Airbus A-320 N347NW

Summary

On 14 June 1996 at about 14:57 local time, a Airbus A-320 registered N347NW, operated by Northwest Airlines, was involved in an incident near Boston, Massachusetts, United States. 106 people were on board and nobody was injured. The NTSB has published a probable cause for this accident; it is quoted in full below.

Date

14 June 1996 at 14:57

Classification

Incident

Location

Boston, Massachusetts, United States

Coordinates

Not recorded

Aircraft

Airbus A-320

Registration

N347NW

Category

Airplane

Engines

2

Operator

Northwest Airlines

Operating rule

Part 121: Air Carrier

Purpose of flight

Unknown

Phase of flight

Not recorded

Route

Unknown → Detroit

Aircraft damage

Not recorded

Weather

VMC

Light

Day

NTSB number

CHI96IA207

Nobody was injured.

an undetermined intermittent fault in the trimmable horizontal stabilizer actuator system.

Quoted verbatim from the NTSB record. This site does not paraphrase or interpret it.

Read the full NTSB narrative

The pilot reported that a two to three degree uncommanded pitch decrease occurred about 600 feet above ground level at the same time as a flight control system pitch warning fault message was received. The crew declared an emergency and landed without further incident. During troubleshooting, the maintenance technician reported the right half of the stabilizer trim control package felt hot to the touch. The left side was cool. The trimmable horizontal stabilizer (THS) actuator was replaced, and the airplane was returned to service without further incident. Examination of the airplane logbooks revealed flight control system, pitch axis, discrepancies, and maintenance action following the previous two flights. Both elevator aileron computers, the THS electronic module, the THS actuator position monitor, and the pitch trim motor were replaced. Examination of the flight data recorder revealed erratic stabilizer movement on the previous two flights. The THS actuator and the pitch trim actuator servo motor functioned normally when tested. A defective diode was discovered in the electronic module. An Airbus Industries engineer reported the pitch oscillations could not be attributed to the defective diode.

Quoted verbatim from the NTSB record.