Cargolux B748 substantial structural damage

[SMOC]

Accident: Cargolux B748 at Libreville on Nov 24th 2014, hard landing (http://avherald.com/h?article=47ed9485&opt=0)

Accident: Cargolux B748 at Libreville on Nov 24th 2014, hard landing

By Simon Hradecky, created Tuesday, Dec 16th 2014 20:14Z, last updated Tuesday, Dec 16th 2014 20:40Z
A Cargolux Boeing 747-800 freighter, registration LX-VCC performing freight flight CV-7101 from Luxembourg (Luxembourg) to Libreville (Gabon), landed in Libreville at about 19:30L (18:30Z) but touched down hard. The aircraft rolled out without further incident and taxied to the apron.

The aircraft continued its schedule returning from Africa to Luxembourg on Nov 26th, performed rotations from Luxembourgh to Shanghai (China) via Russia and back, flew from Luxembourg to Hong Kong (China) via the United States and back, and finally was removed from service in Luxembourg on Dec 2nd 2014 after substantial structural damage was detected as result of the hard landing in Libreville.

The damage is going to be assessed by a Boeing maintenance team to decide whether the aircraft can be repaired, preliminary estimation suggests the aircraft will be repaired.

Libreville features a runway 16/34 of 3000 meters/9850 feet length.

Any ideas on the location of the damage, would like to know if it could only be found by a detailed inspection such as removing panels, extending flaps etcetera, I gather it was not reported by the tech crew and was checked as a result of downloading the QAR.

[JammedStab]

I heard that it was a 4g landing. New FO.

[tdracer]

Reported as 3.14g, "initial inspection on-site was performed by local mechanic with nil findings"
Subsequent A check inspection found several deformed skin bays.

[kungfu panda]

3.14g is very very heavy, what does that equate to in terms of sink rate? I guess that depends on the weight.

[Flightmech]

As 30N30W says........
3.14g that's damn heavy, back breaking?

[Sop_Monkey]

Poetic if you ask me. F/O? Where was the Captain, asleep or is responsilitty delegated these days?

[silverknapper]

I guess I would have thought it would also tell the crew. Do no heavy boeings do this? Just curiosity.

[atlast]

3.14g? Sounds like a Pi ~ lot problem to me ;)

[RedBullGaveMeWings]

How long on average does it take a pilot new to the 747 to get used to the eye height from a 737 or other aircraft with lower flight deck?

[Sop_Monkey]

Not long. Same Technic for any aircraft with audio/visual radio altimeter read out. 10 - 5 feet approximately, just close the throttles on a properly trimmed ILS and you should get a reasonable landing. Certainly not 3.14 G. Ground effect will arrest the R of D to an acceptable level, without a flare. IIRC.

[WhaleDriver]

It's safe to say that this was a dive into the runway. If stabilized and on glideslope at 800 FPM, you can not flare at all and not do damage. I had an FO drive into the ground at ANC one morning. I wrote it up but was told, if I did not get "Sink rate", I could not have had a hard landing.

[final06]

It is safe to say that most of the comments above demonstrate that the authors have no clue what they are talking about.

There is interesting reading in Boeings' AERO magazines.
(Try 'search' for overweight landing and also for conditional maintenance inspection procedures.)

It was a line training flight with a new F/O on his first flight on a 747.
The Cpt/Line trainer himself intervened during the landing, took control of the a/c and produced the 3.14g landing. A techlog entry was done. However maintenance could not find evidence of damage on their first inspection.

Btw
Retarding throttles on a 744/748 at 10-5" is too late.

Cheers

[Sop_Monkey]

Beg to differ.

I much preferred to touch down with the engines spooled as much as possible, to maximize the effect of reverse thrust after touch down. Engaging reverse when the nose wheel has touched is too late. I used to try and save my wheel brakes for the time I may really need them. The 744/748 is just another heavy Boeing aircraft, or am I on the wrong page?

I honed these skills when flying cargo before I became an SOP Monkey. You know, when pilots were able to think for themselves.

QF years ago have a fuel saving policy of engaging revers idle only and it cost them a hull.

[Intruder]

Wrong page.

On the 744, the N1 has to be at or near idle, as well as the main gear untilted, before the reverser locks unlock. Having the engines spooled up at touchdown actually delays reverser deployment.

On a nominal approach, the throttles can be brought to idle at 50', and the flare (minimal as it is) done at 30' to attain a smooth landing in the first 1000' of runway. The nose is brought down as the reversers deploy, and max reverse (if used) applied when available.

[Sop_Monkey]

Ok I stand corrected on that.

On first generation aircraft of the sought, we weren't hamstrung by the N1 restriction.

[Tank2Engine]

Beg to differ.

I much preferred to touch down with the engines spooled as much as possible, to maximize the effect of reverse thrust after touch down. Which SOP is that? Turboprop/cowboy SOP? In most airlines, touchdown with thrust on is considered bad airmanship and a big no-no. Thrust on touchdowns can be smoother (good for some people's ego I guess) but you tend to float and as Intruder pointed out, it delays reverse thrust selection.

I used to try and save my wheel brakes for the time I may really need them."My" brakes? :rolleyes:

For what it's worth, Libreville has quite a bump/upslope in the TDZ for runway 16 and at night it can be a bit of a black hole approach.

[tdracer]

On the 744, the N1 has to be at or near idle, as well as the main gear untilted, before the reverser locks unlock. Having the engines spooled up at touchdown actually delays reverser deployment.

Not quite - on the 747 the gear tilt has to set "Weight on Wheels" (WoW - which is based on gear tilt) true before the reversers can be deployed. But there is no N1 logic in the reverser controls on the -400. At some point the actuators may have difficulty in overcoming the aero loads, but you'd need to be well above idle before that came into play.
The 747-8 does have N1 logic that would prevent reverser deployment with N1 too high (structural reasons), but it's quite high (~75% N1 IIRC) and would only be expected to come into play during an RTO.

[Sop_Monkey]

Tank2engine.

What SOP is this? https://www.youtube.com/watch?v=bnBr3enzW1I SPS? (small p***s sydrome)

This clown not only risked the lives of all on board, but many on the ground by getting "his rocks off" by performing an AH stunt like this. If this is the behavior, not to mention the caliber at the "top" of the food chain at this outfit, there isn't a lot going for a lowly F/O on his first revenue landing is there?

[JammedStab]

How long on average does it take a pilot new to the 747 to get used to the eye height from a 737 or other aircraft with lower flight deck?

The 747 has to be one of the easiest jets to land in normal conditions. I have been in the jumpseeat of a -400 with an ab initio guy doing his first two landings on the line after sim(and touch and goes). Total time...about 300 hours. First two landings...very, very nice. Last aircraft flown...a light piston twin probably more than half a year earlier.

On this thread we are talking about a 747-8 but a 747 test pilot told me that it was modified during the whole design process to fly as similar to the -400 as possible in terms of handling. Apparently took quite a bit of work to design these features into it.

And of course, there could be local conditions that had an effect on the Cargolux incident.

[main_dog]

Retarding throttles on a 744/748 at 10-5" is too late.

I'm not sure I agree, depends on many factors including engine type. I usually look at my speed one last time before commencing the flare and then reduce thrust accordingly, it might all come off by shortly after 30' (if, say, light weight, at or above Ref+5 and flying an engine with lots of residual thrust like the PW4062) or at the other extreme I may keep some of the thrust in until touchdown (heavy, gusty conditions and energy level low, especially on a Rolls Royce RB211 engine with its alarming lack of residual thrust).

Straight from our Boeing B744/748 Flight Crew Training Manual:

After the flare is initiated, smoothly retard the thrust levers to idle, and make small pitch attitude adjustments to maintain the desired descent rate to the runway. Ideally, main gear touchdown should occur simultaneously with thrust levers reaching idle.

[MD11Engineer]

SOPMonkey:
Ok I stand corrected on that.

On first generation aircraft of the sought, we weren't hamstrung by the N1 restriction.

I have worked on all Boeing jets since 707 with the exception of the 777 and the 787 and am licenced on the 737NG, 747-400, 747-8, 757 and 767 plus the the MD11.
All of these Boeings have a similar mechanical interlock, which prevents the reverse levers to be pulled up unless the thrust levers are in idle (and similarly prevents the thrust levers to be pushed forward unless the reverse levers are down). Another solenoid activated interlock prevents the reverser levers to be pulled above the reverse idle stop if the reversers are not fully deployed.
So you have to pull the thrust levers into idle before you can pull the reverse levers up. Additional interlocks prevent you from depoloying the reversers in the air.

[Sop_Monkey]

main_dog

Agreed. I liked to touch down with the aircraft trimmed. Pull the power off too early and you have a nose heavy aircraft. Nothing too much wrong with that of course but doesn't help the person trying to land, if landing is the problem.

MD11

Agreed.

[JammedStab]

I'm not sure I agree, depends on many factors including engine type. I usually look at my speed one last time before commencing the flare and then reduce thrust accordingly, it might all come off by shortly after 30' (if, say, light weight, at or above Ref+5 and flying an engine with lots of residual thrust like the PW4062) or at the other extreme I may keep some of the thrust in until touchdown (heavy, gusty conditions and energy level low, especially on a Rolls Royce RB211 engine with its alarming lack of residual thrust).



Interesting. I didn't realize that there was a big difference. I have never once kept the thrust on all the way to touchdown and would expect the aircraft to float quite a bit if I did.

But I have never flown the RR version. Now I wonder if that technique of having the thrust levers reach the closed position at touchdown is due to the RR version.

[grounded27]

I gather it was not reported by the tech crew and was checked as a result of downloading the QAR.
http://www.pprune.org/images/statusicon/user_offline.gif http://www.pprune.org/images/buttons/reply_small.gif (http://www.pprune.org/newreply.php?do=newreply&p=8789183&noquote=1)

Usually when hard landings are not reported by the flight crew, Tech has no idea of it unless in the book or reported by ACARS. The 74C had a nasty habbit of telling on the pilots as the fowler flaps would shift and cause some significant destruction upon retraction. A landing as hard as this may have very well created a fuel leak as an indicator, may take a few legs to find on a walk around... Or a self disclosure from someone who experienced it. This report stinks to me.

[wingview]

About a month before this occurrence I saw a 748 also from Cargolux (don't know if it was the same aircraft) making a pretty heavy landing. You could see the tail drop in the flare and 2 huge plumes of smoke (was with a bounce) was the result. I was surpriced it left again after 2 hours which is the normal turn around time I think.

[JammedStab]

Luxemburger Wort - Open-plane surgery for Cargolux Boeing (http://www.wort.lu/en/business/hard-landing-in-libreville-open-plane-surgery-for-cargolux-boeing-54fd81aa0c88b46a8ce55063)

Hard landing in Libreville

Open-plane surgery for Cargolux Boeing

Repair works on a Cargolux Boeing 747 are still ongoing, with some 40 experts on site at a hangar in Findel to help get the aircraft off the ground again as quickly as possible.

According to executive vice president of maintenance and engineering Onno Pietersma, the repairs are progressing according to plan. Boeing experts, as well as local Cargolux engineers and technicians are working on the LX-VCC to repair damage suffered during a hard landing.

The incident took place in Libreville, Gabon, but the extent of the damage was not discovered until nearly two weeks later, during an inspection at the Luxembourg maintenance facilities.

The fuselage of the plane was damaged, with the aluminium shell dented in a number of places. However, the issue was not just superficial, with part of the plane's supporting structure damaged. The main landing gear on the left side also had to be removed and repaired.

The undertaking to repair this variety of issues is no easy feat. In order to transport the 747-8F to the hangar, it was equipped with the landing gear of an old 747-400F. The 76-metre long aircraft, however, did not fit fully into the maintenance hall, and a temporary extension was erected to cover its tail.

Cause of hard landing unclear

The tail fins had to be removed, as they would have been exposed to winds. Through bending forces this could have caused further damage to the hull and made repairs even more complicated.

Thirteen new hull panels need to be installed, with parts ordered from Boeing.

Most crucially, however, the plane's 12-metre keel beam, the Boeing's spine connecting the front with the tail, needs to be repaired. To allow this, the plane has been jacked up.

This also allows for repairs on the landing gear to progress. However, here the airline was faced with another problem. Normally, landing gear repairs are not needed until a plane is around 10 years old.

Because the first 747-8F model was only rolled out in 2010, there are no set procedures for maintenance. Cargolux, Boeing and maintenance and services company Revima first had to develop a new protocol.
By the end of the month, the restored landing gear is expected to be installed.

Still to be determined is where the plane will be varnished.

Also unclear at this point is the cause of the hard landing in Libreville. An investigation is ongoing, Pietersma commented. The main priority, he added, was to get the plane up and running.

“This repair is not unusual,” he said, “it is merely a very big task.”

New 747-8F joins the fleet

While one plane of its fleet is undergoing repairs, Cargolux last week welcomed its 30th Boeing from Seattle, which was greeted in Luxembourg with a traditional water cannon salute.

The LX-VCL features a portrait of Joe Sutter, in honour of the man who designed the 747 in the 1970s.

It is the 12th of 14 747-8Fs ordered by Cargolux to be delivered, and the 30th Boeing overall received by the Luxembourg freight airline in its history.

The delivery brought Cargolux's fleet up to 23 planes, also including 11 747-400Fs.

[7478ti]

Desirable or optimum thrust use or retard in flare, whether on a -100, -200, -SP, 300, -400, or -8, and regardless of engine type, ...can depend on the flight path, energy state at flare, sink rate, flare profile, atmosphere behavior, and engine/thrust state. It is true that the -8 flies just like a -400, which is why landing PACS on the -8 was so carefully worked, with the new flap configurations. However, beyond the standard FCTM landing technique guidance, one would need to see the FDR or QAR, or both, to really understand what happened, or make any reasoned assessment of what went wrong?, or went right? for any particular landing. Further, as for many big jets (without DLC, as the L1011 originally had but was later deactivated), a complicating factor can be the "Cz delta e" derivative (i.e., momentary vertical heave opposite to the control input command), which can cause a slight momentary aircraft vertical response opposite to that originally intended (e.g., a last second brisk pitch pull, to save a landing, can actually make the sink rate momentarily worse before turning the gamma corner). The reverse of this effect is also true, which is why "push landings" worked so well for some pilots on the B727. So in this instance, without both the crew statements, knowledge of the atmosphere, and the FDR traces, it is very hard and most inappropriate to pass judgement. Let's perhaps let the appropriate event investigators figure it out, and give the crew and the airline the benefit of the doubt for now?

[TWT]

QF years ago have a fuel saving policy of engaging revers idle only and it cost them a hullIt cost them a runway overrun.Hull was repaired and kept on flying until it was scrapped at Marana in 2013.

[7478ti]

Having flown each of the key major 747 variants and engine combinations at some point through the -8, it is important to note that each of the B747's flying characteristics are typically observed by experienced B747 pilots as being good and well behaved. Notwithstanding any electronics flight deck differences, pilots typically note that the characteristics vary more within a particular variant, for conditions like very light weight versus heavy weight, or far forward CG versus far aft CG, or for a Vapp and approach trim theta ranging from Vref+5 to Vref +20 (depending on the atmospherics and things like G/S angle used)... rather than highlighting any potential differences between any two particular variant combinations. These observations usually apply to any recent 747 variant from minimum in-flight weight, to MTOGW, and well above MLW (as specifically assessed in some key flight tests), including even for the BCFs and LCFs.

O:)
ti

[ORD]

As of last Monday aircraft is back in service. :ok::ok:

[Bunk-Rest]

yep you really are sick

[Bunk-Rest]

AND YOU ARE A COMPLETE ******

[alldaysushi]

Haven't flown the -8, but the classic and the /400 yes. For sake of ease on thread, Intruder and Md11 Engineer capsulize well.

Both variants were easy landings...as long as the radar altimeter is singing it's

Landing song.

A 3 g landing in any wide body sounds like chopping power
and flaring too high. Would love to hear from a 748 driver
to delineate further.

Safe journeys...Sushi