Crashworthy Fuel Systems

[SASless]

Should Operators be allowed to continue operating aircraft without Crashworthy fuel systems?

The Start (AS-350) figures prominently in Fatal helicopter crashes that were survivable except for the post-crash fire that is caused by Non-Crashworthy Fuel Cells rupturing and spilling fuel.

The Video contains excellent video recordings taken of actual accidents.

[HeliHenri]

NTSB calls for crash-resistant fuel systems in helicopters :

NTSB calls for crash-resistant fuel systems in helicopters | Vertical Magazine - The Pulse of the Helicopter Industry (http://www.verticalmag.com/news/article/NTSBcallsforcrashresistantfuelsystemsinhelicopters)


Around 110 000 $ for a 350 B3/B3e/B4 retrofit !

[Never Fretter]

Its not just the AS350 (as Vertical point out) as the NTSB recommendation was launched after a 206L accident in Texas in Oct 2014.

Europe and Australia have both issued ADs on the Robinson fuel system.

Is their a retrofit for the 206?

A good summary:

Crashworthiness and a Fiery Frisco US HEMS Accident (http://aerossurance.com/helicopters/fuel-fiery-frisco-accident/)

[Spunk]

... and that's why my personal opinion is that the AD for the Robinson is bull****.
First of all I think that the way the bladder tanks in a Robinson are constructed won't be any good during a crash and secondly it should be either all or nothing.

[jeffg]

Presentation on the issue given by the FAA:

http://www.faahelisafety.org/wp-content/uploads/2015/05/FAA-Analysis-of-PCF-and-Rotorcraft-Fatal-Injuries_FAA-Rotorcraft-Conference_Apr-2015_LR.pdf

[SASless]

One area where the Study may have gone wrong is they looked at Manufacture "Date of 2003" and earlier and "After 2003".

It is Certification Date of the Original Aircraft that is important as that sets forth the Standard to which the Aircraft is designed, built, and certified.

A new build Aircraft can still have non-Crash Worthy Fuel systems.

So any statistic that relates to Post Crash Fires and uses Year of Manufacture as a Filter is meaningless.

Or....do I miss something?


Divided the fatal accident data from 2008-2013 into two groups:

(1) Rotorcraft manufactured in 2003 or prior to 2003

(2) Rotorcraft manufactured after 2003

[RVDT]

Lies, damned lies, and statistics" is a phrase describing the persuasive power of numbers, particularly the use of statistics to bolster weak arguments. It is also sometimes colloquially used to doubt statistics used to prove an opponent's point

Mark Twain?

[JohnDixson]

So did I, SAS.

May I add a " but ", that while the discussion topic is Crashworthy Fuel Systems and the referenced report link by Jeffg adds the subject of Crashworthy Seat design, is it a done deal if the OEM adds crashworthy fuel and seats, but does nothing about design crash load/energy absorption factors of the basic airframe and gear?

[212man]

The Video contains excellent video recordings taken of actual accidents

Can't see a link anywhere :confused:

[SASless]

As usual....212man is spot on. Let me find the lost link.



https://vimeo.com/149457398

[widgeon]

Did the 350's they supplied to the Army for basic training in UK have crashworthy fuel systems ? I think they has their own model designation .

designation is AS350BB , tcds shows identical fuel capacity to BA so I guess the answer is no

[Hot and Hi]

it should be either all or nothing
It should be all what?

[jeffg]

I see what you're saying SAS and I think it may be that it's a presentation and some of the info may be clarified by the speakers notes. Just a guess on my part. For example in the bullet point directly above the one you quoted they address your concern

Could analysis by date manufactured be accomplished?
– Yes: Feasible, but provides much less valuable information.
– Even if manufactured after 2003,may still have a certification basis date many years (perhaps decades) prior to 2003

Also if you look at the conclusions on pages 10-13 it's broken down based on compliance or non-compliance with 27.952.

I'm guessing the 2003 break has to do with comparing their data to the Taneja & Wiegmann study released in 2003. Otherwise the 2003 date makes no sense since both CFRs referenced in the report took effect before 2003.

Again all just guesses on my part. I knew the presentation was out there so I thought I would add it to the discussion.

[SASless]

The best way to compare the value of the Crashworthy Systems is to compare them to the Non-Crashworthy systems in the same aircraft when that is possible.

I know commonsense is a rare commodity today once you introduce Bureaucracy into the discussion but all it takes for me is see the spilled fuel flowing across the Car Park with a small fire within the Airframe.....to be followed by the raging fireball that results when the two come together to form the huge fire.

My generation of combat helicopter pilots died in post impact fires until the US Army embraced the notion of crashworthy fuel cells in the UH-1 Huey.

I got to visit the Camp Zama Army Hospital Burn Ward myself and saw first hand the results of such incidents. Fortunately for me it was a short rather mild experience. I got there due to a cockpit fire caused by pressurized hydraulic fluid and anti-aircraft ground fire getting together at a bad place and time.

Although for different reasons, my exposure to a real fire while flying a helicopter made me a convert to the importance of any effort that reduces the chance of a fire.

[HeliRotor]

The Guimbal Cabri G2 has sorted the fuel tank issue very well. The 170L Kevlar-lined tank has been tested to drop 15m full of fuel and with no leak, rip or scuff. I can see no reason why this cant be replicated by other if not all manufactures. All clever stuff.

[homonculus]

Fortunately I spend my time in burns units on the other side, so I agree manufacturers need to do more. But why stop at fuel systems? Interior trims are not always fire retardant. EMS ships often have considerable medical kit that is flammable (electronic devices are checked for flammability but carry on equipment such as cases, blankets are not) and is crew clothing always fire retardant?

Formula 1 has done so much to eliminate not only the risk of fire but also the consequences. Helmet design in helicopters, just to take one example, is light years behind.

Much to do I am afraid

[riff_raff]

Thanks for the slide presentation jeffg. The most interesting point it brought up was the high incidence of head blunt force trauma in the crashes studied. How many of those experiencing this type of injury upon impact were incapacitated enough to prevent them from exiting the aircraft on their own? As someone else suggested added protection for the occupant's head, such as airbags, might be very effective for improving survival rates where there is a PCF.

NTSB A-15-012 would only affect newly constructed rotorcraft. But it would likely require some re-certification effort of older models still in production to meet the current FAR part 29.952, 29.863, etc. Retrofitting the fleet of existing rotorcraft would present some issues. It may not be worth the cost for some older rotorcraft. And it may not even be possible to retrofit the fuel systems of some older rotorcraft to meet the current requirements.