American 767 RTO at ORD
- Thread starter Colin Levy
- Start date
WestIndian425
Well-Known Member
I see your point, Mike. I think, for the most part, 121 operators are ultra conservative with the numbers. Generally, it's rare to see intersection takeoffs with more than 500' of usable runway lost unless that runway is at least 10,000' long.
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bLizZuE
Calling for engine starts en français
The numbers are already padded and ORD operations aren't conducive to always get a full length departure either.
Also, this runway is 13,000 feet long and the intersection still leaves about 10,000 feet.
Nark
Macho Superpilot
These old sage CFI's never flew transport category, part 25 certified aircraft either...
Nark
Macho Superpilot
§25.113 Takeoff distance and takeoff run.
(a) Takeoff distance on a dry runway is the greater of—
(1) The horizontal distance along the takeoff path from the start of the takeoff to the point at which the airplane is 35 feet above the takeoff surface, determined under §25.111 for a dry runway; or
(2) 115 percent of the horizontal distance along the takeoff path, with all engines operating, from the start of the takeoff to the point at which the airplane is 35 feet above the takeoff surface, as determined by a procedure consistent with §25.111.
(b) Takeoff distance on a wet runway is the greater of—
(1) The takeoff distance on a dry runway determined in accordance with paragraph (a) of this section; or
(2) The horizontal distance along the takeoff path from the start of the takeoff to the point at which the airplane is 15 feet above the takeoff surface, achieved in a manner consistent with the achievement of V2 before reaching 35 feet above the takeoff surface, determined under §25.111 for a wet runway.
(c) If the takeoff distance does not include a clearway, the takeoff run is equal to the takeoff distance. If the takeoff distance includes a clearway—
(1) The takeoff run on a dry runway is the greater of—
(i) The horizontal distance along the takeoff path from the start of the takeoff to a point equidistant between the point at which VLOF is reached and the point at which the airplane is 35 feet above the takeoff surface, as determined under §25.111 for a dry runway; or
(ii) 115 percent of the horizontal distance along the takeoff path, with all engines operating, from the start of the takeoff to a point equidistant between the point at which VLOF is reached and the point at which the airplane is 35 feet above the takeoff surface, determined by a procedure consistent with §25.111.
(2) The takeoff run on a wet runway is the greater of—
(i) The horizontal distance along the takeoff path from the start of the takeoff to the point at which the airplane is 15 feet above the takeoff surface, achieved in a manner consistent with the achievement of V2 before reaching 35 feet above the takeoff surface, as determined under §25.111 for a wet runway; or
(ii) 115 percent of the horizontal distance along the takeoff path, with all engines operating, from the start of the takeoff to a point equidistant between the point at which VLOF is reached and the point at which the airplane is 35 feet above the takeoff surface, determined by a procedure consistent with §25.111.
(a) Takeoff distance on a dry runway is the greater of—
(1) The horizontal distance along the takeoff path from the start of the takeoff to the point at which the airplane is 35 feet above the takeoff surface, determined under §25.111 for a dry runway; or
(2) 115 percent of the horizontal distance along the takeoff path, with all engines operating, from the start of the takeoff to the point at which the airplane is 35 feet above the takeoff surface, as determined by a procedure consistent with §25.111.
(b) Takeoff distance on a wet runway is the greater of—
(1) The takeoff distance on a dry runway determined in accordance with paragraph (a) of this section; or
(2) The horizontal distance along the takeoff path from the start of the takeoff to the point at which the airplane is 15 feet above the takeoff surface, achieved in a manner consistent with the achievement of V2 before reaching 35 feet above the takeoff surface, determined under §25.111 for a wet runway.
(c) If the takeoff distance does not include a clearway, the takeoff run is equal to the takeoff distance. If the takeoff distance includes a clearway—
(1) The takeoff run on a dry runway is the greater of—
(i) The horizontal distance along the takeoff path from the start of the takeoff to a point equidistant between the point at which VLOF is reached and the point at which the airplane is 35 feet above the takeoff surface, as determined under §25.111 for a dry runway; or
(ii) 115 percent of the horizontal distance along the takeoff path, with all engines operating, from the start of the takeoff to a point equidistant between the point at which VLOF is reached and the point at which the airplane is 35 feet above the takeoff surface, determined by a procedure consistent with §25.111.
(2) The takeoff run on a wet runway is the greater of—
(i) The horizontal distance along the takeoff path from the start of the takeoff to the point at which the airplane is 15 feet above the takeoff surface, achieved in a manner consistent with the achievement of V2 before reaching 35 feet above the takeoff surface, as determined under §25.111 for a wet runway; or
(ii) 115 percent of the horizontal distance along the takeoff path, with all engines operating, from the start of the takeoff to a point equidistant between the point at which VLOF is reached and the point at which the airplane is 35 feet above the takeoff surface, determined by a procedure consistent with §25.111.
That's what I was saying before. Its one thing to rely on the small pad given in being at or near the exact numbers, when there's no overriding need to be. It's another thing to lose a few thousand feet of runway, when there's still a very large pad of runway available.
Which is certainly legal. No issue. Just hope there isnt a situation where you wish you had that runway, because that would really suck
An RTO past V1 with an emergency that you know will be fatal if you liftoff and/or attempt to take it into the air.
There were a couple of those in my old jet. Ones where you aborted no matter what. Else wise you will end up a smoking hole in the ground somewhere off the departure end. Of course, we had the luxury of a drag chute, arrestor hook, etc.
That's why i don't leave unused runway behind me for convenience, unless we're talking still having lots of excess ahead still.
That's no criticism of what you're saying, it's just not risk i generally take for no major operational need. Both are fully legal and fine.
bLizZuE
Calling for engine starts en français
First, I respect you and your opinion immensely.
But there is no such thing as an RTO past V1. I'm certain you can point me to certain incidents that occurred beyond V1 that didn't go well but what you're talking about is second guessing the data after the point of no return.
Our briefs incorporate an "aircraft un-airworthy" situation but that's only after 80kts and prior to V1. After V1 we take the emergency airborne and deal with it because we can't risk the alternative. In my opinion we're attempting to fly an aircraft disabled versus nearly guaranteeing a runway/clearway excursion.
I would argue that even this AA RTO, had it occurred after V1, could have safely returned to the field. Stationary fire versus 150kts through the core and some halon would still have a more than excellent chance at the same outcome. However, if after V1 this crew decided to abort, now we're almost certain of a runway exit and who knows what else.
There may not be the idea of an abort past V1, but there are situations that will kill you if taken airborne. Air France Comcorde attests to that, even AA could've ended up like them, if the damage and fuel leaking were in an area of ignition that couldn't be controlled. Look at the Air France fire. Is that something that can really be planned for? Not really, because the crew wouldnt have known the damage extent just like the Air France crew didnt know their damage extent. Which is why the risk is taken of going past V1, vice an abort above that. Had they known the damage, I do wonder if they would've realized they don't have a flyable aircraft that would've survived a pattern circuit.
I had an abort about 15 knots above V1 once for a dual gen failure in a takeoff into IMC. That's one of the "you will die if you go airborne" emergencies in that jet. But again, I had a drag chute and arresting gear, which isn't figured into takeoff numbers as they're a luxury. Now that was a particular EP for that aircraft, but i tend to be really weary about things like bleed air leaks, cabin fire indication, on certain aircraft (obviously doesn't apply to all).
There are emergencies that would be far better keeping on the ground and risking damage/injury/death, rather than taking them into the air and guaranteeing those previous three end states. This isn't something really taught in the civil world, namely due to being a very rare occurrence. So the idea is taught that there is no abort above V1. Which in most cases is true.
Just some food for thought.
Cptnchia
Dissatisfied Customer
There's also a huge difference between military aircraft redundancy/airworthiness and a Part 25 certificated air transport aircraft.
The engines on a Boeing are designed to burn off the aircraft. On the Concorde they weren't. Different design, different outcome.
etflies
Keeping calm, Chiving on.
To be fair I don't think Concorde's crew knew the extent of the damage at the time. Simply that an engine went bang and there was a fire. I'd wager most airline pilots would've gone flying in that scenario given the same information.
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That's what I'm saying, it varies by aircraft. Although things like a cabin/fuselage fire would still have a very good chance of ending up terminal into a smoking hole. There are times you don't want to take a sick/dying aircraft airborne; although the ability to realize that in the few seconds there is when something occurs at/around/above V1, might not be enough time.
That's what I was also saying, in the bolded portion above your reply. They didn't have any idea of the extent of the damage they had, or the fire they had; which is why I said "if it's even realized'. I do wonder if, had they known somehow the extent, if that may have changed the reaction. We'll never know.
Then again, in the CV-990 NASA accident at RIV, they had the benefit of video cameras looking at the main landing gear, which helped them actually see what was going on with the blown tires and bogie fire, and that one still ended up in a destroyed aircraft, albeit with no injuries.
Hence, why this is a food for thought. There's nothing wrong with the current ideology, as the risk is generally low of occurence. But I'd still not want to leave significant runway behind me, solely for convenience. If there's an operational necessity and the numbers check, I'd think about it, but for me that's the exception rather than the norm. Again, both ways perfectly legal, no issues there.
No worries brother. You reiterate a point that is very valid. The chances of realizing the extent of a problem in the short few seconds available to do so, may be very difficult.
Cherokee_Cruiser
Bronteroc
Meh, I can think of cases where I wouldn't bother.
BOS runway 27 which is 7,000 feet going to SFO and/or LAX on an A320. I've gotten legal numbers before which included a TOGA takeoff, flaps 3, and APU bleed on. Stopping distance remaining (assumes going to V1 and rejecting) was 200 feet.
No thanks!
We're getting 15R/33L.