Caribou Engine Mount Problems, Can anyone shed any more light?

[Brendan Cowan]

I picked this up from:

http://www.flightglobal.com/articles/2008/01/11/220723/faa-mandates-caribou-checks.html

The operator of the Australian Caribou fleet can only be the RAAF.

Can anyone add anything to this from the RAAF side of the story?

:blink:

BC


FAA mandates Caribou checks
By John Croft

The US Federal Aviation Administration has issued a mandatory airworthiness directive (AD) for US-registered Viking Air DHC-4 and DHC-4A Caribou aircraft. The action, first issued by Transport Canada in November, came after an Australian operator performing a heavy maintenance check on a DHC-4 discovered that both of the upper engine mount bracket assemblies for one engine were cracked, a problem that could result in the engine ripping itself from the aircraft. Inspections of 10 other aircraft in the same fleet exposed five more cracked brackets, according to the FAA.

Within 10 flight hours starting 23 January, the agency is requiring US operators to perform a one-time fluorescent penetrant inspection of the mounts, an inspection both Transport Canada and Viking Air have also required or suggested.

Viking purchased the type certificate for the DHC-4 and six other De Havilland aircraft from Bombardier in February 2006.

In the USA, the AD is in large part directed at Pen Turbo Aviation, the Cape May, New Jersey-based operation that owns 37 of the 47 US-registered Caribou -nearly 80% of the fleet.

Pen Turbo Aviation president R Gobalian says a cursory check of his DHC-4 and DHC-4As has not turned up signs of the problem, although he has not yet performed the FAA-mandated test.

Virtually all of Pen Turbo's Caribou are parked at Cape May Airport in New Jersey awaiting engine make-overs and buyers. The company has a supplemental type certificate to convert the Pratt & Whitney R2000 radial-powered twins to Pratt & Whitney Canada PT6A-67T turboprops.

Gobalian's idea was to sell the conversion to the Australian Air Force, which uses more than a dozen R2000-powered Caribou. Despite the advantages - Gobalian says the $4 million-plus retrofit boosts payload and performance while greatly increasing engine life and reliability - the Australians have not placed an order.

Pen Turbo has completed the conversion of one aircraft and says a second will be under way once a sale is made.

Gobalian tells Flight International that interest in the aircraft is high in countries with little airport infrastructure, including Indonesia, Mozambique and New Guinea. Financing has been the key issue with long distance sales, however. "Who's going to repossess an aircraft on the other side of the world? If it leaves here, it's got to be paid for," he says.

[herkman]

I would doubt if the turbo conversion would use the mounts used on the R2000.

All of the R2000 instalations on the Australian Caribous were second hand, which were sourced from mainly American Airlines aircraft. R2000 engine good as they are, are now close if not 50 years old, and it is unreasonable not to expect failures.

It is unlikely that they will buy the turbo conversion, which if I recall correctly was first offered in the late 60's, but was rejected at that time because the army did not want the logistics of yet another fuel to be staged in remote areas.

Of course things have changed in that area, but the real problem is that the airframe now is too narrow for most army light vehicles.

The aim of the RAAF is to be able to load on pallets that will suit the C17, which really come from the C130 fit, and to be able to be carried right down to the chinook. Even by turning the pallet onto its 88" width, will still not fit in the Caribou.

Be a sad day to see them go, but my understanding is that we are the last airforce to be still operating them.

Regards

Col

[Brendan Cowan]

Hi Col,

I'd have to agree that any further Caribou upgrades or additional airframes are unlikely in the extreme.

Cheers

BC