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Crash G650 essai à Roswell (2 avril 2011)

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Beochien
Whisky Charlie

Crash G650 essai à Roswell (2 avril 2011)

Message par Beochien le Dim 3 Avr 2011 - 4:37

Bonjour !

Un G650 de Gulfstream, avion d'essai, s'écrase au décollage ,4 morts ! 2 pilotes et 2 ingés !
C'est grave pour les pertes humaines, et pour le constructeur !

http://www.flightglobal.com/articles/2011/04/03/355083/gulfstream-g650-test-aircraft-crashes-on-takeoff-killing-four.html

JPRS

Poncho (Admin)
Whisky Charlie

Re: Crash G650 essai à Roswell (2 avril 2011)

Message par Poncho (Admin) le Mar 5 Avr 2011 - 10:08

Bonjour à tous

Plus de détails

A priori le saumon d'aile droite à toucher le sol en phase de décollage

La suite ici

http://www.aviationweek.com/aw/generic/story.jsp?id=news/awx/2011/04/04/awx_04_04_2011_p0-306226.xml&headline=G650%20Wingtip%20Hit%20Ground%20Before%20Crash%20&channel=busav



he right wingtip of a Gulfstream G650 struck the ground on takeoff before the aircraft crashed April 2 at Roswell Airport in New Mexico, killing all four people aboard, aviation officials say. The National Transportation Safety Board (NTSB) arrived at Roswell on the evening of April 2 to launch the investigation, which also involves Gulfstream, Parker Aerospace, Rolls-Royce and NTSB’s German counterpart, the BFU.

According to NTSB, the aircraft, N652GD, crashed on the runway during takeoff at about 9:30 a.m. MDT. The landing gear collapsed, and the aircraft slid along the ground, coming to rest about 200 ft. from the base of an air traffic control tower.

Investigators found wingtip scrape marks that began about 5,000 ft. from the end of the runway and ran about 3,000-ft. long. “Witnesses close to the scene saw the airplane sliding on the ground with sparks and smoke and subsequent full involvement with fire while it was still moving,” NTSB says.

The airport rescue and firefighting team responded quickly, the safety board adds, and fought the fire for more than 15 min. The fire destroyed the airplane.

NTSB described the weather at the time as clear with good visibility. Wind was 15 kt. directly from the left side of the plane, the safety board adds.

The aircraft had been conducting a series of takeoffs and landings in apparent braking tests prior to the accident, says FAA spokesman Lynn Lunsford. The aircraft would takeoff, do a teardrop-shaped maneuver and return to the same runway to test the brakes. NTSB, which plans to remain on the scene for several more days, expects to release a preliminary report on its initial findings by April 18, the agency says.

Gulfstream says the four people aboard the aircraft included two pilots and two technicians. The experimental test pilots were Kent Crenshaw, 64, who joined the company in 1997, and Vivan Ragusa, 51, who was with Gulfstream since 2007. David McCollum, 47, and Reece Ollenburg, 48, were the technicians aboard the aircraft. They had been with Gulfstream since 2006 and 2009, respectively.

“Our sorrow from the loss of these four great men is very deep,” Jay Johnson, chairman and CEO of Gulfstream parent General Dynamics, said April 4. Johnson adds he is confident that “the cause of this terrible tragedy will be determined.”

The accident occurred as Gulfstream was in the final stages of certification of the aircraft, the flagship of the Gulfstream fleet. Gulfstream was predicting certification and deliveries of about the first dozen this year.

“We look forward to continuing the rigorous testing required to achieve flight certification of the aircraft,” Johnson says, adding, “The G650 will take its place atop the long line of safe, reliable, high-performance business jets on which Gulfstream has built its superb reputation.”

Johnson’s remarks come as Wall Street analysts responded with mixed reaction to the news of the accident. “We expect a meaningful negative reaction to shares, at least in the short term,” says Robert Spingarn of Credit Suisse. “Based on the limited information here, there is a huge range of outcomes.” Spingarn adds there is no way to predict the resulting delay to the program.

“Given the G650 program was within 2-3 months of completing a multiyear-long certification process, if the NTSB rules out design flaws (which most likely would have shown up earlier), then what’s left in testing may be able to proceed with the other aircraft,” says Morgan Stanley’s Heidi Wood. “If the answers are murkier, then Gulfstream may be forced to park the G650 fleet until the right assurances can be met.”

Wood added that until further information is known, Morgan Stanley was maintaining its projections of 12 deliveries this year, given that Gulfstream had completed 1,500 of the planned 2,200 hr. for certification.

“Despite a tragic, serious accident, the G650 likely proceeds with potential delay but no change in our view about the underlying business jet demand,” Wood says. “It’s likely the G650 team will work with steelier resolve than ever before and our assessment of the G650 as Gulfstream’s crown jewel and a contributor to significant earnings growth is undeterred.”




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Poncho (Admin)
Whisky Charlie

Re: Crash G650 essai à Roswell (2 avril 2011)

Message par Poncho (Admin) le Mer 6 Avr 2011 - 9:11

Bonjour à tous

Une petite mise à jour

http://www.flightglobal.com/articles/2011/04/06/355219/g650-was-at-high-angle-of-attack-prior-to-accident.html

A priori le G650 avait une incidence élevée dans cette phase


The Gulfstream G650 involved in the fatal crash that killed four company employees on 2 April was at a high angle of attack just before its right wingtip made contact with the runway, say those directly familiar with events of the accident.
The US National Transportation Safety Board (NTSB) says the wind was 15kts "directly from the left side of the aircraft" when the aircraft began its takeoff roll on Runway 21 at approximately 09:30 local time at Roswell International Air Center Airport in New Mexico.
Wingtip scrape marks appear on runway 21 roughly 1520m (5,000ft) before the end of the 3,960m (13,000ft) runway, which "lead toward the final resting spot approximately 3000 feet from the first marks on the runway," says the NTSB.
Witnesses near the scene say they saw the G650's landing gear collapse followed by "sliding on the ground with sparks and smoke and subsequent full involvement with fire while it was still moving," says the NTSB.
The aircraft then "came to rest upright and fully involved in flames approximately 61m (200 ft) from the base of the airport control tower".
Airport rescue and fire fighting teams responded quickly to the fire, which they fought for 15min after their arrival.
S/N 6002, registered N652GD, the second of five test aircraft validating the new large-cabin ultra-long range jet , had been out conducting 2.5h of take-off performance and braking evaluations prior to the accident, taking off on runway 21 with teardrop turns to downwind landings on runway 3 prior to the accident.

© NTSB
Participating along with the NTSB, is German safety investigator BFU, as the twin Rolls-Royce Deutschland BR700-725A1-12 engines are manufactured in Germany. Additionally, engine-maker Rolls-Royce and Parker Aerospace, which supplies the aircraft's fly-by-wire flight control system, are also party to the investigation along with Gulfstream.
Gulfstream, which has not said if it expects any impact to its 2011 US Federal Aviation Administration and European Aviation Safety Agency certification, and planned deliveries in 2012, has halted all test operations on its four remaining test aircraft, under its own volition.
"I am confident that as Gulfstream assists aviation authorities in the accident investigation, the cause of this terrible tragedy will be determined," says Jay Johnson, who serves as General Dynamics CEO, parent company of Gulfstream Aerospace. "We look forward to continuing the rigorous testing required to achieve flight certification of the aircraft.


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Beochien
Whisky Charlie

Re: Crash G650 essai à Roswell (2 avril 2011)

Message par Beochien le Ven 8 Avr 2011 - 21:00

Bonsoir !

Je ramène ce post ici !

Bonjour !

le Gulfstream 650 d'essais au tapis !
4 victimes !

C'étaient des essais (Simulation) de panne moteur au décollage qui ont mal tourné !

----------- De Jon Ostrower, Flightglobal, le lien ----------------

http://www.flightglobal.com/blogs/flightblogger/2011/04/accident-update-g650-was-simul.html

JPRS

Poncho (Admin)
Whisky Charlie

Re: Crash G650 essai à Roswell (2 avril 2011)

Message par Poncho (Admin) le Ven 8 Avr 2011 - 22:20

Merci Wink




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Poncho (Admin)
Whisky Charlie

Re: Crash G650 essai à Roswell (2 avril 2011)

Message par Poncho (Admin) le Mer 4 Mai 2011 - 9:49

Bonjour à tous

Du nouveau (mais pas très substantiel pour le moment)

http://www.ainonline.com/news/single-news-page/article/investigation-continues-into-g650-crash-29401/?no_cache=1


The investigation continues into last month’s fatal crash of a Gulfstream G650 during a test flight at Roswell, N.M., and it may be more than a year before the cause of the accident is determined, according to the NTSB. Tom Latson, the NTSB investigator in charge of the accident, told AIN the Board will be conducting “a thorough investigation” and confirmed that the aircraft was equipped with a telemetry data downlink. That could potentially provide the investigators with a trove of additional clues, beyond those from the twinjet’s CVR and FDR. Aside from Gulfstream, other parties to the investigation include the FAA, Parker Aerospace (manufacturer of the aircraft’s fly-by-wire flight control system) Rolls-Royce Engines and the German Accident Investigation Bureau (as the 16,100-pound-thrust BR725A1-12 engines on the aircraft were manufactured in Germany).
In its preliminary report released four days after the April 2 crash, the NTSB said the aircraft was performing a takeoff with a simulated engine failure to determine takeoff distance requirements at minimum flap setting. The G650, S/N 6002, registered as N652GD took off at approximately 9:30 a.m. from the main Runway 21 at Roswell International Air Center Airport in Roswell, N.M. in clear weather with a 15-knotcrosswind from the left.
“Immediately after takeoff, the right wing struck the ground,” said FAA spokesman Lynn Lunsford, adding that the landing gear collapsed after the jet hit the ground. The first wingtip scrape marks were found approximately 5,300 feet from the start of of the 13,000-foot runway, between Taxiways Delta and Echo. According to witnesses, the aircraft slid across the ground, issuing sparks and smoke, and caught fire while it was still moving, leaving scorched grass in its wake.
During its slide of nearly 4,000 feet, the jet struck several taxiway signs and lights as it crossed Taxiway Bravo and narrowly missed a line of out-of-service jetliners parked on the airport’s disused Runway 30. It then crossed the tower access road before coming to rest approximately 230 feet from the base of the control tower, noted Brian Powell, a division chief at the airport’s rescue and firefighting department. “It was just a fireball going toward the tower,” said Powell.
It took the airport fire and rescue crew more than 15 minutes to extinguish the blaze, which destroyed the aircraft’s fuselage. Killed in the crash were test pilots Kent Crenshaw and Vivan Ragusa and technical specialists David McCollum and Reece Ollenburg.

Le fait notable : le feu qui semble s'être vite déclaré au début de la glissade musclée et le temps nécessaire pour le maîtriser.

Bonne journée


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Poncho (Admin)
Whisky Charlie

Re: Crash G650 essai à Roswell (2 avril 2011)

Message par Poncho (Admin) le Ven 12 Oct 2012 - 9:42

je n'ai pas encore pris le temps de lire le rapport, mais voilà ce qui ressort dans la presse

Ce que je comprends, Gulfstream m'a pas été très performant dans l'analyse de deux décrochages précédent et avait le pression pour obtenir les perfos demandée
Mais le phénomène découvert lors de ce crash : décrochage d'une aile dans l'effet de sol, n'a jamais été pris en compte par les avionneurs parce qu'il ne le pensais pas possible...
Malheureusement, il a fallu perdre 4 vie pour le découvrir.
A noter le gros boulot de Gulstream pour compendre le phénomène après coup
C'est aussi ça l'aviation

Est ce que j'ai bien compris ?

http://www.aviationweek.com/Article.aspx?id=/article-xml/avd_10_11_2012_p05-01-505411.xml&p=1


The NTSB is asking the FAA to inform domestic and foreign airframers “about the circumstances of this accident,” and to advise them to consider the possibility that an aircraft’s maximum lift coefficient in ground effect could be, in contrast to common belief and practice, lower than its maximum lift coefficient at altitude, a finding made by Gulfstream in its post-crash analysis.

The board also is asking the FAA to work with the FTSC to issue updated operating flight test guidance to manufacturers, based on the report, and develop flight test safety guidelines based on best practices in aviation safety management.

Only two recommendations were addressed to Gulfstream, one of which is to commission an audit by qualified safety experts before its next flight test campaign is launched, focusing on the weaknesses brought out in the NTSB report.

“We recognize the safety action they took [after] the accident,” says Deborah Hersman, NTSB chairman.


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c.foussa
Whisky Quebec

Re: Crash G650 essai à Roswell (2 avril 2011)

Message par c.foussa le Mar 5 Jan 2016 - 19:53

L’accident est survenu au cours d’un vol d’essai, décollage avec panne d’un moteur, l’aile droite décroche très proche du sol, heurte le sol, l’avion s’enflamme et est détruit.

- le constructeur a surestimé l’effet de sol dans ses calculs de performance : si l’effet de sol augmente la portance et diminue la trainée, l’incidence de décrochage diminue un peu. Le constructeur a bien pris en compte l’augmentation de portance mais a surestimé l’assiette de décrochage, mettant le seuil de déclenchement du vibreur de manche et l’indication d’assiette limite à des valeurs supérieures à la réalité aérodynamique. 2 incidents similaires avaient déjà eu lieu sans destruction de l’avion, le NTSB considère qu’une analyse aérodynamique poussée aurait permis la correction du problème : l’avion a décroché avant l’incidence de décrochage mal calculée par le constructeur.

- au cours des essais, il a été noté que l’avion dépassait sensiblement V2 prévu au décollage. V2 permet le meilleur taux de montée en panne moteur, voler au-dessus de V2 réduit ce taux et diminue la pente qui permet de passer au-dessus d’obstacles, allongeant d’autant la distance pour atteindre une altitude initiale. Mais le constructeur voulait assurer la performance « vendue » pour atteindre 6000 ft et un décollage sur une longueur de piste courte. Il leur fallait donc diminuer V2 pour respecter leur performance de vendeur. Ils ont donc diminué V2 en modifiant l’assiette de décollage. Une étude aérodynamique approfondie aurait indiqué que cette technique était insuffisante et inefficace. Leur nouvelle V2 était aérodynamiquement trop basse et irréaliste


- pression temporelle pour certifier cet avion au calendrier prévu, des déficiences dans l’analyse poussée des 2 problèmes aérodynamiques rencontrés, une analyse insuffisante des risques associés .

J'essaye de retrouver l'info du NTSB que j'ai synthétisée et traduite.

Poncho (Admin)
Whisky Charlie

Re: Crash G650 essai à Roswell (2 avril 2011)

Message par Poncho (Admin) le Mar 5 Jan 2016 - 21:37

Merci
Je crois de mémoire que Gulfstream n'a pas chercher à éluder ses résponsabilités


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Re: Crash G650 essai à Roswell (2 avril 2011)

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