This was forwarded to me from a friend; I don't know the original
source. It is NOT an April Fool's joke. The original message was
written 2 days ago.
> Date: Wed, 30 Mar 1994 18:25:42 -0800 (PST)
> From: "Stephen A. Stough" <sastough@rahul.net>
>
> Final report blames Lucas design, Lockheed's procedures for HTTB crash
>
> Federal safety officials yesterday blamed an inadequate actuator
> design by Lucas Aerospace and Lockheed's failure to take account of its
> shortcomings for the crash last year of Lockheed's one-of-a-kind High
> Technology Test Bed plane.
> In its final report on the Feb. 3, 1993, crash at Dobbins AFB, Ga.,
> the National Transportation Safety Board said the plane lost all rudder
> control during a high-speed taxi test with a simulated No. 1 engine
> failure when an experimental fly-by-wire control system for the rudder
> disengaged.
> "The disengagement was a result of the inadequate design of the
> rudder's integrated actuator package by its manufacturer," NTSB said.
> A design feature in the actuator removes hydraulic pressure if the
> rudder position commanded by the pilot exceeds the actual rudder
> actuator position for a specified time, and the rudder position trails,
> according to the report.
> Lucas Aerospace designed the package, a self-contained unit
> configured to be a drop-in replacement for the existing Hercules/HTTB
> dual tandem rudder actuator.
> The HTTB had recently been modified to evaluate power-by-wire
> flight control systems developed by Lockheed, along with some 50
> suppliers. Lucas' package was demonstrated on two flights in March
> 1992, which Lockheed, claiming success, noted was the first time the
> concept had been tested on a manned flight.
> Still, NTSB said that on at least one occasion the actuator had
> previously disengaged in flight, but "the company did not conduct a
> system safety review of the rudder bypass feature and its consequences
> to all flight regimes, nor of the (ground minimum control speed) test."
> The fact that neither pilot was trained as a flight test engineer
> contributed to the accident, the report said.
> "I do want to emphasize that the seven crew members were extremely
> qualified for the jobs they were doing," a Lockheed spokesman said in a
> prepared statement. "We still feel a great sense of loss for these
> colleagues and we praise their contributions to aviation. Beyond that,
> we prefer not to comment on the NTSB report, the investigation, or the
> accident."
> The highly modified L-100-20 Hercules transport was not programmed
> to become airborne, NTSB Chairman Carl Vogt said shortly after the
> accident (DAILY, Feb. 5, 1993, page 200). But an NTSB spokesman told The
> DAILY yesterday that "it is the analysis of the board that (the pilot)
> attempted to get the plane airborne at that moment," although to this
> day nobody knows why the takeoff was attempted.
> The report noted that the flight test plan specified that engine
> power be retarded if the rudder became ineffective. The aircraft was at
> full power but had not reached takeoff speed when it briefly became
> airborne, clipped a Navy clinic and crashed about 200 yards north of the
> runway, killing all seven aboard.
> Lockheed said it was reviewing the NTSB's data, adding that "action
> will be taken as appropriate."
--
T.J. Higgins | tjhiggin@ingr.com | (205) 730-7922
Intergraph Corp. | Mapping Sciences Division | Huntsville, AL, USA
|