Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]
Groups > aus.aviation > #27488
| From | "Rod Speed" <rod.speed.aaa@gmail.com> |
|---|---|
| Newsgroups | aus.aviation |
| Subject | Re: Dash-8 incorrect takeoff configuration. |
| Date | 2025-01-26 10:07 +1100 |
| Message-ID | <op.20yc6azibyq249@pvr2.lan> (permalink) |
| References | (7 earlier) <lvihukFd5foU1@mid.individual.net> <lvjmkaFiof3U1@mid.individual.net> <lvk0m9Fk87oU1@mid.individual.net> <lvk9r1FllumU1@mid.individual.net> <lvl7bkFq9oqU1@mid.individual.net> |
On Sun, 26 Jan 2025 09:36:36 +1100, Daryl <dwalford@westpine.com.au> wrote: > On 26/1/2025 1:12 am, Sylvia Else wrote: >> On 25-Jan-25 7:36 pm, Daryl wrote: >>> On 25/1/2025 7:44 pm, Sylvia Else wrote: >>>> On 25-Jan-25 6:19 am, Daryl wrote: >>>>> On 25/1/2025 12:59 am, Sylvia Else wrote: >>>>>> On 24-Jan-25 4:21 pm, Rod Speed wrote: >>>>>>> Sylvia Else <sylvia@email.invalid> wrote >>>>>>>> Rod Speed wrote >>>>>>>>> Sylvia Else <sylvia@email.invalid> wrote >>>>>>>>>> Rod Speed wrote >>>>>>>>>>> Sylvia Else <sylvia@email.invalid> wrote >>>>>>> >>>>>>>>>>>> https://www.atsb.gov.au/publications/ >>>>>>>>>>>> investigation_reports/2025/ report/ao-2024-038 >>>>>>> >>>>>>>>>>>> It's time all public transport aircraft had takeoff >>>>>>>>>>>> performance monitoring, no matter the size. >>>>>>> >>>>>>>>>>> That isnt going to result in the problem being >>>>>>>>>>> fixed quickly enough to stop an accident >>>>>>> >>>>>>>>>> Well before an abort becomes risky, the system has enough >>>>>>>>>> informationto determine whether the crew calculated v1 and vr >>>>>>>>>> are correct, >>>>>>> >>>>>>>>> Bullshit with that incorrect flaps setting. >>>>>>> >>>>>>>>>> and whether the aircraft will be able toboth continue a >>>>>>>>>> takeoff, and stop, at v1. >>>>>>> >>>>>>>>> Bullshit with that incorrect flaps setting, let alone >>>>>>>>> tell the pilots that the flaps setting is wrong. >>>>>>> >>>>>>>>> It would make much more sense to compare the >>>>>>>>> actual settings with that has been entered at the >>>>>>>>> preflight config calculations and tell the pilots >>>>>>>>> that they have not set what was required with >>>>>>>>> flaps and boost etc before they actually applied >>>>>>>>> takeoff power and not allow takeoff power to be >>>>>>>>> applied before those were set correctly. >>>>>>> >>>>>>>>>> It can issue an abort alert if not. >>>>>>> >>>>>>>>> See above >>>>>>> >>>>>>>>>> This covers at least miscalculated v1, miscalculated vr, wrong >>>>>>>>>> thrust settings, wrong flap settings, starting from the wrong >>>>>>>>>> intersection, takeoff from the wrong runway, and no doubt >>>>>>>>>> others that I haven't even thought of. >>>>>>> >>>>>>>>> It would be stupid to try to measure that while taking off >>>>>>>>> instead of doing that before takeoff power is applied >>>>>>> >>>>>>>>> Yes, there is also a different problem with the engines >>>>>>>>> not being able to deliver the power they were assumed >>>>>>>>> to be able to deliver the power they were supposed to >>>>>>>>> be able to deliver in the preflight calculations, but that >>>>>>>>> was not the case in the incident being discussed and >>>>>>>>> it would be much easier to discover than much earlier >>>>>>>>> in the takeoff run than V1 or VR >>>>>>> >>>>>>>> The question the system needs to ask is "In the current >>>>>>>> configuration, with the measured acceleration [*], current >>>>>>>> airspeed, and current position on the current runway, can the >>>>>>>> aircraft reach the specified V1 at a point where it can continue >>>>>>>> the takeoff or abort, and will it be able to rotate at the >>>>>>>> specified Vr. >>>>>>> >>>>>>> The problem with that approach is that is far too late >>>>>>> during the takeoff run to be doing that by measurement >>>>>>> when its much too late for the pilots to be fixing what >>>>>>> the problem is, particularly when the engines arent >>>>>>> actually performing the way they were meant to when >>>>>>> the prefight calculations were done >>>>>> >>>>>> There would be no expectation that the pilots would fix it. The >>>>>> idea is to abort the takeoff while that can still be done safely. >>>>> >>>>> I assume that you are talking about some sort of automated system to >>>>> alert pilots of a configuration error? >>>>> If so wouldn't that rely on data input by the pilots prior to >>>>> takeoff so the system would be only as good as the data therefore it >>>>> doesn't completely eliminate the chances of an error? >>>>> In this incident did the pilots self report? >>>>> If they didn't why would the ATSB investigate? >>>>> >>>>> >>>>> >>>>> >>>> >>>> My thinking is that the system has access to the settings for flap, >>>> thrust, mass, V1 and Vr. None of these is assumed to be correct. >>>> >>>> Also access to GPS and airspeed. >>>> >>>> In the following, the system would allow some level of discrepancy so >>>> as not to cause unnecessary aborts. >>>> >>>> Once the aircraft is accelerating, its direction together with the >>>> GPS calculated position allows the system to determine which runway >>>> the aircraft is on (position alone may not be sufficient, where >>>> runways intersect). >>>> >>>> The acceleration to be expected from a given thrust setting depends >>>> on the aircraft's mass, and its airspeed. So the system waits until >>>> there is a reliable airspeed. It then can calculate the mass from the >>>> expected thrust, the acceleration and the airspeed. The result should >>>> match the setting. If it doesn't this means that either the mass is >>>> set wrong, or the expected thrust, based on the thrust setting, is >>>> not being achieved. Either of these aborts the takeoff. >>>> >>>> Vr can now be calculated based the mass and flap setting. If the >>>> calculated Vr differs from the set Vr, this aborts the takeoff. >>>> >>>> From the current position, the acceleration and the mass, the >>>> braking distance can be calculated [*], and from that V1. If the >>>> calculated V1 is lower than the set V1, then abort take off. >>>> >>>> [*] This is one area of uncertainty, since braking distance depends >>>> on runway condition (wet, dry, etc.). >>>> >>>> Sylvia. >>>> >>>> >>> My piloting experience is 5hrs training in a helicopter so not much >>> but to me it sounds a bit complex and still open to input error to be >>> of much value? >>> Might be feasible on newer complex aircraft but retrofitting such a >>> system on older aircraft would most likely be very expensive and maybe >>> not even possible. >>> You didn't answer the question about self reporting, was that >>> mentioned in the ATSB report? >>> >>> >> I can't find a specific reference to how this came to the attention of >> the ATSB. Most likely it was reported to Qantas Link by the pilots, and >> Qantas Link then reported it to the ATSB. > Would it be mandatory for the pilots to report to the airline or just > good practice? Its manditory > If the airlines culture encouraged them to report without consequence > then its a good safety measure, maybe that's why airlines in Australia > have such a good safety record? Its not just manditory here, that is true right thruout the entire industry world wide, but not followed in the 3rd world necessarily
Back to aus.aviation | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread
Dash-8 incorrect takeoff configuration. Sylvia Else <sylvia@email.invalid> - 2025-01-21 13:28 +0800
Re: Dash-8 incorrect takeoff configuration. "Rod Speed" <rod.speed.aaa@gmail.com> - 2025-01-23 04:21 +1100
Re: Dash-8 incorrect takeoff configuration. Sylvia Else <sylvia@email.invalid> - 2025-01-23 12:50 +0800
Re: Dash-8 incorrect takeoff configuration. "Rod Speed" <rod.speed.aaa@gmail.com> - 2025-01-23 20:09 +1100
Re: Dash-8 incorrect takeoff configuration. Sylvia Else <sylvia@email.invalid> - 2025-01-24 14:14 +0800
Re: Dash-8 incorrect takeoff configuration. "Rod Speed" <rod.speed.aaa@gmail.com> - 2025-01-24 19:21 +1100
Re: Dash-8 incorrect takeoff configuration. Sylvia Else <sylvia@email.invalid> - 2025-01-24 21:59 +0800
Re: Dash-8 incorrect takeoff configuration. "Rod Speed" <rod.speed.aaa@gmail.com> - 2025-01-25 03:46 +1100
Re: Dash-8 incorrect takeoff configuration. Daryl <dwalford@westpine.com.au> - 2025-01-25 09:19 +1100
Re: Dash-8 incorrect takeoff configuration. Sylvia Else <sylvia@email.invalid> - 2025-01-25 13:17 +0800
Re: Dash-8 incorrect takeoff configuration. "Rod Speed" <rod.speed.aaa@gmail.com> - 2025-01-25 19:34 +1100
Re: Dash-8 incorrect takeoff configuration. Sylvia Else <sylvia@email.invalid> - 2025-01-25 16:44 +0800
Re: Dash-8 incorrect takeoff configuration. Daryl <dwalford@westpine.com.au> - 2025-01-25 22:36 +1100
Re: Dash-8 incorrect takeoff configuration. Sylvia Else <sylvia@email.invalid> - 2025-01-25 22:12 +0800
Re: Dash-8 incorrect takeoff configuration. Daryl <dwalford@westpine.com.au> - 2025-01-26 09:36 +1100
Re: Dash-8 incorrect takeoff configuration. "Rod Speed" <rod.speed.aaa@gmail.com> - 2025-01-26 10:07 +1100
Re: Dash-8 incorrect takeoff configuration. "Rod Speed" <rod.speed.aaa@gmail.com> - 2025-01-26 02:21 +1100
Re: Dash-8 incorrect takeoff configuration. Sylvia Else <sylvia@email.invalid> - 2025-01-26 16:29 +0800
Re: Dash-8 incorrect takeoff configuration. "Rod Speed" <rod.speed.aaa@gmail.com> - 2025-01-26 20:14 +1100
Re: Dash-8 incorrect takeoff configuration. Sylvia Else <sylvia@email.invalid> - 2025-01-27 12:17 +0800
Re: Dash-8 incorrect takeoff configuration. "Rod Speed" <rod.speed.aaa@gmail.com> - 2025-01-27 19:52 +1100
Re: Dash-8 incorrect takeoff configuration. Sylvia Else <sylvia@email.invalid> - 2025-01-27 16:56 +0800
Re: Dash-8 incorrect takeoff configuration. "Rod Speed" <rod.speed.aaa@gmail.com> - 2025-01-28 04:33 +1100
Re: Dash-8 incorrect takeoff configuration. Sylvia Else <sylvia@email.invalid> - 2025-01-28 11:52 +0800
Re: Dash-8 incorrect takeoff configuration. "Rod Speed" <rod.speed.aaa@gmail.com> - 2025-01-28 15:57 +1100
csiph-web