Mil Vs Civ Type Certification

[Rotorhead]

Down here in sunny Cape Town we have an operator flying a UH1 carrying paying passengers. What are the differences between miultary and civil helicopter certification, in this case the UH1 and Bell 205?

Does this happen anywhere else in the world - civil operators using ex military machines for flipping?

Ta.

[Genghis the Engineer]

I can't speak with any authority about the rest of the world, but here in the UK...

(1) Civil certification is primarily against demonstration of compliance with a standard. Military certification is against demonstration of capability, with compliance with the standard being secondary.

(2) Military and civil standards are different, usually based upon very different premises (i.e. operational capability versus pure safety).

(3) Here in the UK many ex-mil types are flying by issue of a document called a "permit to fly" which allows private use only. Commercial use of an aircraft requires a CofA, for which the aircraft must have originally been issued with a civil CofA, or at-least be identical to one which was. Any businesses in this area are providing operating facilities for private owners, not operating the types commercially.


To the best of my knowledge, there's no particular philosophical difference between fixed and rotary winged aircraft in this respect.

Hope this helps,

G

[VP959]

With the greatest of respect Genghis, and knowing your background somewhat (as you know mine I suspect), things have now moved on in the military certification world. Nowadays, 00-970 is pretty much exactly the same as the equivalent civil spec, and must be complied with in the same way before a MAR will be issued.

Once upon a time things were different. with the situation being approximately as you described, but liability and the duty of care has caught up with the military world in the UK now.

[Cyclic Hotline]

The UH-1 was built to a military operations specification whereas the Bell 205 was built to conform to an FAA Type Certificate Data Sheet (TCDS) as a standard category transport helicopter.

The principle difference is that one was built specifically to an FAA specification and the other was not. This does not imply that the UH-1 is not a capable and airworthy helicopter, simply that it was not designed and manufactured to meet any FAA criteria.

As the UH-1 helicopters became available under the Surplus system, a considerable number of them were purchased by commercial operators and certified under FAA Restricted Category rules. This certification is based upon the aircraft having previously been operated by the US military and is subject to a number of operational limitations, principal amongst them, that they do not carry passengers.

In order to operate the aircraft under Restricted Category rules, the aircraft must be conformed to a Restricted Category TCDS, which as Bell never produced one, meant that the operator had to create one and obtain FAA approval for it. The approval is based upon the military manuals and operating limitations, and each aircraft to be conformed to the TCDS must be individually inspected and certified. The FAA interpretation of Restricted Category defines that the aircraft does not enjoy the same level of airworthiness certification that the commercial variants do, and as such must be operated with a variety of limitations to protect the public.

The similarities between the UH-1 and the 205 are many. The differences between the UH-1 and the 205 are also many. The biggest issue that has caused havoc in the business, was individuals that attempted (in many case, succssefully) to pass a UH-1 of as a commercial variant.

One business came very close to getting a Type Certificate that would allow the UH-1 to be certified as a commercial aircraft. In doing so they would have to provide a certification package to meet all current FAA certification requirements. Essentially the aircraft would then conform in the identical manner to the airworthiness standards of the 205.

There is nothing to stop an ex-military aircraft from being conformed to a commercial TC, so long as the means is available. The Bell helicopters do not currently have this means open to them, but for years people practiced this illegally (by putting a commercial data plate on a modified military machine). A few years ago a number of operators ended up with their aircraft grounded and essentially rendered worthless, when the FAA cracked down on this. As the aircraft neither conformed to the commercial Bell TCDS, nor any Restricted Category TC, they were rendered non-flyable when their Airworthiness Certificate was revoked. Interestingly Transport Canada did not do the same-thing, but advised operators that their aircraft may be unable to be conformed should they ever try to export them!

There exists a copy of an engineering report that Bell provided to the US Government that details the basis of all engineering work that was accomplished on the UH-1. It is prefaced that it is essentially the same data as exists for the commercial variants. The vast majority of parts are identical (by Part Number) between the commercial and military models. Much of this can be witnessed by looking at the history of the various models and noting that the same failures and problems occurred amongst them all. The AD list for these products shows similar traits.

One of the problems concerning the ex-military Bell equipment is that the Government procured replacemant parts under the lowest bidder system. As a result there are a lot of sub-standard parts on the market, that have nothing to do with Bell Helicopter and everything to do with safety! In the mid 90's the government realised that this was a ridiculous position to be in, and changed their procurement system. It does not however protect teh operator of an aircraft from existing installed parts.

Basically a UH-1 is not a 205, no matter what anyone claims.

[Genghis the Engineer]

VP, I had no intention of suggestion that the military anywhere release substandard aircraft, but the processes are still very different.

In the civil world, compliance with the standard is the be-all and end-all. If it happens to be a useless piece of junk that doesn't do the job, that's no concern of the authority.

In the military world, safety is a given and standards are high. Strict compliance with the standard however is not an absolute. Military authorities (Boscombe, Edwards, etc.) routinely decide to disregard non-compliance with the relevant standard. BUT, they do not if they can help it consciously release an aircraft that they consider either unsafe or unable to do the required job - even if it does meet the spec.

The upshot is that starting from the same place you'll end up often with substantially different aircraft to meet military and civil requirements. So, unsurprisingly, there can be huge difficulties in getting an aircraft that is already complete to "jump the gap".

G

[Shawn Coyle]

Cyclic Hotline:
Excellent summary of the situation. One of the real problems is that parts were made by/for the US Army without the necessary civil traceability.
Rotorhead:
You might ask the South African CAA to see if they can show the civil Type Certificate Data Sheet for the helicopter. You might also ask what Certificate of Airworthiness this is based on, and if you know the operator's insurance company, you might ask them what they know of the situation.

[idle stop]

Here in UK we have quite a few aircraft that are Contractor Owned and Military Registered. The aircraft are leased to the military by a commercial company and the aircraft are maintained by the company according to civil aviation regulations. However, since they are on the military register (by agreement of the MoD accepting the civil aircraft standard and maintenance procedures) the aircraft are flown according to military regulations.
One of the ideas of doing this is to avoid precisely the problem that Shawn alludes to; in so doing it means that the parts audit trail is preserved and all servicing paperwork is in place to put the aircraft back on a civil register if required. This enhances the residual value of the aircraft, making COMR a realistic proposition to both Contractor and MoD.
As regards certification, the military authority has to accept the civil standard as regards certification of the aircraft and installed equipment, although it may overlay different standards as to usage.
To give an example, a cockpit modified to meet military standards as NVG compatible must meet civil certification standards 'as is' for day or night VFR/IFR. The military authority may then apply its regulations as to when and how the aircraft may be used for NVG operations. (Before some purist reminds me: yes, I know that some limited civil NVG use is approved in UK!)
As regards the differences in civ/mil standards themselves, in general they are not a world away from each other, and the processes are very similar (unsurprising since most civil and military TPs and FTEs have 'been to the same schools') but where philosophy does differ is in the acceptability of risk. Thus the probability of failure in civil certification may (word used advisedly!) be to a higher standard than is demanded for a military aircraft.

[Rotorhead]

Thanks Gents/Ladies?

When in doubt ask an expert - ta for the time and effort.