A-02-049
NTSB Safety Recommendation — Aviation
Recommendation text
TO THE FEDERAL AVIATION ADMINISTRATION: Conduct a systematic engineering review to (1) identify means to eliminate the catastrophic effects of total acme nut thread failure in the horizontal stabilizer trim system jackscrew assembly in Douglas DC-9 (DC-9), McDonnell Douglas MD-80/90 (MD-80/90), and Boeing 717 (717) series airplanes and require, if practicable, that such fail-safe mechanisms be incorporated in the design of all existing and future DC-9, MD-80/90, and 717 series airplanes and their derivatives; (2) evaluate the horizontal stabilizer trim systems of all other transport-category airplanes to identify any designs that have a catastrophic single-point failure mode and, for any such system; (3) identify means to eliminate the catastrophic effects of that single-point failure mode and, if practicable, require that such fail-safe mechanisms be incorporated in the design of all existing and future airplanes that are equipped with such horizontal stabilizer trim systems.
In plain language (FlightFinder summary)
The FAA is asked to perform a systematic engineering review to find ways to prevent catastrophic failures from a complete acme nut thread failure in the horizontal stabilizer trim jackscrew on Douglas DC-9, McDonnell Douglas MD-80/90, and Boeing 717 series aircraft, and to mandate fail-safe design changes if feasible. Additionally, the FAA should examine horizontal stabilizer trim systems on other transport-category airplanes for any single-point failure modes that could be catastrophic, and require corrective measures where possible.
This plain-language summary is written by FlightFinder to explain the recommendation above. It is not the official wording — the verbatim NTSB text is quoted above.
Details
| Status | Closed - Acceptable Action |
|---|---|
| Mode | Aviation |
| Closed | Jan 31, 2011 |
| NTSB number | DCA00MA023 |
| Addressees | FAA |
External links
NTSB safety recommendations are advisory; addressees are not legally required to adopt them. Source: NTSB CAROL (public domain).