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OutOfRunWay
4th Jun 2008, 13:34
Hello, all you four engine drivers out there..

Can you please tell me if on your type there is any chance at all of it flying with two engines gone after V1, and if yes, at what weight and with how much runway eaten up?

regards, OORW

Notso Fantastic
4th Jun 2008, 13:42
How about explaining the basis of your query so one would know how to answer. Are you a layman, flightsimmer, private pilot or airline pilot? This is a professional section- couldn't you perhaps phrase the question a bit better- you may be offended if the answer comes in the same vein!

weido_salt
4th Jun 2008, 13:50
Depends on the aircraft weight and speed. If the aircraft is clean and you have speed, it will fly quiet well. R of C wont be ballistic but you will stay in the air, if you maintain speed.

BOAC
4th Jun 2008, 13:51
The answer to
1) is yes, and BA occasionally practised it in the sim for what that is worth
2) Not a lot
3) No idea

From a 2 engined driver who asked a four-engined (BA) driver. If your question is on issues around the BRU crash I would be certain it would not fly.

PEI_3721
4th Jun 2008, 15:47
is any chance at all of it flying with two engines gone after V1,

Yes, providing the aircraft is flown at or above Vmca2.
In those aircraft which are allowed to dispatch with an engine inoperative (ferry flight) this is the basis of the take off calculations. The takeoff speeds are chosen so that V2 >= Vmca2.
There may be specific handling procedures when on the runway to accelerate the three good engines to mitigate the effects of Vmcg1, i.e. two engine roll, the third engine accelerated at higher airspeed. Calculations also take into account take off / climb weight, which generally is not a problem for ferrying.
In some aircraft types / situations there may be a small period of risk if an engine fails after V1 but before V2 (Vmca2). At this point probabilities come into the equation e.g. is the failure an asymmetric or symmetric engine, will it occur between V1 and V2. IIRC there are differing certification standards in this area, i.e. some authorities allow the risk, others require V1=V2>Vmca2.

The requirements and resultant probabilities in certification are the bases of not considering a four engine take off with two failing at a critical stage of take off. This is not to say it will not or has not happened, but it is sufficiently remote not to worry about (train) at a critical stage of flight. Where such failures have occurred some crews have been able to mitigate the assumptions of certification e.g. IIRC at BAe146 lost 2.5 engines shortly after rotate (TNT, Rome, Geese??).

411A
4th Jun 2008, 17:22
Depending on weight (mass for you European folks), altitude, and ambient temperature, it is possible to contine the climb, with two engines failed, on the same side.
Possible with the B707, and B747.
An example.
Circa 1985, location JED, type B747SP.
Max AUW, departing 34L, ambient temperature 28C.
At 200 agl, severe vibs from number two.
Number two throttle retarded, vibs decreased (as would be expected).
Throttle advanced again (bad idea) at 400 agl.
Severe vibs again from number two, then bang.
Number two now finished, and bits from number two migrated to number one.
Number one still producing rated thrust, however the F/E notices that number one fire pull handle red light is eluminated, but no fire bell.
Without saying anything, F/E now acts on his own, and pulls number one fire pull handle.
Resultant configuration: 800 agl, on two engines only (3&4).
Captain (PF) starts slow descent, requests flap retraction on speed schedule, requests immediate fuel dumping.
Clean speed reached at 200 agl, and a very shallow climb established, for a return for landing.
Aircraft landed 34L, without futher incident using reduced flap setting.

As can be seen, a failure of two engines in the immediate climb after takeoff can be accomplished successfully, if flown correctly.
Very doubtful with two engines failed while on the runway...at all but the lowest of weights.

point8six
4th Jun 2008, 18:23
B747-200 simulator:-
Wt 280,000kgs X-wind 10 kts, temp +5C Nacelle anticing 'on', sea level airport (no terrain).
No 1 failed at V1 +5kts and No 4 failed at Vr.
Gear up and climb of 200-300fpm to 1000'aal. Level flight clean-up.

B747-400 simulator:-
Wt 380,000kgs, wind calm, temp +28C sea level airport (no terrain).
No 4 failed at V1+5kts and No 3 failed at 800' rad.alt.
Slow descent ( trading alt. for accel.) and flaps retracted at bug speed -5kts. Lowest alt. reached 400' rad.alt. Accelerated to 280 kts to turn into live engines (not possible at Flaps up speed).
In both cases, fuel jettison (2000kgs per min.) not used until after flaps retracted.
For either 747 types, flight following failure of both adjacent engines at between V1 and Vr would probably be impossible - but I stand to be corrected by anyone who has had time in the sim to experiment.:ok:

john_tullamarine
4th Jun 2008, 21:56
F/E now acts on his own ...

Had a similar incident on the Electra years ago where the F/E pulled the handle (in the blink of an eye and during the landing flare, mind you) when a prop decoupled.

Post flight, we thought that his action showed initiative .. but that it might have been better had he consulted with the pilots prior to doing something which could have had significant consequences.

I presume that a like discussion occurred after your example ?

411A
5th Jun 2008, 03:00
I presume that a like discussion occurred after your example ?

Oh yes, discussions/actions followed.

F/E
Immediately terminated, with an exit visa issued within 48 hours.

Captain.
A very experienced guy on B747 and TriStar aircraft, received a company commendation, and three months additional salary.
He retired to Australia two years later (he was a native Australian).
A superb airman and well respected by all who knew him.

F/O
Complained to the B747 fleet manager that he was not kept in the 'loop' with the Captains actions.
Fleet manager read the riot act to this guy, and sent him back to the simulator, with a suggestion that he RTFB on two engines inop scenarios.
The Captain also stated that he thought it was inappropriate to hold 'ground school' for the F/O, while trying to keep the blue side up and avoiding terra firma.
Fleet manager agreed and in addition, sent all local F/O's to the sim for additional engine inop scenarios.
All B747 F/E's...likewise.

The company was very fortunate to have, in command of that particular flight, an experienced Captain who positively knew what he was doing.

OutOfRunWay
5th Jun 2008, 08:37
To clarify my original query: im a two engine bus man. Never been anywhere near a quad.
Yes, the question was inspired by the BRU accident, and also by another thread about tri-engines, and how well they will fly after two out.

I am aware that a two engine out on takeoff is not considered for planning. I was only after a general idea and perhaps a few stories:ok:


The answers from 411a and point8six are the sort of thing I was hoping for.

Thanks people!

FE Hoppy
5th Jun 2008, 08:46
What has 2 eng out got to do with BRU? There is a very long thread about stopping after V1. I think it's more relevent.

Old Fella
5th Jun 2008, 12:14
Have a read of www.dm.af.mil/news/story.asp?id=123075451 (http://www.dm.af.mil/news/story.asp?id=123075451) for a recounting of a USAF C141 Starlifter going double asymmetric at about 200'AGL after take-off from RAAF Base Richmond in 1977. Their problem was compounded by a fire in the cargo compartment caused by hot turbine blades setting the load on fire.

Taxi2parking
5th Jun 2008, 13:50
Friend of mine was giving a check ride to one of our 'old and bold' Standards guys on the C-130 sim. He said that this guy was so bloody good that having he though he'd try a double EFATO, with both engines on one side, just after rotate. This didn't even cause him to break into a sweat so he failed another one...he still couldn't make him crash - don't think they even publish a Vmca for that one...



Poor old 411A, in all you're stories an experienced Captain always saves the day whilst battling against incompetent F/Os and F/Es. Still it's always a happy ending with the unfortunate individual or individuals being chewed out or sent home. After of course being put right by their more experienced four striped betters......Strange though because so many of the F/Os and F/Es I've flown with have proved to be excellent operators who do much to enhance the safety of the flight. Then again I suppose if you train people well, have high expectations and place trust in them they are less likely to disappoint. Maybe all these companies you work for should try that.....:eek:

finncapt
5th Jun 2008, 15:44
We used to try 2 engine out on T/O on DC10 simulator. It could be done but just and probably not at high weight.

There was a graph/table? if I remember correctly which plotted the level off altitude against weight - it was sometimes below ground level!

Other DC10 drivers may remember better than me.

On 26 at Gatwick, at high weight, I thought the best course of action was to call finals at Dunsfold!!

finncapt
5th Jun 2008, 15:48
Didn't a VC10 lose two over White Waltham and return in the early 70's.
I think Johnny Smurthwaite was the skipper - a nice man.

411A
5th Jun 2008, 17:12
....in all you're stories an experienced Captain always saves the day whilst battling against incompetent F/Os and F/Es.

And, why not?
That is what the experienced Captain is there for, in my opinion.
He commands the ship, and saves the day when it all goes pear-shapped.
You can train junior guys all day long in the sim for six months, but nothing is a substitute for line flying, done on a regular basis, with an experienced Commander at the helm.
So-called 'new' training methods, including 'enhanced CRM' for the junior guys is positively no substiture for handling experience, when the chips are down, and you are in a dire emergency situation.
You have to positively know the drill, and action accordingly, otherwise one could end up dead as a doornail...along with a whole lot of other folks.

This is not to say, however, that many First Officers aren't up to the task.
Many are, as demonstrated in the same airline when three of four hydraulic systems were disabled in an L1011, and the fourth with slightly more than half of system fluid remaining, with the First Officer flying (only his column active), landed enroute, successfully...just like he was trained to do.
A superb accomplishment.
He was also a senior First Officer, shortly scheduled for command upgrade training...which he completed most successfully.

Meikleour
5th Jun 2008, 17:31
In the distant past I flew a 3-eng ferry flight in a Vanguard, also sim trained for 3-eng ferries on both the B747-200 and A340-300

During these exercises the two engine inop performance is taken into account. Not surprisingly this results in very restricted take-off weights and high V speeds. At the normal weights used on these aircraft it is therefore fairly obvious that only multiple PARTIAL power losses and or sufficient height to trade will make such scenarios flyable.

Old Fella
6th Jun 2008, 01:41
411A, I know you have spent many years on the L1011 and I am sure you are a very experienced Commander. You do, however, seem to believe that it is only the experience of the Captain which saves the day when things go pear shape. In my experience it has often been the F/E who has the most experience on a particular aircraft type and most Captains and First Officers seemed to appreciate that fact. Of course the Captain will in most cases be the one who safely puts the aircraft on the ground. Equally, in most cases, he will have been greatly assisted by his F/O, and his F/E if one is part of the crew.

If you really believe that it is always the Captain who alone is the great saviour then I am pleased that I have never had the pleasure of having to crew with you. Again, in my experience, the best people with whom to fly are those that believe that all the crew are there because they have a part to play in the overall operation and can make a valuable contribution in all circumstances.

Geez, I'm pleased I've got that off my chest, I feel so much better now.

PS. I'm talking about fully trained F/E's with considerable experience as a Ground Engineer before they trained as a F/E, not a pilot placed in the F/E's seat.

411A
6th Jun 2008, 02:06
411A, I know you have spent many years on the L1011 and I am sure you are a very experienced Commander. You do, however, seem to believe that it is only the experience of the Captain which saves the day when things go pear shape.

Sometimes, it is the only factor.
I'm talking about fully trained F/E's with considerable experience as a Ground Engineer before they trained as a F/E, not a pilot placed in the F/E's seat.

Yep, couldn't agree more.
However, when these few F/E's act on their own, and start actioning fire pull handles without good reason, everyone ends up in trouble, make no mistake.

Definitely not a good scenario.
This is precisely why fleet managers have heartburn.
Big time.

Old Fella
6th Jun 2008, 03:18
411A, Surely you do not contend that it is only F/E's who make mistakes. Of course, any F/E who would take it upon himself to "Fire Handle" an engine without (a) being requested to do so, and (b) getting confirmation that he has the applicable "Fire Handle" is out of order. 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. That particular accident was the result of a total lack of planning and lack of communication during the landing and attempted "Go-around" come "Full-stop". There are numerous instances where the PF, whether the Captain or not, has made a mistake which led to the loss of an aircraft and people. Fortunately, we are not robots and are all capable of getting it wrong. To suggest that only the Captain can "save the day" is way out of line, regardless of how many years experience the Captain may have. Believe me, I have flown with some Captains (thankfully very few in number) who give everyone heartburn, not just their fleet manager.

Dan Winterland
6th Jun 2008, 03:59
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.

411A
6th Jun 2008, 04:15
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.'

weido_salt
6th Jun 2008, 04:44
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.

Dan Winterland
6th Jun 2008, 05:25
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/investigation_reports/1999/AAIR/pdf/aair199904538_001.pdf

finncapt
6th Jun 2008, 08:47
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.

Dan Winterland
6th Jun 2008, 10:58
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).

Old Fella
6th Jun 2008, 11:15
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.

rhythm method
6th Jun 2008, 11:55
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! :eek:

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!

Taxi2parking
6th Jun 2008, 13:35
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....:\

stilton
6th Jun 2008, 18:49
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.

Old Fella
7th Jun 2008, 03:04
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.

Dan Winterland
7th Jun 2008, 04:19
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!

Old Fella
7th Jun 2008, 04:46
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.

weido_salt
7th Jun 2008, 05:39
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.

Dan Winterland
7th Jun 2008, 06:09
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.

747dieseldude
7th Jun 2008, 06:33
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.

Old Fella
7th Jun 2008, 06:51
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.

Dan Winterland
7th Jun 2008, 08:36
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.

Old Fella
7th Jun 2008, 09:03
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).

point8six
7th Jun 2008, 09:13
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.

Dan Winterland
7th Jun 2008, 09:27
I see your point, but I was explaining the philosophy behind use of reverse idle for those not conversant with the use of carbon brakes. And I'm not saying I agree with it. To my mind it's a technique that was invented in the accounts department and not the flight training department. But in modern aircraft ops, reverse is less necessary that it used to be in normal situations.

I now fly the Airbus - and although we use reverse idle most of the time, we use full reverse on wet/short/high and tailwind runways. But the Airbus autobrake system is a bit different to the Boeing's and the carbon brakes wear differently.

When I sais the F/O incorrectly initiated the go around, I was referring to the technique he used. He advanced the thrust levers manually rather than pressing the TOGA buttons. He did this to initiate a faster go around according to the report. But by not pressing the TOGA buttons, the aircraft would still be in flare or rollout mode, he would have to look through the flight directors and fly the go around manually - including the navigation as the flight plan would not have sequenced the go around track. What he should have done is pressed the TOGA buttons and moved the levers manually thus overriding the motor clutch if he wanted a faster advancement. And if the aircraft had gone into the full go-around, the Commander would have felt far less inclined to stay on the runway.

If you press the 744s TOGA buttons once, you get a go around with a climb of 2000fpm. Press them a second time, you get full rated TOGA thrust.





As a matter of interest, Airbus was considering offereing the A320 family without thrust reversers as an option a few years ago. I bet that with fuel prices as they are, the idea is being dusted off again!




An afterthought: If the F/O had pressed the TOGA buttons, the autothrust would have been re-engaged and the thrust levers would have gone forward again. If they had stayed on the runway, they would have gone off the end going a lot faster.

Old Fella
7th Jun 2008, 10:33
Point8six, the figures used were not mine, they came directly from the ATSB report. I would hope they are authentic.

411A
8th Jun 2008, 03:11
Hmmm, it would appear to me, Old Fella, that you were, at one time, a rather senior Flight Engineer.
Having said this, it would be wise for you to remember that Flight Engineers are third-in-command...after the pilots.
Like it or not, that is the way it is....and shall remain.
Just the facts..

mutt
8th Jun 2008, 05:06
Old Fella, as a B744 operator, we are changing procedures to F25 and idle reverse on the recommendation of the IATA Fuel Conservation Group..... If you were a FE, you wouldnt have operated the B744, therefore dont make the mistake of believing that its "stopping capabilities" are the same as the Classic.

Mutt

Old Fella
8th Jun 2008, 06:21
411A, I have never questioned who is in command. Of course it is, and has to be, the Captain unless he becomes incapacitated, either physically or mentally. My point has been that your comments inferred that only F/O's and F/E's were capable of making mistakes and that only the Captain can save the day. I have not inferred that you personally have made mistakes, but unless you are a robot you are as capable of making a mistake as any other human. Yes, I am a retired senior F/E and I had the pleasure of flying for many years with a multitude of extremely able pilots. I also had the displeasure of flying with a very small number who were not only less than confidence inspiring, but also were a "One man band" which, in my view, is not only unpleasant but at times dangerous. Incidentally, I never gave any thought to being "third-in-command", but rather to being a member of a team able to make a contribution to the conduct of the flight. The Company must have felt that to be the case, they paid us the same rate as the F/O's. Your comment that F/E's are "after the pilots - like it or not" is uncalled for and petty. Mutt, thank you for stating the obvious regarding my not having operated the B747-400. I do however understand the difference between the brakes on the Classic as compared to the -400. My basic argument is, and has been all along, that the use of reverse thrust contributes as much as 20% of the speed reduction effort on a contaminated runway and should be used. That your company has chosen to use 25 Flap and idle reverse as a fuel conservation measure is their choice and in most cases probably very reasonable in terms of cost savings. The unfortunate thing with the QF accident was that nobody ever even considered the use of full reverse and 30 flap, and at least one of the crew had never witnessed a 30 flap/full reverse landing.

stilton
8th Jun 2008, 07:19
Your point is extremely valid and well made Old Fella, regardless of how much fuel is saved or brake wear improved, use of idle reverse is, in my opinion, negative training , operators may unconsciously be setting up a situation where these habits may lead pilots to not avail themselves of full reverse thrust capability when needed.


As to 411a, very few crewmembers other than himself of course ever measure
up to his 'standards' you are correct in your statement that in the cockpit, whilst the Captain is always in charge you are a vital member of the team.
His threads always relect a theme of 'but for the Captain all would have been lost' he has a total lack of respect for other crewmembers, very much a 'one man band' and I pity the people who have to work with him.


I am fortunate enough to fly with some of the best First officers in the business, as part of my brief though, I always mention, and emphasise, we ALL make mistakes, what is important is for one of us to catch it, point it out (always with tact if time allows) and correct it.


Later, when I do make one of my mistakes! I make a deliberate point of thanking him /her for pointing it out, this really sets the tone and lets them know I 'practice what I preach'


It is always a pleasure to hear from professionals such as yourselves with such valuable experience.

point8six
8th Jun 2008, 10:05
Old Fella - I am not disputing the accuracy of your (ATSB) figures, but as in all planning cases, they are theoretical and probably based on poor braking conditions. However, taking a practical view, those figures may be erroneous given the 'deluge' of the monsoonal rains at that time causing flooding on hard surfaces. What is not disputable, is the poor planning and badly executed landing that resulted in the over-run. (Also not disputable is the thread creep)!
Getting back to the original subject, 747Dieseldude, at 340 tonnes, you would have had a V2 in excess of Vmca( I no longer have 747-200 manuals, but is 157 knots close for Vmca?). If you were below Vmca, then directional control might only be possible by throttling back the good outboard engine, which would compromise the climb ability. Still, an interesting manouevre requiring accurate flying :D.

weido_salt
8th Jun 2008, 13:04
stilton

Very good post indeed. In my brief I do the same myself, where I encourage input no matter how trivial.

If a person as Captain comes across as agresive, snappy or very arrogant for example, he/she has immediately built a wall, which could stop communication no matter how trivial especially from a not so assertive F/O. Below is a case in point.

Decades ago when a certain airline landed at a new airport. So new in fact it was not yet open, except for their a/c opening it temporally. To cut a long story short, the Captain had been "riding" the f/o, who was leaving the company very soon anyway, lined up for the approach at the wrong airport. That F/O knew they were about to land at the wrong airport but, due to the captain's nature, kept his mouth shut and let him get on with it. The Captain had built a wall between him and the F/O for input. Yes the F/O was at fault to of course but was in a position to avoid very red faces.

Human nature? If you bully people, they will react, one way or the other.

Dan Winterland
9th Jun 2008, 05:44
Indeed! It's Threat and Error Managemen (TEM) which is replacing CRM as the latest flight safety trend. Not that 411A will be following that philosophy. He hasn't got to CRM yet!



The continued use of reverse idle is flight safety factor for the reasons stated, and when I flew the 744, it was so rare to use it I could easily imagine not considering it even when needed. Now, the company I fly the A320 for require us to select full reverse on landing even if idle has been briefed. If idle is to be used, the thrust levers will be immediately advanced to the reverse idle stop before they have spooled up. This doesn't harm engines controlled by FADEC and ensures that the reverse idle setting is selected - it's sometimes a problem finding the reverse idle stop on the A320 as there aren't separate reverse levers. The thrust levers are moved into the reverse section past idle after latches have been lifted. This technique also has the added benefit of making the crew 'full reverse minded'.

On Qantas 01, the crew believed the runway was merely wet when in fact it was contaminated (despite clues to the contrary) which led them to believe reverse idle was satisfactory. And the PF didn't select any revers thrust - let alone full reverse thrust.

Old Fella
9th Jun 2008, 06:14
Stilton, thank you for your support. I have not wished to "throw stones" at any other poster to this forum, however I find it disappointing that some seem to dismiss any input from other than a fellow pilot. My argument has been put in this thread and I really do not have anything further to add other than that I look forward to more interesting threads to follow and to contribute to if I feel I can say something of value.

john_tullamarine
9th Jun 2008, 06:24
Perhaps we can all accept that there is a range of styles across the brotherhood of pilots and that all crew members ought to be looking at their own contributions and the contributions of their colleagues for the common good .. ?

Probably not all that productive to dwell upon perceived shortcomings of this or that individual ?

stilton
10th Jun 2008, 06:11
I spent 19 years in the (respectively) Second Officer and First officer seat before I upgraded to Captain, I always took note of the Left seaters I wanted to emulate and, perhaps more importantly those I wanted to be nothing like.

A safe cockpit is one in which everyone is communicating with each other with no hesitation, this most certainly includes Flight Engineers.

As you know well Old Fella, the best Captains lead by example and almost never even have to mention their authority.

I don't know of any Boeing Or Airbus certified for single pilot operation.

All the very best Old Fella.

411A
10th Jun 2008, 08:39
Probably not all that productive to dwell upon perceived shortcomings of this or that individual ?

Well said, JT, yet I expect this will be ignored to some degree.
Why?
Simply because a few apparently are looking at certain statements by some, who positively know what they are doing, and follow the AFM...versus...those that might well have come from 'other airlines', whose operations were tailored for their specific desires.

As in...'Well, when I was at BA, we did it this way'.

Quite frankly, I couldn't care less.
Nor does the company.

If some folks bring these attitudes to the present, they are politely requested to shape up or ship out.
If they continue, a 'Don't come Monday' letter is issued.

In our particular case, Lockheed issued quite precise recommendations/instructions on how to operate the airplane and the present airline management is simply not interested in accomodating those who think they 'know better'.

Simply because, these few folks do absolutely not know better, as has been proven time and again.