Aviation Accident Summaries

Aviation Accident Summary DEN92IA025

DENVER, CO, USA

Aircraft #1

N343UA

BOEING 737-300

Analysis

DURING CLIMB, THE CREW NOTED AN ELECTRICAL ARCING SOUND AND SLIGHT ELECTRICAL-TYPE BURNING ODOR WHILE PASSING THROUGH FLIGHT LEVEL 180. EMERGENCY PROCEDURES WERE COMPLIED WITH AND THE PROBLEM APPEARED TO BE SOLVED. THE CLIMB WAS CONTINUED, AND WHILE PASSING THROUGH FLIGHT LEVEL 330 A LOUD ARCING SOUND WAS AGAIN HEARD ACCOMPANIED BY FLAMES FROM THE FLIGHT DECK AFT OVERHEAD PANEL. THE FLIGHT ATTENDANTS EXTINGUISHED THE FIRE, AND THE FLIGHT RETURNED TO DENVER AND LANDED WITHOUT FURTHER INCIDENT. EXAMINATION DISCLOSED A SHORT IN A WIRE BUNDLE. THE BUNDLE WAS NOT SHIELDED OR ANCHORED AS THE OTHER MAJOR BUNDLE IN THE COMPARTMENT. THE SHORT WAS DUE TO THE BUNDLE CHAFING ON THE FLIGHT DECK ENTRY DOOR FRAME. IN ADDITION, TESTING REVEALED THAT THE WIRE GAUGE USED IN PART OF THIS APPLICATION WAS INSUFFICIENT FOR THE ELECTRICAL LOAD.

Probable Cause and Findings

AN ELECTRICAL SHORT CIRCUIT IN A MAIN WIRE BUNDLE DUE TO CHAFING OF THE BUNDLE ON AIRFRAME STRUCTURAL MEMBERS.

 

Source: NTSB Aviation Accident Database

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