Rejecting A Takeoff After V1…why Does It (still) Happen?

[galaxy flyer]

With 11,000 hours in fighters, biz jets, heavy transports, civil and military, I'll stack my experience and training against yours, any day.

None of us has said that we are automatons that ONLY consider what the ASI says, we do think, but we also learn from the totality of aviation. We have learned that continuing is more likely than not to be a better choice. When the wings come off after hitting your fictional fuel truck, I'll stop, regardless of the speed. And I'll teach others to do so.

Enough with your straw man arguments that bear NO resemblance of reality. Performance calculations, not a guess out the window, guide the pros.

GF

[johns7022]

I doubt your concession NOW to the possibilities that I presented, that would most certainly guaranty your killing a plane load of people by continuing on...will NOW translate into a post V1 RTO in your future....you've taken an entrenched position that post V1 RTOs are BAD, horrible and ugly.

You can't argue against it for a day, then say...'well ok, I would do it, I guess, the but odds are I won't make it, I guess, but gee whiz, it's not a good idea...because too many other guys rolled into the grass...so I guess I might too....so uh, well, I'm not a robot, so uh..well..gee...I would probably just go...maybe'

For me this isn't rocket science...I hear a bang, I haven't rotated yet, I see 5000 ft (or much less)of runway ahead, I stop...big deal.

[Sciolistes]

For me this isn't rocket science...I hear a bang, I haven't rotated yet, I see 5000 ft (or much less)of runway ahead, I stop...big deal.

The salient points are, unlike just about any other manouevre, that there is very little margin for error with and RTO. Any delay or mistake will likely end in an overrun. If you have time to think between V1 and Vr then you probably don't have enough runway. So it isn't rocket science, unless you are absolutely certain that the aircraft won't fly, the lesser risk is to accept an overrun and the relatively small number of deaths and serious injuries that result. It is a stark choice!

[johns7022]

It's a fallacy that an RTO is a danger fraught maneuver.....pull the levers back, pop the TRs, add brakes...

An RTO is dangerous if you purposefully reduced thrust and stretched your balanced field into the weeds to keep those 25000 hour engines running another 10,000 hours........

[BOAC]

Originally Posted by johns7022

can take the wings off a 737 and go up and down the runway accelerating to V1 all day long

- I fear this poster may be shooting from elsewhere? Thinks - I wonder if he/she has any idea where the engines are on a 737? Bag of marbles in the Christmas stocking perhaps?

[Sciolistes]

I am with you on the airmanship thing and not blindly following procedures without any understanding of what is going on. But according to my training, an RTO near V1 is a risky manouevre. The FCTM backs this up as does the theory that I was taught during my ATPL ground school. I would honestly be interested to study any other references you can provide.

As a pilot, my assumption is that an RTO initiated after V1 will result in an overrun.

[galaxy flyer]

John7022

I have no doubt, in the Global on 10,000 feet of runway, I hear a "bang" at V1, I'd stop, too. Just as, if a fuel truck leaps out in front of me and takes the wing off, I'll stop-- no choices there. But the real conversation is on the ASDR-limited (field length limited) and an engine rolls back or you get a simple fire light, then what? Take an overrun when the basic airworthiness is not in question. The plane and passengers are safer airborne and landing out of a controlled approach. Had the EMAS not been place at KCRW, the CRJ would have gone over the edge with loss of life. That is the real life story, not your silly extreme straw man arguments.

GF

[Non-PC Plod]

I come from the rotary-wing world, and I thought we were light years behind you fixed wing fellas in terms of MCC procedures, but I'm quite surprised that no-one on this thread has mentioned either a departure brief or SOPs.
SOPs help to save us from making rash decisions in the heat of the moment.Thats why we normally follow them.
If we are in a situation where there is a better solution than to go with the SOP - for example a 5 mile long runway, do you not brief it as a crew in advance, rather than just cuffing it?
eg:
"Today, we have a 5 mile long runway, so in the event of an engine malfunction after V1, I will delay the go/nogo decision until.........."

[PEI_3721]

Approaching the decision point.

Discuss further issues of rejected takeoffs, human error, misguided thinking, or poor attitude, where the latter does little to promote professionalism in our industry.

No; reject, add to ignore list. Choose a safer option, less risk of high blood pressure, head banged against the wall, or frustration of declining standards in our industry.

P.S. on reflection, if some of the more extreme discussion, as above, involves ‘real’ professional pilots, then there is an urgent need for education, which the thread initiating post, report, and FAA training aid seeks to implement.

[GlueBall]

johns7022 . . .

"I see 5000 ft (or much less)of runway ahead, I stop...big deal."

...just because you still see lots of pavement ahead does not ensure that you will stop before it ends, because when your brake energy has been dissipated you can stand on the pedals and you will continue rolling with zero brakes.

Typically there's an average of a ten knot spread between V1 and VR . . .and you're telling us that in that 2 second interval you could decide that the airplane would not be able to fly . . . ?

A nut case B747 captain with your mentality at Bruxelles had heard a bang [compressor stall] after V1 and had imagined that the airplane would not fly, then he had aborted more than 10 knots past V1. . . destroyed the airframe and had narrowly averted the deep end drop unto the rail tracks and high tension wires.

[johns7022]

Ah yes the failing brake argument....that brakes are perfectly reliable for landings, but during RTOs your brake disks turn into marshmellows...but not on landings...only RTOs.

[galaxy flyer]

The energy absorption in a RTO is, at least, twice that of a normal landing in a B747 class plane. RTOW for a long-range plane will be on the order of 75% greater than landing weight, the Vref will be, on the order of, 25-35 knots less than Vr. The energy absorption is huge, on the order of 33 million ft/lbs per brake. I don't know the specifics on the 744, but on the C-5 taxi-out will raise the brakes by 100-150C, depending on turns, weight and length of taxi. A heavy jet transport is streets away from your Citation. A RTO at heavy weights will raise the temps to the fuse plug blow-out temps.

You continue to express opinions on subjects you have no training and no relevant experience and tell those with the training and experience that they are wrong, or worse, dangerous. Please spend time learning about FAR 121 operations and the relevant certification background. Reduced power take-offs and "on condition" maintenance appear to be special bugaboos, both common procedures, even on several FAR 25 certified business jets and regional jets using the same engines.

Airlines are not the safest form on transportation because they do stupid things, have incompetents at the helms.

GF

[johns7022]

Yeah...I am sure that the FAA certifies jets so that they can brake effectively at gross, from V1, all day long, year after year, but if you go over 5-10 kts...everyone is a goner....

I think Boeing is putting you guys on...for some reason they would rather have you guys fight the fire around the pattern then pull the levers back and stand on the pedals..

It would be curious to know the real reason why...

[Old Fella]

RTOW as much as 75% greater than Landing Weight.

Dont think so. Example MTOW for a B747-200 is around 370,000 Kgs. MLW is around 285,000 kgs. I think you meant RTOW can be around 25% greater than MLW.

[SNS3Guppy]

Yeah...I am sure that the FAA certifies jets so that they can brake effectively at gross, from V1, all day long, year after year, but if you go over 5-10 kts...everyone is a goner....

What exactly is your point, here?

Brake effectively at gross what? Are you saying that a fully loaded airplane can do maximum braking "all day long?" If so, you're absolutely clueless on the subject. Particularly with respect to a rejected takeoff.

This subject has been discussed at great length, and use of the search engine may educate you more than attemtping to set straight your misguided ideas. If you can take the approach you do, you can only do it from a standpoint of utter ignorance of the dynamics involved in a rejected takeoff, as well as complete ignorance of takeoff dynamics and performance calculation.

The braking effectiveness isn't the issue with respect to rejecting a takeoff after V1. Having insufficient runway is certainly an issue.

Boeing is shining everyone on, you say? Shining everyone on with accurate, proven data? Shining everyone on by performing to Part 25 certification standards? Shining everyone on by enabling crews to calculate the performance for their takeoff on a given day, with a given payload, a given fuel load, a given set of ambient, environmental conditions? Really?

When we calculate our takeoff data, we do so given real world conditions, and real world aircraft performance. We know what the aircraft can, and can't do. What it can do is perform a rejected takeoff, at the hands of the crew, prior to V1. What it cannot do is safely allow the crew to perform a rejected takeoff after V1. Insufficient runway remains.

Apparently you don't understand this.

We have a major advantage continuing and coming back to land, rather than rejecting. When rejecting, all the runway is behind us. When coming back to land, it's all out in front. In case you weren't aware, that's a good thing.

[Spendid Cruiser]

The captain called “reject” 1.3 sec after the loss of power and initiated the associated action 0.8 sec later by retarding the power levers to idle as the aircraft was accelerating through 172 kt 7,300 ft along the runway. The flight engineer, noting that lights indicating that the thrust reversers were deploying had not come on, called "No reverse" and immediately moved the spoiler handle back. As a result, the spoilers were deployed and the autobrake system activated. At this point, the aircraft had accelerated to 175 kt and was 7,850 ft down of the runway, and 3,150 ft from the end.
Reverse thrust power was applied as the aircraft was decelerating through 140 kt, 1,850 ft from the end of the runway.
The autobrake began applying pressure 1.8 sec after the captain pulled the power levers back to idle. This activation of the autobrake was the direct result of the flight engineer manually deploying the spoilers when he noted the thrust reversers had not been selected. The thrust reversers were not deployed until 3.5 sec after the power levers were retarded. The brake pedals were not used by the crew during the rejected takeoff.
Although the Abnormal Procedures checklist current at the time of the accident did not call for immediate manual activation of the spoilers, the flight engineer’s actions to do so, in accordance with airline standard operating procedures (SOPs), greatly reduced the amount of overrun. The engine maintenance records indicated that the three engines on the aircraft had been maintained in accordance with the manufacturer's recommendations;

[homebuilt]

Ah yes the failing brake argument....that brakes are perfectly reliable for landings, but during RTOs your brake disks turn into marshmellows...but not on landings...only RTOs.

Somehow yes, because you have to take into account the huge difference between TOW (MTOW) and LW (MLW) on an heavy transport airplane. Speaking of the B744 for example you have a MTOW close to 400 metric tons (396800 kgs), vs a MLW of 285700 kgs (with actual LW around 250 - 260 metric tons in the average).

If you can compare the brake energy required to stop a close to 400-ton airplane starting at ~170 kts (~V1 at MTOW) - the case of the RTO -, and the brake energy required to stop the same airplane but at 260 tons, starting at ~145 kts (~Vref at that weight), with the cinetic energy formula 1/2 M V2, that gives you a balance of a little more than 2 against 1.

Roughly speaking, that means that on such an airplane, in order to be able to reject the take-off brakes must deliver a little bit more than twice the energy that they have to give for a max breaking landing (most times I perform landings using the autobrake set to 3 on a range that shows 1,2,3,4, MAX, and .... RTO).

That's all the difference and that's why a MTOW RTO at V1 is likely to finish in the grass with the landing gear burning...

But as I told earlier with the example of the MD83 colliding the Shorts 330, it's airmanship management and indeed sometimes you won't have any other choice but rejecting T/O whichever the speed... But in that case one has to be aware of the potential consequences.

[johns7022]

Put away the crash reports...more airliners FLY to the scene of the accident then roll to the incident on departure.

Besides...if you had to sit in the back...are you convinced the new FO is better prepared to pull the levers and add brakes...or hand fly a broken aircraft into the soup?

[homebuilt]

Besides...if you had to sit in the back...are you convinced the new FO is better prepared to pull the levers and add brakes...or hand fly a broken aircraft into the soup?

No way: in the airline I'm flying for SOPs stipulate that whichever the Pilot Flying is (Capt or FO), the RTO is carried out by the Capt, the FO handling the monitoring tasks and dealing with coms.

[Spendid Cruiser]

Put away the crash reports

And yet there you are arguing a case that has already resulted in an overrun.

...more airliners FLY to the scene of the accident then roll to the incident on departure.

Obviously, how is that relevant to the discussion?