McDonnell Douglas Helicopter Systems (MDHS) is meeting with the US Federal Aviation Administration to discuss design and certification options following another crash of an MD 600N on 18 January during the flight-test programme.
The eight place helicopter should have received FAA certification by mid-December 1996, despite earlier delays to the programme caused by the crash of the second prototype in May last year and subsequent modifications. Two further crashes, the first in November and the latest this month, now threaten to delay certification and handover for several months, however.
MDHS declines to give details of the incidents, or of any possible design changes, until its meeting with the FAA have been completed. The company confirms that no new target date for certification has been agreed. The two latest incidents appear to have been virtually identical, as both occurred at the end of an autorotative descent at the high- altitude Flagstaff Airport in Arizona.
No injuries to the crew were sustained in either event, though the helicopter in the January crash (RN02), was "pretty banged up" when it toppled on its side. The tests were being made as part of the final high-velocity curve evaluation of the flight characteristics.
MDHS introduced changes to the helicopter to increase main rotor blade to tailboom clearance following the May 28, 1996, accident. This occurred when the main rotor struck and partially severed the tailboom as the pilot performed control reversals in the longitudinal axis at maximum speed and minimum rotor RPM.
Source: Flight International
