Aviation Accident Summaries

Aviation Accident Summary DCA95MA007

FRESNO, CA, USA

Aircraft #1

N521PA

LEARJET 35A

Analysis

AT ABOUT 1146 PST, LEARJET 35A, N521PA, OPERATING AS A PUBLIC USE AIRCRAFT, CRASHED IN FRESNO, CA. OPERATING WITH CALL SIGN DART 21, THE FLIGHTCREW HAD DECLARED AN EMERGENCY INBOUND TO FRESNO AIR TERMINAL DUE TO ENGINE FIRE INDICATIONS. THEY FLEW THE AIRPLANE TOWARD A RIGHT BASE FOR THEIR REQUESTED RUNWAY, BUT THE AIRPLANE CONTINUED PAST THE AIRPORT. THE FLIGHTCREW WAS HEARD ON TOWER FREQUENCY ATTEMPTING TO DIAGNOSE THE EMERGENCY CONDITIONS AND CONTROL THE AIRPLANE UNTIL IT CRASHED, WITH LANDING GEAR DOWN, ON AN AVENUE IN FRESNO. BOTH PILOTS WERE FATALLY INJURED. TWENTY-ONE PERSONS ON THE GROUND WERE INJURED, AND 12 APARTMENT UNITS IN 2 BUILDINGS WERE DESTROYED OR SUBSTANTIALLY DAMAGED BY IMPACT OR FIRE. INVESTIGATION REVEALED THAT SPECIAL MISSION WIRING WAS NOT INSTALLED PROPERLY, LEADING TO A LACK OF OVERLOAD CURRENT PROTECTION. THE IN-FLIGHT FIRE MOST LIKELY ORIGINATED WITH A SHORT OF THE SPECIAL MISSION POWER SUPPLY WIRES IN AN AREA UNPROTECTED BY CURRENT LIMITERS. THE FIRE RESULTED IN FALSE ENGINE FIRE WARNING INDICATIONS TO THE PILOTS THAT LED THEM TO A SHUTDOWN OF THE LEFT ENGINE. AN INTENSE FIRE BURNED THROUGH THE AFT ENGINE SUPPORT BEAM, DAMAGING THE AIRPLANE STRUCTURE AND SYSTEMS IN THE AFT FUSELAGE AND MAY HAVE PRECLUDED A SUCCESSFUL EMERGENCY LANDING. (FOR FURTHER INFORMATION, SEE NTSB/AAR-95/04)

Factual Information

The flight was inbound to FAT following an operational exercise with two ANG F-16s. Northeast of the airport, about 9,000 feet MSL, VFR, the flight called approach control, declared an emergency due to engine fire and requested immediate vectors to the airport. Approach control asked the flight which runway they requested and the flight replied 29. The flight was seen on radar at 6, and then 4 nautical miles at 4,000 feet MSL, with the airport at 12 O'clock. The flight reported field in sight and was handed over to the tower. Intracockpit conversations were transmitted on tower frequency until impact. A pilot mentioned possibly having to make a 270 degree turn, but the flight was seen passing through the extended centerline of runway 29, about 1 1/2 miles from the approach end of the runway, appearing to be low and fast. The airplane impacted to the west on Olive Avenue. Witnesses reported that the airplane impacted in a nose low and left wing down attitude. The airplane immediately became a fireball which slid down the avenue. Several apartments on the north side of the avenue became ignited. Some major airplane components, including the right wing, right engine, and empennage came to rest on the avenue. The left engine came to rest in an apartment unit. Both pilots were fatally injured. There were injuries to persons on the ground. ADDITIONAL PERSONS: Douglas E. Mooradian Airports Operations Manager Department of Airports 2401 N. Ashley Way Fresno, CA 93727 Lieutenant Jerry Davis Police Department City of Fresno 2326 Fresno Street Fresno, CA 93721 Franklin D. Schick Manager, Airworthiness R&D Learjet, Inc. One Learjet Way Wichita, KS 67277 Charles R. Mote, Jr. Air Safety Investigator National Air Traffic Controllers Association 13036 Treecrest St. Poway, CA 92064 Fred W. Kirby Manager, Technical Services National Business Aircraft Association, Inc. 1200 Eighteenth St., N.W. Washington, D.C. 20036 Patrick W. Murphy Phoenix Air Group, Inc. Director of Maintenance 100 Phoenix Air Drive, S.W. Cartersville, Georgia 30120

Probable Cause and Findings

1) IMPROPERLY INSTALLED ELECTRICAL WIRING FOR SPECIAL MISSION OPERATIONS THAT LED TO AN IN-FLIGHT FIRE THAT CAUSED AIRPLANE SYSTEMS AND STRUCTURAL DAMAGE AND SUBSEQUENT AIRPLANE CONTROL DIFFICULTIES; 2) IMPROPER MAINTENANCE AND INSPECTION PROCEDURES FOLLOWED BY THE OPERATOR; AND 3) INADEQUATE OVERSIGHT AND APPROVAL OF THE MAINTENANCE AND INSPECTION PRACTICE BY THE OPERATOR IN THE INSTALLATION OF THE SPECIAL MISSION SYSTEMS.

 

Source: NTSB Aviation Accident Database

Get all the details on your iPhone or iPad with:

Aviation Accidents App

In-Depth Access to Aviation Accident Reports