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| Date: | Friday 28 April 1995 |
| Time: | 12:00 LT |
| Type: |  Airbus A320-211 |
| Owner/operator: | Northwest Airlines |
| Registration: | N331NW |
| MSN: | 318 |
| Year of manufacture: | 1992 |
| Engine model: | CFMI CFM56-5 |
| Fatalities: | Fatalities: 0 / Occupants: 90 |
| Other fatalities: | 0 |
| Aircraft damage: | None |
| Category: | Serious incident |
| Location: | Minneapolis, MN -
 United States of America
|
| Phase: | En route |
| Nature: | Unknown |
| Departure airport: | , MN (KMSP) |
| Orange County, CA | |
| Investigating agency: | NTSB |
| Confidence Rating: |  Accident investigation report completed and information captured |
ON TWO CONSECUTIVE DAYS, THE SAME AIRPLANE EXPERIENCED UNCOMMANDED ROLLS DURING FLIGHT WITH THE AUTOPILOT ENGAGED. INSPECTION OF THE AIRPLANE SYSTEMS REVEALED A DEFECT IN A ROLL POTENTIOMETER LOCATED IN THE CAPTAINS SIDESTICK TRANSDUCER UNIT. A GREASE FILLED GROOVE WAS FOUND IN THE POTENTIOMETER TRACK NEAR THE NEUTRAL POSITION. THIS POTENTIOMETER SENDS ELECTRONIC SIGNALS TO THE ELEVATOR AILERON CONTROLLER (ELAC-1). THE GROOVE RESULTED IN AN INTERMITTENT LOSS OF CONTACT BETWEEN THE WIPER AND THE TRACK AND SUBSEQUENTLY A 'VOLTAGE SPIKE' TO THE ELAC-1. FOLLOWING THIS INCIDENT AIRBUS ISSUED TWO SERVICE BULLETINS ADDRESSING THE 'VOLTAGE SPIKE' PHENOMENON WHICH HAS BEEN OCCURRING ON OTHER A320 AIRPLANES SINCE 1991.
Probable Cause: inadequate design of the fly-by-wire flight control system which allowed false signals from the sidestick transducer units to generate uncommanded rolls.
Accident investigation:
 |
|
Sources:
NTSB CHI95IA342
History of this aircraft
Other occurrences involving this aircraft
| 27 April 1995 | N331NW | Northwest Airlines | 0 | Washington, DC | |
non |
| 20 October 2007 | N331NW | Northwest Airlines | 0 | Fargo, ND | |
min |
| 10 November 2011 | N331NW | Delta Air Lines | 0 | near Minneapolis-St. Paul International Airport, MN (MSP) | |
sub |
| 1 April 2018 | N331NW | Delta Air Lines | 0 | Nassau-Lynden Pindling International Airport (NAS/MYNN) |  |
non |
Location
Revision history:
| Date/time | Contributor | Updates |
|---|---|---|
| 15-Mar-2024 06:45 | ASN Update Bot | Added |
Corrections or additions? ... Edit this accident description
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