runway. We simply don't plan to takeoff from halfway down the runway, even if we could in theory do so using no flex non-derate data.
BlueMoon
Well-Known Member
Only a few places come to mind that do it regularly are ORD (32L at T10 or 28R at N5) and JFK (31L at KK).
Also, you can only derate and flex so much. So the thrust numbers may not even be different and the RATOW may not even change from the full length vs an intersection T/O for an intersection, provided the runway is long enough.
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B767
Well-Known Member
Just because I'm uber bored today (football is almost on!)....
It's 33 at T10 in ORD.
JeppUpdater
Well-Known Member
At C5 we would always get takeoff data for G at EWR (dead center of 11000' 4L/22R) so we could depart anywhere up to midfield...really helped skip the conga line sometimes.
Unique situation and airplane though.
I can see skipping having to be stuck in the elephant crawl delays and things like that. It would just suck to need some runway on an RTO and not have it on the departure end because you left some of it behind you unused. Even if the numbers check. Again, we're talking within reason, and assuming that we aren't talking departing somewhere like VBG where you can leave a few thousand behind you, and still have 11,000+ in front of you to work with.
If the takeoff numbers check, the numbers check, and things are safe/legal. I fully agree. That's not in question. To me it's only a question of having a nice "pad" to the numbers thats there and costs nothing, but not taking advantage of it, when possible. That's all. YMMV.
If the takeoff numbers check, the numbers check, and things are safe/legal. I fully agree. That's not in question. To me it's only a question of having a nice "pad" to the numbers thats there and costs nothing, but not taking advantage of it, when possible. That's all. YMMV.