FAA n NTSB's 2 cents
on the
Alabama
Mini 5oo Crash
This Page was created
June 3rd, 2,oo1
.......Official USA Time, Hawaiian - Alaskan - Pacific Mountain - Central - Eastern - Caribbean
The NTSB report on the October 3, 2000 fatal crash of Dr. Amnon Katz has been issued, and describes the accident thus: "According to the airport control tower operator, the helicopter had completed three to four circuits in closed traffic to taxiway golf.
While on the downwind leg, the controller believed that the helicopter had a sudden loss of engine power and began to descend. The tower received no communications and the helicopter's rotor rpm decreased and appeared to stop before impact."
The Board also noted that the handling may have been affected by some modifications Dr. Katz made to the machine, outside of the kit's instructions: "The helicopter was assembled and inspected on April 4, 2000, and had accumulated a total time of 16 hours of flight time at the time of the accident. According to the aircraft logbook, on September 28, 2000, the pilot had modified the helicopters horizontal stabilizer by cutting off part of the stabilizer behind mounting plates number 88 and number 98, and removed the winglets.
The pilot flew 10 traffic patterns in new configuration. He noted in the logbook 'less objectionable side to side shaking, but balance still indicates vertical 1.5 ips in climb.'
However, according
to the FAA, this modification was not approved as required by
the experimental aircraft operating limitations. [When any Experimental
undergoes 'significant' changes, such as modification to a flying surface,
a re-inspection is required, and additional fly-off hours are generally
also added to the restrictions. The FAA does not offer opinions on the
efficacy of well-done mods --ed.]
Additionally, the helicopter was powered by a Rotax 582 engine. In the engine operator's Manual under section 9, entitled Danger! States in part that 'This engine, by its design, is subject to sudden stoppage! Engine stoppage can result in crash landings. Such crash landings can lead to serious bodily injury or death.'" The causes of the accident, according to the report, were "The loss of engine power for undetermined reasons, and the pilot's unproved airframe modification that resulted in the loss of flight control during the emergency descent." Just why that engine stopped is being investigated by the Rotax people.
[The real problem, of course, is that Dr. Katz knew he had a dangerous aircraft and set about trying to find fixes for its many problems... and died in the attempt.--EIC] FMI:
My (the host of this web site) 2 cents:
I have slightly over 130 hours under the Rotax 582 n have had only
MINOR problems. I also know of many many more Rotax
582 owners n pilots (helicopter n fixed wing) that also have had much
success with this power plant.......................... But my 582 is mounted
in an entirely different helicopter, in an entirely different manor with
a different cooling system. Also, the designer (Augusto
Cicare) of the helicopter I fly had designed n built
no less than 6 helicopters from scratch at the time he designed
my bird. The designer of the M5oo has only this helicopter to his credit
(or curse).
The Rotax 582 is a GOOD engine, but obviously the way junior designer mounted in this heavier helicopter causes it to fail reliably. Glen Ryerson
