Dave,
Getting back to the topic of Intermeshing rotor desynch's (sorry to keep bringing this up).
NTSB Identification: MIA83FA183 . The docket is stored on NTSB microfiche number 22314.
Accident occurred Thursday, July 14, 1983 at NEAR CLERMONT, FL
Aircraft:KAMAN H-43B, registration: N57996
Injuries: 1 Serious.
The helicopter crashed in an uncontrolled descent from a hover. A witness stated that the helicopter was slowing descending to position a 150 ft line for the ground crew when he observed something separate and the helicopter came down in a vertical descent. Investigation showed that the transmission and rotor assemblies separated in flight. The engine continued to operate after the crash and had to be shut down. The pilot sustained a head injury and does not recall the accident.
The national transportation safety board determines the probable cause(s) of this accident as follows.
Rotor system..separation
Rotor drive system,main Gearbox/transmission..separation
NTSB Identification: SEA93LA105 . The docket is stored on NTSB microfiche number 50380.
Accident occurred Wednesday, May 12, 1993 at ANATONE, WA
Aircraft:KAMAN HH-43F, registration: N846D
Injuries: 1 Fatal.
The converted military helicopter was in a hover lifting an external load of logs when the main rotor pylons separated in flight, resulting in an uncontrolled inverted descent into the ground. On-scene examination revealed that the transmission rotor input gear shaft, Pt/no: K774515-5F, had fractured. Safety board metallurgical examination showed that the fracture was characteristic of fatigue failure, and indicated repetitive high loads. The FAA type-certificate, based on military configuration, lists the approved engine as 1100 shp, and the external load limit as 2,300 lbs. The FAA had approved installation of a 1400 shp engine, and operations with an increased external load limit of 4,000 lbs.
The National Transportation Safety Board determines the probable cause(s) of this accident as follows.
Fatigue failure of the rotor transmission drive system, resulting from the improper certification/approval of the aircraft modification by the federal aviation administration.
I cannot quantify the overall number of accidents in commercial operation as I do not have access to the hours flown. However, from a very small fleet, there seems to be quite a number.
The same is true with the K-Max. A recent news report states that the the fleet leader has recently turned 10,000 hours. So with a relatively small fleet and overall low hours, I would not rush to too many assumptions.
H-43 is correct, they are really stout and simple machines - certainly Kaman's trademark, and one which is hard to beat in the real world of making money. The longevity of the aircraft is a pretty fair testament to that.
I have a number of acquaintances who have both flown and operated the H-43. One told me that when firefighting for the State of Washington Department of Natural Resources(DNR) they would always arrive on the scene of the fire at the same time as everyone else left, as they were so slow! (made for a very casual and relaxed summer)
I thought that the funniest comment however, was a mechanic who told me that there was no doubting that the machine was built by a bearing company. "You've never seen so many Kaman bearings in one place before, nor a piece of equipment that can use 'em up so fast!"
Now, about that weird control reversal deal - can't say I've run into that to many times before!