BA 038 : accident LHR

GB: 10 passagers blessés dans un atterrissage en catastrophe attaquent Boeing

LONDRES, 19 nov 2009 (AFP)Dix passagers blessés l'année dernière dans l'atterrissage en catastrophe d'un Boeing 777 de British Airways à Londres-Heathrow vont poursuivre l'avionneur américain, a-t-on appris jeudi auprès de leur avocat.

SEVRIEN a écrit:
"No further comment at this stage" ! Cela pourrait agiter de nouveau le vent, et les courants d'air !

Jeannot a écrit:

SEVRIEN a écrit:
"No further comment at this stage" ! Cela pourrait agiter de nouveau le vent, et les courants d'air !

et faire givrer les cerveaux...

SEVRIEN a écrit:Ne préjugeons de rien !

Mais, ce qui est écrit ci-après en dit long sur des choses qui risquent fort de finir par être révélées officiellement, dans l'enquête d'AAIB !

Cela va surement fermer le clapet aux BCL "intelligents & honnêtes", qui sauront réagir et se comporter dignement !

Mais , bien sûr, cela ouvrira les grandes gueules de ceux qui n'ont jamais voulu comprendre, que nous avons 'connus' sous d'autres cieux !

Lien :
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GB: 10 passagers blessés dans un atterrissage en catastrophe attaquent Boeing

LONDRES, 19 nov 2009 (AFP)Dix passagers blessés l'année dernière dans l'atterrissage en catastrophe d'un Boeing 777 de British Airways à Londres-Heathrow vont poursuivre l'avionneur américain, a-t-on appris jeudi auprès de leur avocat.

A suivre !

SEVRIEN a écrit:Eh, oui ! Ce fut le mystère !

J'observe ces choses :

-- L'avocat / les avocats concerné(s) a / ont eu largement le temps d'éplucher les dossiers & divers éléments qui ont pu être mis entre les mains de Boeing et des autres acteurs, notamment BA & Rolls-Royce ;
-- ces élements doivent être bien plus "complets" / "fournis" que ceux dont nous disposions ;
-- le(s)dit(s) avocat(s) a / ont choisi & / ou conseillé d'attaquer Boeing, et non pas BA et / ou Rolls-Royce !
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"No further comment at this stage" ! Cela pourrait agiter de nouveau le vent, et les courants d'air !

In a final airworthiness directive (AD) to be published Friday, the FAA has rebuffed efforts by both the Air Line Pilots Association International (ALPA) and the US National Transportation Safety Board (NTSB) to acclerate a mandated hardware fix with a 2011 deadline for [Vous devez être inscrit et connecté pour voir ce lien] operators with [Vous devez être inscrit et connecté pour voir ce lien] turbofan engines.
The action stems from the [Vous devez être inscrit et connecté pour voir ce lien] at Heathrow Airport last year in which accumulated ice in the engine's fuel-oil heat-exchanger (FOHE) is suspected of blocking fuel flow to both engines. The same phenomena likely caused a similar in-flight incident with one engine of a Delta Air Lines 777 in November of 2008.
An interim AD issued in March of this year called on operators to follow certain operational guidelines designed to prevent ice from forming, including in-flight and ground measures.

"Ensemble, Boeing (B.) & RR ne voient pas du tout l’utilité de l’AD de la FAA. Cela sera, à leurs yeux « overridden » . ‘dépassé et remplacé’ officiellement, lors de la publication du rapport final de l’AAIB (qu’on pourra attendre encore longtemps). Et, de fait / en réalité c’est déjà le cas. S’il s’était agi de moteurs GE ou P&W, eût-il fallu limiter le « scope » / ‘champ d’application’ à une combinaison soit B777-GE90 ou B777-PW4090 ? Pour les ingénieurs et professionnels « opérationnels », directement concernés par l’enquête, : non ! Car, avec le recul, tous sont d’accord pour dire que :

"(a) si un nombre d’ingrédients, encore à déterminer et à préciser dans leur interaction – lourde tâche-- qui semblent s’être réunis, au-delà de l’aspect carburant / qualité carburant, le problème pourrait « se former » & frapper tous les avions gros-porteurs long-courrier (bi/ -tri / quadriréacteurs… ) indifféremment ;

"(b) pour le moment, le point focal (comme élément proche de la « root cause ») est « water icing » ; « water icing » est ‘stricto sensu’, une forme de contamination ;

"(c) le fait que la contamination pure et dure, au sens conventionnel, ait été mise à l’écart, pour le moment ( « no visible evidence ») & ait cédé la place à « ice acccumulation & release obstructing or restricting fuel flow for reasons not fully known or understood » (je ne cite pas le rapport ‘verbatim’, … je reprends les termes de mon interlocuteur *****) n’empêche pas les travaux de se poursuivre sur ces aspects, et plusieurs aspects de « fuel contamination », mais, au lieu de les examiner un par un, … le ‘focus’ semble être clairement sur un ensemble de facteurs, qui se sont réunis dans ce cas, à un instant précis, sans que ceci ait été le cas sur d’autres avions (y compris, parait-il, mais cela n’est pas encore écrit, sur d’autres itinéraires, tout aussi ‘froids’ ce jour-la, des B777-200ER, à moteurs RR Trent 800 ! ).

***** Et ceci correspond a ce qui est écrit dans le rapport AAIB, et l’article de Flight International [Vous devez être inscrit et connecté pour voir ce lien]"

Furthermore, the Boeing 777 was certificated in 1995 as meeting both the FAA federal aviation regulations and the JAA airworthiness requirements in force at the time.

These regulations required that an aircraft and engine fuel system must be capable of sustained operation throughout its flow and pressure range, and at low temperatures, with a prescribed concentration of water.

However, the current requirements do not appear to address the scenarios identified during this investigation, such as the sudden release of accrued ice, which could lead to a restricted fuel flow.

......(suite) .........European regulators in July [Vous devez être inscrit et connecté pour voir ce lien] by equipping aircraft with a redesigned Rolls-Royce FOHE, a device that is supposed to cool the engine oil while at the same time pre-heating the incoming fuel to prevent any water present from freezing. EASA gives operators 6,000 flight hours from July or until 1 January 2011 to make the fix, whichever occurs first.
The FAA final AD to be issued Friday gives operators the same lead time, with the clock starting in early January (2010).

However, ALPA and NTSB have expressed concerns over potential safety issues during the compliance period.

In comments to the proposed rulemaking, issued in July, ALPA requested that the compliance time be set as soon as six months after the January effective date for the AD as interim procedures call for "an immediate idle descent to melt the blockage" in the case of an engine rollback.
Union concerns include the potential for traffic conflicts during such descents in remote areas with no radar separation.
"This engine rollback is very insidious to the crew and creates the potential for a pilot to be faced with an immediate descent without adequate time to compensate for traffic, weather, or terrain," ALPA states.

Fearing similar incidents, NTSB had called on the FAA to mandate that at least one engine on each affected aircraft be modified with the redesigned FOHE by the end of December this year.

"The NTSB believes that the January 1, 2011 compliance date for installation of the new FOHE is not consistent with the risk associated with the original FOHE design."

The FAA rebuffed both requests however, telling the organizations that the interim operational procedures would "assure continued safe operation until hardware modifications become available".

Investigators believe the [Vous devez être inscrit et connecté pour voir ce lien] which crashed at London Heathrow would have struck the ground earlier, potentially colliding with the instrument landing system antenna, had the pilot not partially retracted the flaps on approach.

The final report into the accident shows that the aircraft's flaps were at 30° before ice flushed through the fuel lines choked off the fuel flow to both engines.

".......before ice, flushed through the fuel lines, choked off the fuel flow to both engines".

As the aircraft descended to a height of about 240ft, the captain retracted the flaps to 25°. The Air Accidents Investigation Branch concludes that this enabled the aircraft to glide an extra 50m (160ft) before touching down.

"The action of reducing the flap setting was prompt...."

".......and resulted in a reduction of the aerodynamic drag, with a minimal effect on the aircraft stall speed," it states.

"If the twin-jet's flaps had remained at 30°, the AAIB adds, it would have cleared the Heathrow perimeter fence......"

"....... but (would have) landed before the ILS antenna, probably resulting in a collision.
"The effects of contact with the ILS antenna are unknown but such contact would probably have led to more substantial structural damage to the aircraft," it says.

"Flight BA038 came to rest at the threshold of ru nway 27L after arriving from Beijing on 17 January 2008. While the aircraft was badly damaged, all of the passengers and crew members on board survived.

After an accident, pilots always discuss whether a crew could have done more even if they appear to have done a good job. It's not usually vicious or critical, it normally feels more like pilots experimenting with ideas about how they might handle a situation like it if they were to meet one themselves.

The crew of flight BA 038, a Boeing 777-200ER [Vous devez être inscrit et connecté pour voir ce lien], were suddenly faced with a technical problem that has never happened before. Not in the effects it had anyway. So any suggestion that they should have been better prepared for it is somewhat wide of the mark.

The presence of some ice in fuel is a known issue, but systems are designed to cope with it. On this day, however, the ice behaved in a unique way, a function, investigators believe, of the particular combination of a long flight in lower than usual outside air temperatures and low average power settings throughout.

The problem showed itself when - on short final approach - the autothrottle system demanded power following many hours at low power settings. As the fuel flow tried to increase, "sticky" ice that had accumulated on the fuel pipe walls was suddenly dislodged and washed downstream, accumulating in a mushy mass on the front face of the fuel/oil heat exchangers which are just upstream of the engines. This restricted fuel flow, denying first the autothrottle and then the pilots the power they were demanding. The engines settled at a setting not far above idle power.

Here's an account of what happened from that point. Heights are above ground level, times are seconds to go to G-YMMM's actual touchdown short of the runway, and autopilot and autothrottle are both engaged. The problems begin at 720ft AGL according to the flight data recorder, but it is a few seconds more before they become apparent to the crew:

· 800ft: Copilot takes control according to BA standard operating procedures;

· 720ft agl/57sec: Right engine fails to respond, then rolls back power to 1.03 EPR;

· 50sec: Left engine retards to 1.02EPR, but both engines remain above idle;

· 600ft/48sec: Copilot becomes aware of a split in power lever positions and, distracted by this, he fails to trip out the autopilot as he had briefed he would do at 600ft;

· 34sec: Crew recognise low speed and that there is a problem maintaining glideslope. They apply manual power but there is no engine response. Airspeed drops further below reference speed and aircraft descends below the ILS glideslop, but the autopilot continues to raise the nose;

· 240ft: captain reduces flap from 30deg to 25deg, which AAIB says stretched the glide by about 50m

· 200ft: Stickshaker operates, copilot pushes stick forward to prevent stall. AIRSPEED LOW master caution warning operates;

· 150ft: Autopilot is disconnected by copilot's action in pushing on the control column;

· 3sec: Capt makes Mayday call;

· 0sec: Aircraft hits ground at a 1,400ft/min (25m/s) rate of descent, 330m short of runway 27L, and slid 372m before coming to rest. Peak touchdown vertical acceleration 2.9g.

So what more could the pilots have done?

The only thing the investigators reveal, from their tests reproducing fuel system ice behaviour, is that if the crew had reduced the low power settings actually to idle, the ice blockage would have dissipated. The trouble is that reducing power at a time when your problem is not having enough thrust is totally counter-intuitive.

So forget that option.

They could have pulled the gear up to reduce drag. Yes, but when the gear broke off at touchdown because of the very high rate of descent, it absorbed some of that vertical energy. Without it, the hull impact would have been harder, the tail would have impacted well before the front fuselage, raising the risk of a fuselage breach. And the aircraft still wouldn't have made it to the runway anyway.

What about the captain's decision to raise the flap from 30deg to 25deg? [Vous devez être inscrit et connecté pour voir ce lien]. Raising it further would risk a stall. Not changing the setting would still have seen the aircraft make it "over the hedge" into Heathrow, and maybe just about clearing the ILS localiser aerial array as well. So doing nothing was an option, but what the captain chose to do definitely reduced the risk.

I couldn't have done better, and I would be pretty pleased if I could have done as well as Capt Peter Burkill and SFO John Coward did on that day in January 2008.

Toucan a écrit:Le "Lawsuit", la plainte engagé(e) par certains passagers ( blessés ) du BA 38 n'est pas contre le motoriste mais contre l'airframer.

Au début, on pouvait penser que ces pax et leurs conseils s'en prenaient au responsable de base, soit le constructeur B.

Ce qui semblait assez logique.

En regardant de plus près la plainte, où ne figurent pas beaucoup plus de sujets britaniques que d'autres nationalités
Et connaissant le "savoir faire" des conseils juridiques ( les avocats )

La logique aurait voulu que le motoriste fut aussi attaqué.

A ce jour, ce n'est toujours pas le cas.

Ces représentants légaux n'ont-ils pas pris conseil auprès de spécialistes aéronautiques avant de déposer le "complaint" ? : Si !

Fowl a écrit:Fresco n'était pas sur cette affaire là....?

Ma mauvaise plaisanterie mise à part, un "award" pour les pilotes de ce 777

Merci Sevrien pour la mise en relief du rapport de l'AAIB

Safety Recommendation 2008-048 (qui remonte au 15 septembre, 2008). It is recommended that the Federal Aviation Administration and the European Aviation Safety Agency should take immediate action to consider the implications of the findings of this investigation on other certificated airframe / engine combinations.

Other engine/airframe combinations Throughout the investigation all of the testing and research into the causes of this accident were conducted on the Boeing 777 / Trent 800 aircraft engine combination, and it is unknown whether other aircraft / engine combinations that have already been certificated might also be vulnerable to this previously unforeseen threat. Safety Recommendation 2008-048 was made to the regulatory authorities on 15 September 2008 to address this

Safety Recommendation 2008-049: It is recommended that the Federal Aviation Administration and the European Aviation Safety Agency review the current certification requirements to ensure that aircraft and engine fuel systems are tolerant to the potential build up and sudden release of ice in the fuel feed systems.

Furthermore, the Boeing 777 was certificated in 1995 as meeting both the FAA federal aviation regulations and the JAA airworthiness requirements in force at the time.

These regulations required that an aircraft and engine fuel system must be capable of sustained operation throughout its flow and pressure range, and at low temperatures, with a prescribed concentration of water.

However, the current requirements do not appear to address the scenarios identified during this investigation, such as the sudden release of accrued ice, which could lead to a restricted fuel flow.

The investigation has established that the risk from fuel system icing is complex and is dependent on a number of interactions that are not fully understood. Much of the current industry guidance is based on research undertaken over 50 years ago and since that time civil aircraft have become larger, fly for longer periods and incorporate new technology and materials. In order to improve guidelines for the design and testing of aircraft fuel systems it will be necessary for the aviation industry, led by the regulatory authorities, to undertake a number of co-ordinated research projects. The first step would be to understand how ice forms in aviation turbine fuel and the properties of this ice.