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Four Donk Plane with two out

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Four Donk Plane with two out

Old 6th Jun 2008, 03:59
  #21 (permalink)  
 
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The DEFATO very manageable in a VC10. In the RAF, it was a simulator practice item every six months - probably still is. It takes a bit of skill and has a cleanup which involves bringing the flats and slats in independantly, but is deemed necesary because of the paired engine design. A catestrophic failure of one could take out the other.

It happened to BOAC/BA three times. The first to John Smurthwaite out of LHR. One of the engines detached and landed in a bunker on Ripley golf course. (Typical pilot - can't make the green in one!). The second to a Cap Robertson out of Calcutta after a multiple bird strike. The third to Roger Whitefield out of JKF in 1977 after a double engine fire indication. The UK Aircraft Accident Investigation Branch kept the CVR tape as an example of how to handle an emergency.
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Old 6th Jun 2008, 04:15
  #22 (permalink)  
 
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I would suggest that you read the report on the over-run of Bangkok by a Qantas B747-400 to see that it is not only F/E's who screw up.
You are mixing apples and oranges, Old Fella.
Qantas has very experienced and well trained crew, not just Captains.
However, some airlines are not so fortunate, and have rather junior folks assigned, and therefore rely on their very experienced expat Captains to handle adverse situations.
As one fleet manager told me, personally...'we know the limitations of our more junior guys, that's why you're here, and likely will remain, so long as you so choose.'
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Old 6th Jun 2008, 04:44
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411A

Slight thread drift here.

"........over-run of Bangkok by a Qantas B747-400.........."

I stand to be corrected here but was it not the misguided SOP, of said company, requiring reverse idle only, to be selected after touch down? This I believe was the one factor that made the difference been an overrun and staying on the runway. Saved fuel but cost them an a/c.
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Old 6th Jun 2008, 05:25
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Quote "I stand to be corrected here but was it not the misguided SOP, of said company, requiring reverse idle only, to be selected after touch down?"

Idle reverse is a SOP common to many 744 operators. It makes no difference to the landing distance and significantly saves on brake wear. In this accident, autobrake 4 had been selected but had automaticly deselected when the thrust levers had been advanced on the improperly actioned go around. After the decision to stay on the runway, the PF didn't select any reverse thrust.

There were many factors which caused this accident. The lack of reverse thrust was one, but more significant was the commander allowing the continuance of an unstabilised approach and his decision to stay on the runway after the aircraft touched down during the go around.

The full report can be read here: http://www.atsb.gov.au/publications/...904538_001.pdf
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Old 6th Jun 2008, 08:47
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Dan, your comment about splitting the flap/slats reminded me about practising DEFATO in the 70's with BOAC.

Haven't simulators moved on - the VC10 used to have a camera that moved over a wall of miniature trees and houses etc.

How often one did a low vis approach and, on breaking cloud at 300ft, found some wag had stuck a penthouse picture just before the runway threshold.

The only simulator I've flown where the footbrakes slowed the aircraft when airborne!!

I'll stop the memories now.
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Old 6th Jun 2008, 10:58
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The RAF VC10 sims had (have) computer generated images - and quite good ones too. You could fly formation on and refuel from other aircraft and watch aircaft refuel from you on the rearward facing CCTV.

I do remeber flying sims with camera over map type systems. Flying down a valley in Wales only to come accross a 300' high rubber spider is one memory!


And I take it back about pilots not being able to reach the green in one. The crew of Qantas 01 as mentioned seemed to have made it! (They ended up on the 18th on the glof course which is within the boundary of Bangkok Don Mueng airport for those who don't know).
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Old 6th Jun 2008, 11:15
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Apples and Oranges

411A, my reference to the QF B747-400 over-run at Bangkok was purely to illustrate that Captain's, as well as F/O's and F/E's are not infallible and that Captain's can, and do, make mistakes. If you care to read the report you will note that many factors contributed to the accident, including the actions of the Captain who made errors of judgement, failed to properly monitor the descent and approach, allowed the attempt to land to continue well past the point where a missed approach should have been carried out. failed to communicate his intentions, when cancelling an already initiated "go-around", to the F/O who was the handling pilot and failed to even consider the use of 30 Flap or Reverse thrust when landing on a rain soaked runway. A contributing factor was the QF preference of using only reverse idle and 25 Flap. Please read the report, in full, and forget the fallacious "Oranges and Apples" argument. By the way, I know Qantas has very high standards and an enviable safety record which they protect vigorously.
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Old 6th Jun 2008, 11:55
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Let's not forget of course the RAF Queens Flight BAe 146 which lost an engine shortly after takeoff (engine seized, or was into the red?), followed by another and then followed by another!

They landed with only one engine operating, and it had a limited time left as well....all the engine oil filler caps had been left off during overnight maintenance!
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Old 6th Jun 2008, 13:35
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I think it was the newly privatised maintenance facility which had forgotten to fit seals after a mag plug check. Still not sure doing all four in one go was a great plan....
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Old 6th Jun 2008, 18:49
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Disagree that reverse does not make a difference to landing distance.

That may be the case on a dry runway, using autobrakes for example on a wet runway the deceleration rate you expect may not be available due to less friction.

In this case reverse will 'help' you to obtain this rate.
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Old 7th Jun 2008, 03:04
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Effect of Reverse Thrust

Stilton is absolutely correct. In the case of the Qantas accident at Bangkok the use of FULL REVERSE in the prevailing conditions would have resulted in a reduction in landing distance of 422 metres, even with only 25 Flap. Had 30 Flap and FULL REVERSE been used the landing distance would have been reduced by 575 metres. As it was braking did not commence until 1625 metres past the threshold on a 3500 metre runway.
Threshold crossing speed was 168 KIAS (Vref + 19 knots) and threshold crossing height was 32 feet higher than planned. The increased speed and height over the threshold added 512 metres to the landing distance which would have been required otherwise. FULL REVERSE could have made the difference between remaining on the runway and exiting the end at 88 knots as happened. As Stilton correctly says, REVERSE does not have the same effect on a dry runway as on a wet or, in this case, a contaminated runway. Manufacturers do not go to the trouble and expense of fitting up Reverse Thrust systems for no reason.
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Old 7th Jun 2008, 04:19
  #32 (permalink)  
 
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I don't dispute that. I was commenting on the Qantas SOP of not using reverse thrust and that it's common in 744 operations. I doubt that their SOPs forbade the use. However, this crew believed they were doing the correct thing by briefing autobrake with reverse idle - their company's SOPs for the condition for which they believed the runway surface to be. But also, their SOPs were to land with F25 which I gather is a historic thing down to problems with the Classic's flaps.

My company's 744 SOPs were to use reverse if neccessary, but we didn't tend to - even on wet runways. In the wet case, we used a higher autobrake setting. The 744s autobrakes are very powerful, but unlike the Airbus', they don't give any indication of the level of decceleration. In this accident, the PF seems not to have noticed the lack of decceleration (the autobrake had actually disengaged). I don't remember a recall drill for loss of braking on the 744, the Airbus drill has you selecting full reverse almost immediately - which seems more than sensible.




Back to the original topic of the thread. In RAF service, the Victor was always flown assymetric with two engines out for practice. One engine out wasn't even considered assymetric. We used to practice two engine go arounds which had to be handled carefully due to the size of the rudder. We had a increasing scale of speeds at which certain power settings could be used. On initial thrust application, we could only use 95% on the remaining two IIRC.

And the RAF Nimrod flys around on two engines for a large part of it's life. The crews practice twin engine approaches assuming that the shut down engines can't be re-lit. And of course in the eventuality that one of those fails, they practice single engine go arounds!
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Old 7th Jun 2008, 04:46
  #33 (permalink)  
 
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Reverse Thrust

DW, My comment was in support of Stilton who had disagreed with your statement that "it makes no difference to landing distance and saves significantly on brake wear" if idle reverse thrust is used rather than full reverse. Qantas SOP's did not forbid the use of Full Reverse and, in fact, specifically stated that if airmanship dictated the use of full reverse it should be used. A small, but significant point also in the Qantas accident was that the F/O was the handling pilot and had initiated a go-around. The Captain, when the wheels touched, decided unannounced to cancel the go-around and conduct a full stop landing. In so doing, he moved only three of the four thrust levers to "idle", leaving one in the advanced position it had been placed by the F/O when initiating the go-around. This engine reached 1.50 EPR whilst the remaining engines were at idle before it too was retarded to idle. The decision to cancel the go-around and the unannounced taking over by the Captain only added to what was already an unsatisfactory situation which had developed early in the approach. Incidentally, full pressure manual braking gives more braking effort than does Max Auto Brake. I have studied the report closely, due in part to the fact that three of my family were on the flight. I would thoroughly recommend it as required reading to any pilot.
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Old 7th Jun 2008, 05:39
  #34 (permalink)  
 
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Old Fella, from another old fellow

That was just the excellent response I was looking for.

I flew 4 engine heavy freighters for 11 years. If there was any doubt concerning the use of reverse we would use it. We always selected full reverse on a wet or damp runway.

Spooled up engines, selected to reverse, also gave you a secondary steering option, if for some reason, the full use of the primary control did not have the desired effect.
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Old 7th Jun 2008, 06:09
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Braking is type specific. The 744 with 16 carbon brake units brakes very differently to an aircraft such as an A320. I can't remember the actual figures my company used, but the in flight figures available assumed a wet runway and using autobrake. The only difference was that we would tend to use 2 for a dry runway and condsider 3 for a wet. IIRC, the figures didn't metion full reverse, so the policy of using reverse idle was used. And the accident report alludes to the fact that the Qantas flight training department was teaching this as well so it's safe to say that it was Qantas SOPs. The crew thought they were landing on a only wet runway - so they used their SOPs. Had they realised that it was contaminated (the clues were there) the procedures would have been different.

My comment was to point out that use of reverse idle is common on 744 pax operations.

I have studied this accident thoroughly as well - I was flying the 744 at the time and a friend of mine was part of the subsequent Boeing inquiry. I would say that as in most accidents there was a chain of events leading up to the crash and it could have been broken at any time. But the Commander's decision to stay on the runway was the main cause. If the PF had initiated the GA correctly by pressing the TOGA buttons, it probably wouldn't have happened, but the Commader's closing three of the thrust levers sealed it. The PF wasn't aware that the autobrake had disarmed when he advanced the levers and his slow recognition of the lack of decelleration, lack of the use of reverse thrust having landed fast and long meant the eventual outcome was almost a certainty.
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Old 7th Jun 2008, 06:33
  #36 (permalink)  
 
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747-200 2 eng fail at t/o

On the 747-200, it's all about weight. If you are light enough, you can probably do the whole takeoff on 2 engines
And of course, no obstacles (because then the t/o path would have been calculated to clear them with 3 eng).
Last sim I practiced 340ton, end #4 fails at v1+, eng #3 fails at gear retraction.
If the secone engine fails after the gear is up, it is managable in most weights. You just have to trade altitude for speed, or stay in the ground effect and accelerate. Since flaps are mechanicaly controlled, you can retract them in small increments as the airspeed builds up. I know the book says retract to flaps 1, but even if you get to 10 (heavy t/o is usually with 20) you will be fine.

Regarding braking, on dry runways your concern is avoiding overheating the breaks, and on wet or worse you can brake as hard as you want - and on some cases you will need to.
Our company SOP is on dry: use MIN braking if possible, then Idle Rev is allowed. On wet: use MED and full rev. On contaminated: use MED and full rev, and if the actual runway length available is longer than calculated required distance + 15% company resereve by less then 1,000', then we use MAX braking.
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Old 7th Jun 2008, 06:51
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Stopping effort

Weido-salt, thanks for the vote of confidence, and I apologise to all if I allowed myself to get "off-thread", however I felt I had to respond in the way I did to a couple of comments made by others. I have only ever flown, as a F/E, on multi-engine aircraft which all had reverse capability. On none have I ever witnessed the non-use of reverse thrust, except for limiting it to symmetrically available. DW, the last company for whom I worked rarely used auto-brake, preferring instead to use full reverse and manual braking. Qantas indeed did teach 25 flap/idle reverse technique as the company preferred procedure. I note too that you have not noticed, or chosen to ignore, that the PF was the F/O who initiated the go-around and who had control of the aircraft taken from him, after the mains touched during the attempted go-around, by the Captain who decided to cancel the go-around and attempted to make it a full stop. It was the Captain who left the Number 1 thrust lever advanced and who also did not recognise the lack of auto-brake as a result of the thrust levers having been advanced by the F/O when he initiated the go-around. BTW, Boeing do not endorse the use of only reverse idle and only 25 flap as a SOP. This practice was born of noise abatement and passenger comfort considerations more than anything else. I know carbon brakes are different to steel discs, however regardless of type of brakes the use of reverse thrust to reduce speed and stopping distance is significant and, if available, should be used. As I previously noted, the facility is not put in place for no good reason.
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Old 7th Jun 2008, 08:36
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Different techniques for different aircraft. I've also flown 747 classic freighters with steel brakes (often into Don Mueng 21L - that very runway as it happens) and the technique we used (full reverse, leaving the brakes to the last possible moment using the whole runway length) was all about keeping the brakes cool enough to effect a 60 minute turnaround having just landed at 285 tonnes. A 744 will typically land at about 235 tonnes and the carbon brakes need a very different technique.

Carbon brakes don't care how hot they get. In fact, they are at their most efficient at about 200 degrees C. But what wears them out is the number of applications - or modulations they receive and not how hard you use them. One application on landing stopping the aircraft from 150 knots will wear the brakes as much as on application in taxying slowing from 30 knots to 10 knots. For this reason, the number of modulations need to be reduced for cost effective brake wear.

Autobrake settings (except for MAX and RTO) will deccelerate the aircraft at a measured rate from infrormation derived from the IRSs. To do this, the brakes are modulated. If you apply full reverse after touchdown, by the time the reversers have deployed and the engines spooled up, braking will have been applied. So now, the autobrake will release a bit to keep the decceleration rate constant. When you bring the reversers back to idle, the autobrake will apply the brakes again. The net result is increased brake wear and a landing distance which is the same if you had used idle reverse. Of course you will have hotter brakes, but for 744 pax operations, this isn't usually a problem.

This is the main reason why idle reverse is used. It's not Boeing's advice, it actually comes from the brake manufacturers. My company got BF Goodrich to look at the way we used brakes on landing and they advised that out techniques (using full reverse thrust as per the Boeing flight manual) was wearing the brakes twice as fast as necessary. And at over a million US for a complete set of carbon brakes and discs - the savings are significant. The reverse idle landing technique is common on a lot of 744 operations for this reason. My current employer has 744 freighters and we use full reverse (I don't fly these) - but they are landing a lot heavier that pax 744s tend to. In my time on the 744, I used reverse thrust above idle once.

F25 is used for noise abate in some companies. But others who operated the early 747 Classics such as Qantas and BA had a lot of problems with F30. F30 just deploys an extra section which used to jam - or even fall off in some incidents. BA use F25 and it's use is more historic and "because we always do that" in BA's case. F30 reduced Vapp by 5 knots, I don't know about the LDR. I've always flown with companys which stipulate F30, so I've never used F25.

The way we employed the autobrake was to set the brake in the descent. We had LDR information available to us on the clipboard, but the company route planning department had already decreed that LDAs were suitable at all our detinations to use autobrake 2, with the exception of one little used shorter runway at on detination which requied a minimum of 3. The LDRs were based on wet runways so the use of 2 was applicable, but I seem to remember our SOPs suggested using 3 on wet runways. I never used 4 or Max. Four would have you headbutting the instrument panel, Max (which applied the full 3000 psi with no modulation) would probably have you through the windscreen.

I accept that the distances would be longer for a wet runway because of the less effective tyre adhesion, but we only used figures for wet runways once dispatched so as far as we were concerned - there was no difference. And the 744 FCTM backs this up by saying that autobrake MAX will give a longer stopping distance required that usng full manual pressure on dry runways only.



When I was referring to the PF, I was referring to the F/O. I assumed you were familiar with this fact. The F/O initiated the go around (incorrectly), the Commander reversed the F/O's decision but failed to formally take control. It was the F/O who had control right up to the aircraft came to a halt - the Captain had asked the F/O, "got it?" for which he replied "yea, I've got it" (page 10 and 11 of the report) although both pilots had applied maximum foot braking.
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Old 7th Jun 2008, 09:03
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F/O (incorrectly) commenced a go-around.

DW, I respect your experience and I agree with most of what you say. That said, I still firmly believe that the benefit of using all available means of reducing speed should be used. We all accept, I think, that reverse thrust is at it's most useful in washing off speed initially and thus reducing brake energy required.

I disagree with your comment in the final paragraph of your most recent post however. The F/O did not decide to commence the go-around, he responded to the instruction of the Captain to "go-around". As for the Captains "got it", did he really mean "I have control" or was he asking a question of the F/O, which apparently is the way the F/O took it. The reality is that no-one, including the Second Officer, really knew what was going on. The "Front Office" was in a state of confusion. The F/O even stated that he was pulling back on the thrust levers, (against the idle stop as at no time was idle reverse selected).
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Old 7th Jun 2008, 09:13
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BA 'historic' use of Flaps 25 stemmed from operating 747-100s which tended to suffer from problems including sections detaching when selected. At one time, BA operated 80 747s with a mix of 200s and 400s. The significance of using Flaps 25 v. Flaps 30 was to save fuel and noise (R-R engines required 0.03 EPR less for Flaps 25).
Autobrakes 4 is common for wet runways with a certain SE Asian 747 operator and the difference between 3 and 4 is not that noticeable. I always preferred Flaps 30, full reverse and manual braking for a heavy (300t) freighter landing, especially during the summer in the Gulf area.
One point about the QANTAS accident, is that it was raining so hard that several operators (including BA) delayed departure. That might mean that the runway had a great deal more water on it than a 'wet' runway from ATC reports.It could also mean that the landing distance calculated by "Old Fella" if full reverse and Flaps 30 had been selected, is erroneous.
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