Departing Saudia Cargo 747 'departs' runway
SkyGod
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I had the nosewheel on the 747-100/200 slide sideways across dry pavement many times, a lot less than 5-12 tons weight on it. Try 500 kilos if empty.
(Yes, we used center tank ballast fuel when flying empty but the nose still seemed very light, steering was best done with brakes and power.)
(Yes, we used center tank ballast fuel when flying empty but the nose still seemed very light, steering was best done with brakes and power.)
Lots of current cars have stability control systems that automatically apply differential braking to prevent excessive "yaw." It doesn't seem like it would be technically difficult to install a version of that on an aircraft, perhaps set to be active only if there's an uncommanded thrust reduction on an outboard engine below 80 knots (or something like that). But I guess it's late in the 747 lifecycle.
74 engines produce in excess of 60,000lbs of thrust each.
That can not be corrected with differential braking.
Folks,
Various comments about the nose gear.
Believe me, in the situation under discussion, the ONLY contribution of the nose gear is to keep the nose off the ground. Nose gear steering is not going to contribute anything of significance to staying on the runway.
Indeed, depending on the weight and CofG, just doing a turn on a surface of normal friction, dead slow speed, can get interesting, with the usual muck and a bit of rain, work it out for yourself.
Use of differential brake, and a bit of thrust on the outboard, read Boeing's "recommendations" carefully, all is permitted that is not specifically prohibited.
Bottom line, "in the event", how fast you get the thrust levers hard back on the stops will determine the tenor of the discussion, when you next have a chat with the CP.
Various comments about the nose gear.
Believe me, in the situation under discussion, the ONLY contribution of the nose gear is to keep the nose off the ground. Nose gear steering is not going to contribute anything of significance to staying on the runway.
Indeed, depending on the weight and CofG, just doing a turn on a surface of normal friction, dead slow speed, can get interesting, with the usual muck and a bit of rain, work it out for yourself.
Use of differential brake, and a bit of thrust on the outboard, read Boeing's "recommendations" carefully, all is permitted that is not specifically prohibited.
Bottom line, "in the event", how fast you get the thrust levers hard back on the stops will determine the tenor of the discussion, when you next have a chat with the CP.
Last edited by LeadSled; 14th Nov 2017 at 11:04.
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I’m sorry, but there is so much rubbish being spoken here. Yes the classic B747 does have similarities to the B744, they both have a hump! But it’s the automatics the auto throttle system which needs to be understood.
Forget all the rubbish about nose wheel steering etc. Ignore the slippery runway, it was damp, possibly wet.
I have around 15000 hours on the B747, most of it as a skipper on the B744.
Yes this is a ‘rumour’ network, but come on. This is why Pprune is akin to the U.K. Daily Mail.
A low speed reject in a B744 is tricky, but we train for it.....every 6 months. If you can’t do it....don’t fly it.
But at the end of the day SOPs cover it, don’t have a go at Boeing, don’t insinuate design flaws. Don’t compare it to other aircraft, when you obviously don’t understand the systems. It’s nothing like the ‘classic’, I know I flew the classic for five years......twenty more on the 400 variant.
FACT 90 degrees off centreline at low speed, in the grass, is gross pilot error. Regardless of any report. Here ends the lesson.
Forget all the rubbish about nose wheel steering etc. Ignore the slippery runway, it was damp, possibly wet.
I have around 15000 hours on the B747, most of it as a skipper on the B744.
Yes this is a ‘rumour’ network, but come on. This is why Pprune is akin to the U.K. Daily Mail.
A low speed reject in a B744 is tricky, but we train for it.....every 6 months. If you can’t do it....don’t fly it.
But at the end of the day SOPs cover it, don’t have a go at Boeing, don’t insinuate design flaws. Don’t compare it to other aircraft, when you obviously don’t understand the systems. It’s nothing like the ‘classic’, I know I flew the classic for five years......twenty more on the 400 variant.
FACT 90 degrees off centreline at low speed, in the grass, is gross pilot error. Regardless of any report. Here ends the lesson.
fabvirgil,
You are not the only one posting here with a long and intimate acquaintance with the B747, all models. I don't really believe anybody was suggesting that Boeing got it wrong, just stating a few facts of life. There is nothing in any of my comments that is inconsistent with the AFM for any model.
Did you ever have a low speed abort with the thrust set?? In the real world, as opposed to the simulator?
Indeed, differing only in degree, the same thing could be said about any of the four-engine jets. One night in Tokyo, many years ago, I saw the results of a mishandled abort in a DC-8 --- the aircraft was a write-off.
Perhaps, despite your experience, reading the FAA study on real world aborts, or the Boeing studies on same, would be of real value.
You are not the only one posting here with a long and intimate acquaintance with the B747, all models. I don't really believe anybody was suggesting that Boeing got it wrong, just stating a few facts of life. There is nothing in any of my comments that is inconsistent with the AFM for any model.
Did you ever have a low speed abort with the thrust set?? In the real world, as opposed to the simulator?
Indeed, differing only in degree, the same thing could be said about any of the four-engine jets. One night in Tokyo, many years ago, I saw the results of a mishandled abort in a DC-8 --- the aircraft was a write-off.
Perhaps, despite your experience, reading the FAA study on real world aborts, or the Boeing studies on same, would be of real value.
I experienced an outer engine failure on a TOGA A340 departure at about 60 kts. It did indeed require differential braking to counter the very rapid and large swing away from the centreline of the runway. In my experience this scenario is not nearly carried out often enough in the sim.
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I've been flying the 747-200/400/-8 for a legacy airline for two decades and I've NEVER practiced the above scenario in the sim.
I'll be asking to give it a go next time though...
I'll be asking to give it a go next time though...
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I am surprised and you work for a legacy carrier in Hong Kong? For your next recurrent training, try a -400/-800 eng 1 or 4 low speed abort on a contaminated runway. Fun stuff...in the sim.
Nemo Me Impune Lacessit
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Start Fore - Do you operate Cat2/3? If you do, once you have done a few 'ordinary' rejects get the SIM instructor to give you the failure using Reduced Visibility procedures so that you are monitoring the black and white 'barbers pole' on the coaming, it can become even more interesting!
Start Fore,
What you say does surprise me, because Boeing training material on the subject is quite extensive.
As parabellum quite rightly says, in 100M viz., it can get quite exciting.
In my company, which has also been around for quite a time, it makes regular random appearances in the cyclic training program.
Indeed, we always made the point that you don't get a "practice go" before an engine failure on takeoff on the line, so why should base or simulator training be any different.
I don't know what your company is like with "staff suggestions", but is does suggest a gap in the training that needs to be filled.
What you say does surprise me, because Boeing training material on the subject is quite extensive.
As parabellum quite rightly says, in 100M viz., it can get quite exciting.
In my company, which has also been around for quite a time, it makes regular random appearances in the cyclic training program.
Indeed, we always made the point that you don't get a "practice go" before an engine failure on takeoff on the line, so why should base or simulator training be any different.
I don't know what your company is like with "staff suggestions", but is does suggest a gap in the training that needs to be filled.
Whilst the low speed RTO with an outboard engine failure would arguably be one of the most difficult manoeuvres in the -400, the other being an outer engine failure on the upwind side in a strong crosswind just as the gear is lifting off, nevertheless as long as the appropriate thrust for the weight and not some macho thrust has been set, it is easily done (with correct training) at just 30 or 40 kts and in RVRs where you can only count a few centerline lights. There may be a bigger issue here I suspect. They were not very succesful at completing an ILS with a servicable aircraft at Bishkek in January.
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Not ever flown a 4-pot, is it more likely to have a bird strike in the outboard engines than the inners? If that is so, then surely practicing the more difficult and likely event is the proper use of simulators. Assuming you have performed the mandatory RTO training due to engine failure, that would suggest that many operators must choice the inboard engines. My question is why? Why not choose any engine and therefore cover all possibilities? Equally, why not train the difference a/c reaction to inboard/outboard engine failures and with left/right x-winds, and wet runways. There has to be a significant difference; having read the posts from the experienced crews. Surely the company has a strong interest in training its crews not to bend its high value assets when the poo hits the fan. Ticking boxes is not training. We've seen the consequence of that philosophy in real-life events.
Come on XAA's, review your remit over airline training.
Come on XAA's, review your remit over airline training.
Engine failure?
Only Saudi says so in the aftermath of the incident.
AvHerald
Only Saudi says so in the aftermath of the incident.
Saudia Cargo's parent Company Saudi Arabian Airlines reported the aircraft suffered an engine problem causing the runway excursion while attempting to takeoff. There were no injuries and no damage.
The Dutch DSB reported they opened an investigation into the runway excursion of a cargo aircraft at Maastricht Airport.
On Nov 16th 2017 the DSB reported that the aircraft of ACT Airlines was accelerating for takeoff when the aircraft suddenly pulled to the right, the crew could not correct, the aircraft exited the runway and came to a stop in the grass. The 4 crew remained uninjured, the aircraft sustained damage. The cargo and fuel were unloaded, then the aircraft was recovered and moved back onto paved surface. The investigation is ongoing with the assistance from Turkish, American and British accident investigation authorities.
The Dutch DSB reported they opened an investigation into the runway excursion of a cargo aircraft at Maastricht Airport.
On Nov 16th 2017 the DSB reported that the aircraft of ACT Airlines was accelerating for takeoff when the aircraft suddenly pulled to the right, the crew could not correct, the aircraft exited the runway and came to a stop in the grass. The 4 crew remained uninjured, the aircraft sustained damage. The cargo and fuel were unloaded, then the aircraft was recovered and moved back onto paved surface. The investigation is ongoing with the assistance from Turkish, American and British accident investigation authorities.
RAT 5: 4 engine check rides in the sim and on the aircraft (when we used to do it) always require the most limiting condition to be used ie. an outer engine.
The whole point of this thread is to highlight the condition where directional authority is poor prior to Vmcg and to point out how nasty a seemingly low speed event can be.
The whole point of this thread is to highlight the condition where directional authority is poor prior to Vmcg and to point out how nasty a seemingly low speed event can be.
Last edited by Meikleour; 16th Nov 2017 at 21:59. Reason: added para
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Engine failure?
Only Saudi says so in the aftermath of the incident.
Only Saudi says so in the aftermath of the incident.
No, it was reported as such on the r/t to ATC. I have no idea what the nationalities of the crew were (they are quite mixed at ACT) but quite likely not Saudi.
If it happened over 20 knots, then the body gear steering would not be operative on the 744. In slippery conditions, the nose-wheel does very little to help you steer.