military fatigue assessment & washout

[nzhills]

Hi,

I originally posted this in the Tech forum, but was advised that this would be the right place for this quesiton.

1. How does the military go about estimating the fatigue life / usage of their machines, be they aircraft or choppers? Is there a US military procedure where you put in the weight carried, flight path loading, (i.e. is it just a standard 1.1g - 1.2g flight or did it have a hard landing) / environment, (was the flight low down in rough air)? Then from this you can work out how much airframe life was used? I imagine for the choppers the engines and transmissions would have hard times/lives, but would how would the airframe usage be accounted for? Would the modern military choppers, i.e. NH90, be any different?

2. Does anyone know the washout applied to the wing of the F/A-18A and was it changed as this airframe progressed through to the E/A-18G?

Regards
Mark

[NutLoose]

Bump ;). .........

[Hot 'n' High]

.......... 1. How does the military go about estimating the fatigue life / usage of their machines, be they .....

I'd start somewhere like here https://www.skybrary.aero/index.php/Health_and_Usage_Monitoring_System_(HUMS) :ok:

Seriously, there are such a vast and diverse set of solutions based on the concept of HUMS and variants thereof, all tied into the particular Services, Manufacturers and A/C Types (both F/W and R/W) it's better you start with Google to just get the general idea. There will be as many solutions as there are aircraft types/customers. There is no one answer but the above is a good lead-in with some more links. Civie or Mil, all basically the same but tailored to roles/capabilities clearly.

F-18 washout? Not a scoobie!

Cheers, H 'n' H

[BEagle]

nzhills , this might give you some insight into the UK system: https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/701195/Structural_Integrity_Handbook.pdf

Operating beyond the SOI assumptions can have drastic effects on fatigue life. The ham fisted idiot who decided to do an 'airshow flyby' in a VC10K3 at MTOM, then pulled up into a climb, used about 2 years of normal fatigue life.

[Hot 'n' High]

nzhills , this might give you some insight into the UK system: https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/701195/Structural_Integrity_Handbook.pdf......................

Beags, what on earth has nzhills done to you to deserve the suggestion he/she(?) suffers having to read an RA?????!!!!!!!!! :eek: Or even just a Guidance Document to an RA!!!! That's just cruel!!!!!!!!!

Hope it's better written than some RAs I was trying to use recently in industry. I even had to submit proposed amendments to two of them just so they made sense. It's a bit of a worry when the RAs themselves started getting confused between the Services and Industry in their processes!!! :hmm:

H 'n' H

[heights good]

Choppers are motorbikes and helicopters are aircraft :O

[thunderbird7]

I thought this was a thread about laundering DPM clothing..