Archive for the 'FAA' Category

Boeing 787 Dreamliner: Composite Airframe May Be Unsafe?

A former employee of Boeing who has been laid off last year claims that the new carbon-composite airframe of the upcoming Boeing 787 Dreamliner may be unsafe. According to ATW News, Vince Weldon who had worked for Boeing for 46 years claims in an interview with journalist Dan Rather that he was fired in 2006 because he pointed out safety glitches in relation to this new breakthrough technology to be used widely in the construction of the Dreamliner (composite is to replace aluminium in the bodyframe of the airliner).

The new Dreamliner – which was revealed a little more than two months ago – is to have a body fully built from composite materials, which guarantee weight reduction (thus increased fuel efficiency and less environmental harm), as well as the possibility of more humidity in the passenger cabin, which would reduce the effects of flying on the human body. At the time when he was laid off, he was working for the Phantom Works technology centre of Boeing, developing the new composite plastic materials for the new aircraft. Boeing officially claims they had to fire him as he had assaulted his bosses several times.

Boeing 787 Dreamliner Composite Fuselage - by Boeing

The former employee claims that the new structure carries several risks, which are known to Boeing as well, who try to hide it as they wish to begin manufacturing and delivering the aircraft as soon as possible. Boeing has more than 700 firm orders for the aircraft already, the first one due for delivery to ANA in MAY2008. The former engineer says he can support his arguments with archived internal e-mails between Boeing colleagues, while Boeing announced that they were earlier faced with such problems, which have been solved by nowThese risks according to Mr. Weldon would be:

 

  • the brittle carbon-composite compounds based airframe would break much easier than the traditional, more flexible aluminium aircraft body in an emergency landing for example (more likely to shatter on any impact actually),
  • if ignited and catching fire, it would omit poisonous and toxic gases and chemicals while burning,
  • the fuselage is less resistant to lightnings while flying,
  • any damages are harder to see and visually locate.

According to him these risks would reduce the chance of survival in case of an accident involving any of the above described situations. Just to remember: last week a McDonnel Douglas airplane has broken in two and caught fire during an (emergency) landing in Thailand, claiming 88 deaths and leaving 42 survivors who could escape the burning airplane – so such a situation can happen with a traditionally built aluminium aircraft as well unfortunately, but he says the risk of such a situation largely increases by the usage of composite materials.

The B787 is currently undergoing the tests of the Federal Aviation Administration (FAA), which will allow the production later on if all tests are passed, and therefore justify the worries expressed above, or reject them. The first crash-tests (drop-tests) brought good results for the new aircraft, but most of the testing (and all flight tests) are still to take place in a reduced, speeded up schedule of about 6 months – much shorter than previous airliner programs (see our earlier post about the delay of the first flight).

At first one could even think that these arguments may be fueled by Airbus but separately last week Airbus confirmed to ATWOnline that it has ditched the aluminum frame for a composite frame on the A350 XWB. The move came after key customers ILFC and Emirates expressed concerns about maintenance on an aluminum structure. The original plan involved composite panels on an aluminium frame, but now Airbus has voted to go for an all-composite structure, similar to Boeing’s 787 Dreamliner, which suggests that the technology must be safe enough to be rolled out to production.

An Airbus spokesperson said last week that the decision was taken for “simplification of maintenance.” (Mr. Weldon argues that maintenance of composite structures becomes more complicated due to some damages remaining invisible…) The company expects to complete design refinement by year end with first delivery in late 2013 (some 5 years behind the planned first delivery of the 787).

So what can we do? I think the best is to wait for the test results of the 787, which will be the first aircraft with a composite airframe, but the doubt will now be there in some people’s minds for sure. I’m still excited to fly the Dreamliner and am looking forward to a better, more humanly onboard environment with the different pressure and humidity, that would never be possible in an aluminium framed aircraft and of course hope that such risks mentioned above will never be tested in real life…

by balint01

Advertisements

Boeing Released Warning AD On 737 NG Bolt Folowing Air China Plane Fire

Following the accident of China Airlines on 20 August caused by a loose bolt moving away from its place, piercing through the fuel tank resulting fuel leakage that ignited and exploded only a few moments later passengers could all leave the aicraft, FAA and Boeing released an Emergency Airworthyness Directive (AD) to all owners and operators of Boeing 737 600s, 700s, 800s and 900s (737 NG – New Generation aircrafts) – there are more than 780 of the affected planes registered to US airlines and another 1,500 flying elsewhere around the world.

In the background information of the AD we can read “We have received reports of parts of the main slat track downstop assembly coming off the main slat track.” Not only the China Airlines case is mentioned. There are references to more cases.

The directive says all owners and operators are responsible “for having the actions required by this AD performed within the compliance times specified, unless the actions have already been done.” The airlines and operators have 24 days for checking all involved aircrafts. It is not a major check though. Malev for example will have to spend a total of only 8 man hours on checking all of their 18 737 NG aircrafts.

The way this check needs to be performed is described in a surprisingly detailed way. E.g: “An intensive examination of a specific item, installation, or assembly to detect damage, failure, or irregularity. Available lighting is normally supplemented with a direct source of good lighting at an intensity deemed appropriate. Inspection aids such as mirror, magnifying lenses, etc., may be necessary. Surface cleaning and elaborate procedures may be required.”

Explanation how the slat bolt needs to be checked

Such ADs released by FAA are officially mandatory for aircraft operators in the USA. Airliner operators all over the world usually consider all those warnings mandatory, which are released by the national Air Safety Authorities of the plane manufacturer’s state. In this particular case as Boeing is a US manufacturer, the FAA warning will be taken over as mandatory by all operators of 737 NG’s, and in general foreign aviation safety authorities usually follow FAA recommendations. On top of the FAA release, Boeing has issued its own warning to all NG operators directly, on 25AUG as well.

For detailed information see FAA’s website.

By Szafi

Blog calendar

July 2019
M T W T F S S
« Apr    
1234567
891011121314
15161718192021
22232425262728
293031  

Archives

Advertisements