Crash Safety g Loads
Crash Safety g Loads
(OP)
Hi all,
I have a major problem on defining g loads for ceash safety qualification tests. RTCA DO 160E Chapter 7 Defines 20g for 11-20 ms, while MIL-STD-810F Method 516.5 chapter 4.5.6.1 defines 40g's for 15-23 ms's.
IMHO, 40g is not a logical test level for aircraft other than fighters, -which may crash with very high speeds- but I need a proof, an opinion is not enough to convince qualification guys. Does anyone have any experience on these standards?
I have a major problem on defining g loads for ceash safety qualification tests. RTCA DO 160E Chapter 7 Defines 20g for 11-20 ms, while MIL-STD-810F Method 516.5 chapter 4.5.6.1 defines 40g's for 15-23 ms's.
IMHO, 40g is not a logical test level for aircraft other than fighters, -which may crash with very high speeds- but I need a proof, an opinion is not enough to convince qualification guys. Does anyone have any experience on these standards?





RE: Crash Safety g Loads
Your hope lies in what the equipment is used for; who cares if a passenger entertainment system works after a crash, but it is critical for cockpit voice recorders to survive.
RE: Crash Safety g Loads
i think der8110 has a good point about the function of the box, but i think the problems mostly arise from holding the box down (then the FARs make a distinction between in-cabin equipment (that can hurt pax) and out-of-cabin equipment.
RE: Crash Safety g Loads
From the incident report http:
we get this:
Seats designed for 16g collapsed and some broke away in an accident with a probable peak g loading of 22 -28g (p106). Within the physiological limits of the passenger. Seats collapsed, and all but 14 of the passengers sustained injury to their legs to the extent that they could not contribute significantly to their egress (p48).
The impact speed was 90 knots.
So yes, 40g is a pretty good number to go for.
RE: Crash Safety g Loads
RE: Crash Safety g Loads
Since when to do the test guys get to decide what the specification is? They are not allowed to be "convinced." The specification is what they are supposed to do. Just what is your specification?
Surely, you didn't get all the way to qual BEFORE figuring what the design requirements are? What does your contract or specification say?
TTFN
RE: Crash Safety g Loads
RE: Crash Safety g Loads
His question then doesn't make any sense, because the requirement is the requirement
TTFN
RE: Crash Safety g Loads
My company is about to design a new aircraft, which will be certified according to EASA CS 23. CS 23 directives about crash safety are 18g's in each directions. But also, there is a second qualification authority. Requirements of this authority is forming nowadays, including environmental qualification requirements.
Environmental qualification of this aircraft will be customized with requirements from RTCA DO 160E & MIL STD 810F. We are now in contract & specification negotiation phase. That's why I can't simply open the specification and do what it says: I'm a member of specification writing group.
Of course, standards are written by the grizzliest guys of aviation industry, I'm not questioning their experiences. But there are two standards which say different things. If I chose RTCA-DO, I have to find a good proof for qualification group. If I chose MIL, which has higher requirements, I have to have a proof for my boss. That's why I'm looking for someone, which experienced a similar situation.