par Beochien Sam 14 Déc 2019 - 13:50
Toujours ces histoires d'évacuation de la foudre sur les Ailes de B787, et ... la subséquente protection des réservoirs d'aile ...
Boeing semble avoir retiré une grande partie des sécurités, avec des infos et un timing douteux et un appel "gagné, ou du moins entendu" vs la FAA, maintenant le PB refait surface ...
Evidemment, dans l'ambiance actuelle
Bon, les ailes du B787, ont des PB de poids et de coût, depuis le début ...Donc retirer du treillis de cuivre était tentant, je crois qu'on en a parlé.
Simple Flying, bien documenté pour une foi, reprend le débat, lire aussi le Seattle Times, Dominic Gates, avec des croquis à ne pas manquer
(Images du ST difficiles à copier, désolé) Si qq'un y arrive, merci d'avance.Question ???
Quelle techno et précautions, applique Airbus sur le A350 ??
Et Bombardier/Airbus, sur le A220 ??
Et Boeing sur l'aile du B77X ?
Des risques peut être sur estimés, à la sortie du B787 ?https://www.seattletimes.com/business/boeing-aerospace/faa-engineers-objected-to-boeings-removal-of-some-787-lightning-protection-measures/
https://simpleflying.com/787-dreamliner-lightning-safety/
https://www.aerotime.aero/rytis.beresnevicius/24324-boeing-787-lightning-protection-faa-objection
http://impactpub.com.au/micebtn/85-news/btn-news/25776-max-inquiry-now-considers-787-changes
Un résumé ...
While global attention is focused on the Boeing 737 MAX and its eventual return to the skies, US Department of Justice interest now includes other aspects of the plane maker's operations, including wings on the B787.
This week, a House Committee was told Federal Aviation Administration (FAA) managers ignored their own technical advisors' concerns and approved the removal of a feature of Boeing's 787 wing that was designed to protect it in the event of a lightning strike.
Boeing originally had special measures to protect the wing fuel tank on the largely-composite 787. It sealed each metal fastener in the wing with an insulating cap and embedded copper foil in strips across the carbon wing skin to disperse the current from any lightning strike.
About 2014, however, the plane maker stopped adding the insulating fastener caps and later dropped the copper foil. The wing surface of 787s now lacks both protections.
The FAA initially rejected the removal of the foil from the wing, saying Boeing had not shown that the ignition of fuel tank vapour by a lightning strike was “extremely improbable,” - defined as likely to occur no more than three times in a billion flight hours.
But by then about 40 sets of wings had been built without the foil and Boeing appealed the ruling. FAA managers reversed their decision a week later.
In June, FAA safety engineer Thomas Thorson, concerned that his agency was hurriedly approving Boeing’s desired changes, formally objected.
“I do not agree that delivery schedules should influence our safety decisions and areas of safety critical findings, nor is this consistent with our safety principles,” Thorson wrote, adding the agency’s technical experts had discovered errors in the way Boeing summed up the various risks of the lightning protection features and that with the removal of the foil “the fuel tank ignition threat … cannot be shown extremely improbable”.
Thorson estimated that if the methodology was corrected, the ignition risk “would be classified as potentially unsafe”.