Boeing 757-200ER N757NA

Summary

On 13 September 1993 at about 12:55 local time, a Boeing 757-200ER registered N757NA, operated by North American Airlines, was involved in an incident near Jamaica, New York, United States. 85 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

13 September 1993 at 12:55

Classification

Incident

Location

Jamaica, New York, United States

Coordinates

40.6507, -73.7908

Aircraft

Boeing 757-200ER

Registration

N757NA

Category

Airplane

Engines

2

Operator

North American Airlines

Operating rule

Part 121: Air Carrier

Purpose of flight

Unknown

Phase of flight

Not recorded

Route

Unknown → San Francisco

Aircraft damage

Not recorded

Weather

VMC

Light

Day

NTSB number

BFO93IA175

Nobody was injured.

THE FAILURE OF THE LEFT HYDRAULIC PRESSURE SWITCH, WHICH CAUSED THE LEFT YAW DAMPER MODULE TO BECOME INOPERATIVE RESULTING IN UNCOMMANDED RUDDER MOVEMENTS DURING FLIGHT.

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

Read the full NTSB narrative

DURING CRUISE FLIGHT, A RUDDER RATIO WARNING LIGHT APPEARED, FOLLOWED BY UNCOMMANDED RIGHT RUDDER MOVEMENT AND LEFT AILERON INPUT. THE AIRPLANE REMAINED UNDER CONTROL AND THE CREW COUNTERACTED THE RUDDER MOVEMENT MANUALLY. THE CAPTAIN ELECTED TO ABORT THE FLIGHT AND LANDED SAFELY AT THE DEPARTURE AIRPORT. THE RUDDER RATIO WARNING WAS DISPLAYED ON TWO SUBSEQUENT FLIGHTS, DESPITE REPEATED ATTEMPTS TO RESOLVE THE DISCREPANCY. AFTER THE FOURTH WARNING WAS DISPLAYED IN ABOUT TWO MONTHS, AN EXAMINATION OF THE LEFT YAW DAMPER MODULE REVEALED A MALFUNCTION IN THE LEFT HYDRAULIC PRESSURE SWITCH. THE UNIT WAS REMOVED AND REPLACED. NO FURTHER INCIDENTS INVOLVING A RUDDER RATIO WARNING WERE REPORTED.

Quoted verbatim from the NTSB record.