ACTUALITE Aéronautique : Suivi et commentaire de l\'actualité aéronautique
A Qatar Airways Boeing 787-800, registration A7-BCK performing flight QR-1360 from Johannesburg (South Africa) to Doha (Qatar), was climbing out of Johannesburg's runway 03L when the nose gear doors did not close prompting the crew to stop the climb at FL120 and enter a hold to work the related checklists without success. The aircraft dumped fuel and returned to Johannesburg for a safe landing on runway 03L about 65 minutes after departure.
The flight was postponed to the next day and is anticipated to depart on May 8th at 10:00L with a delay of 18:45 hours
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GE asserts that the GEnx ice-crystal encounters occurred in conditions different from certification requirements. Strong convective weather can lift high concentrations of moisture to high altitudes, where it can freeze into ice crystals, Boeing explained. Such convective weather systems can cover a diameter of 350 nm.
Engineers now understand the principles of how ice crystals can create in-engine icing, sometimes inside the core. They bounce off freezing surfaces near the front of the engine and enter the core. Then, in the compressor, ice crystals melt on vane surfaces, creating a film of water. Particles keep impinging on the wet vane, cooling it to the point at which ice can form. Eventually, the ice accumulation breaks off and can cause various engine malfunctions, including flameout.
The NTSB also discovered that other federal agencies were aware that a nail-penetration test would not conclusively ensure that a failure in one of lithium ion’s cells would not cause a chain reaction in other cells, called a thermal runaway.
The FAA instead relied exclusively on Boeing’s expertise to approve the lithium ion battery. As a result, the FAA should consult a panel of independent experts when considering how to determine the safety of new technologies, the NTSB says.
The FAA also approved Boeing’s solution to the battery crisis in 2013. Rather than switch to a new battery design, the FAA lifted the 787 grounding order after Boeing installed a kit aimed at preventing a thermal runaway event from causing damage to the rest of the aircraft. The battery cells are spaced farther apart and are contained within a stainless steel box with a vent used to channel any escaping fumes directly out of the aircraft.
But the NTSB also urges the FAA to “re-evaluate internal short circuit risk for lithium ion batteries now in-service”.
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par pascal83 Jeu 24 Avr 2014 - 18:07Photo: Cheers to All Nippon Airways for taking the 150th delivery of the #Boeing 787 #Dreamliner! #avgeek pic.twitter.com/YXd4FWUe6N
— Boeing Airplanes (@BoeingAirplanes) 4 Juin 2014
Description of Relief Sought: Petitioner seeks time-limited relief from 14 CFR 25.1305(c)(5) at amendment 25-120 in support of Certification Plan 15053, for the power plant ice protection system indication requirement on Boeing Model 787-8 and 787-9 airplanes equipped with GEnx-1B/B175 engines.
