Nick,
what about the old OH-58s and UH-1s (plus a Cobra or 2?) and the ex military fixed wing warbirds/jets? Don't they have 'experimental' on them? Is that not similar to the system we have?

YOY didn't Westland proceed with the proposed P600, a civvie version of the Lynx that I saw pictured in John Fay's book? Mind you, I suspect that if they had we would eventually see the same situation as with the Gazelle - the CofA versions costing twice as much as the Permit aircraft for what feels like the same thing.

There's a big difference between the UK Permit system, and the US Experimental system. Whilst both are sub-ICAO and national-only, how they are treated are quite different.

Under the UK system, the applicant is "invited" to discuss with CAA (or for smaller aircraft PFA or BMAA) the level of rigour which is appropriate to that aircraft - so at one end of the scale the older "type-accepted" microlights are pretty much left completely alone once approved and simply need an annual inspection and check-flight, whilst at the other end of the scale your privately owned Hawker Hunter or Gazellicopter, whilst still on a permit is subject to an approved maintenance organisation, pilot training and currency requirements, and so on. There is also a system of "MPD" or Mandatory Permit Directives allowing CAA a degree of control over anything that worries them (which usually seems to involve parts for Spitfires whenever I glance at the MPD book).

Under the US "Experimental" system, the applicant has to provide a basic summary of the size, shape and limitations to the FAA, and is then largely left to their own devices. The only real control FAA has is to ground an aircraft that severely troubles them, and there is no mandatory independent safety assessment.


You can debate endlessly which is the better system (and many do) - personally I do prefer the UK approach so long as it's administered in an enlightened and pragmatic manner. But then again, I live on a small crowded island where it's quite hard to kill yourself in a flying machine without it having some impact on somebody else - not so in the US where it's relatively easy to minimise 3rd party risk.


Probably the most contentious issue in the UK concerning permits is the lack of permission for some types - warbirds in particular - to fly night or IMC, which is prohibited. There's a sound argument that, say, a Hunter is far safer at FL150 or in an airway having punched up in IMC than mucking about low-level in marginal visibility amongst lots of light aircraft flying at half it's speed. I think we'll win that argument with CAA eventually, but it's taking a long time to even keep the blighters at the negotiating table.

G

Genghis,
I agree with your input and add that the US system depends on the signature of the MIDO (Manufacturing Inspection District Office) inspector who is assigned to you. He is empowered with the ability to approve or not, and his guidelines are nearly nil, so it is really based on whim. Furthermore, he is personally responsible with the outcome of his decision, so that there is little incentive to approve, and lots of reason why a career civil servant would say NO.

The crash of an F-86 into an ice cream parlor a few decades back propelled a major reduction in restricted certificates, and those spectacular crashes of the water bombers last year did not help.

One thing that troubles me about the FAA approach is not so much the variation in working standards of the MIDO (we know here that your relationship with your DLS - CAA Design Liaison Surveyor, can make or break a project, or even a company) is that all they are really checking is build/maintenance quality.

In my mind, airworthiness is a much more complex problem than that, and unless some kind of design and operating procedures review takes place in addition to that, there's a serious flaw in the system.

G

If I'm not mistaken the Westland 30 was the Civvy Lynx. Sold a few to the Indians or the Pakistanis but they never used them (cost/availability of spares?). There's one at the helicopter museum in Weston Super Mare. In fact didnt Westland have a 30 for their own corporate use?

Wasnt the WG30 much bigger than the Lynx ?

:E

Externally yes, but the basic powertrain and associated engineering were all based upon the Lynx.

Mind you, the Lynx design was supposed to be based upon the Wessex, which I think lasted for about 3 government-induced design iterations before going completely out of the window and forcing Westlands to effectively design a totally new helicopter.

G

Westland were worried about the 'pile' of 30's lying unloved in India so they have bought out the airframes and the type certificate [?] to ensure that no-one can operate them. They all came to a dealer in he UK about a year ago.

I think there is a technical problem with later operation of the Lynx. As I understand it the airframe is lifed and that life cannot be extended.

The current type remanufacturing activity is along those lines ... throw away the tin box and build in the removable parts on a new manufacture box.

I may stand to be corrected on that but it is along those lines.

LYNX main servo valve seizure
 

:confused: Heared rumours off a British Lynx over London loosing 300 feet during a main servo valve seizure in roll.
Was it the new actuators or the old servos??
:hmm: Also heard that it was the left seater that switch off the appropiate hyd. system???

:confused: Any rumors .....

It was the old pre-mod 793 servos which have since been replaced in this specific aircraft! And yes it was the left hand seat that flipped the hyd 1 switch as the handling pilot had the vulcan death grip on the collective at the time! Thank heavens it was at 1000' and not low level.

As a planky I dunno what you APT guys are talking about but it sounds like a new underwear day.
TF it worked out OK.

Was this recent???

Yep, TF all is well except for the obvious underpant exchange.

It would seem that the landing light switch was avoided. Wel done LHS.

this happened a few months ago and an incident signal was circulated as you would expect. Lets hope that the new actuators don't play up like this set did eh?

:uhoh: A change off underwear would be in order!!

:ok: Nice job of the LHS!!

Did the cyclic actualy move in the direction off the main servo valve seizure in roll?

As fare as I know this is one off the first seizures that the crew actualy lived to tell the story, well done!!!

:ok:

Yes the cyclic did ramp over to the right and the RHS was fighting it for all his life! One flick of the switch and it came back gradually, not an instantaneous affair.

Thanks for the info!!!

PONTCIVVY is it possible to get a copy off the incedent report??

I am always looking for information from the real world to check if the simulation world is doing it correct!! :rolleyes:

Probably a bit late in the day to investigate failure trends now on the Lucas Servo. DARA Almondbank were/are the 4th line service unit and have ALL the overhaul/repair records, going back to serial No1, in their very dusty archive.:O

PE No1, I think, if my memory is correct, that this is the first ever servo valve seizure. Of course, I could be wrong.