DCA95MA007

NTSB accident investigation · Learjet 35A · Fresno, CA · December 14, 1994

Accident · FatalClass 1 · MajorFinal report
Date
December 14, 1994, 11:46 local (19:46 UTC)
Place
Fresno, CA
Injuries
2 fatal, 1 serious, 20 minor; on the ground: 1 serious, 20 minor
Damage
Destroyed
Phase of flight
Enroute
Aircraft
N521PALearjet 35A
Weather
Visual (VMC) · Day
Status
Completed · report February 27, 1996
Report
Board-adopted at Board Meeting
Investigation class
Class 1
NTSB office
Major Investigations Division
Safety recommendations
Yes
Case key
10994

From the NTSB’s public API. By law, NTSB reports can’t be used as evidence in lawsuits over the accident.

On this page

Probable cause

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.

Sequence of events

NTSB’s coding before 2008: each occurrence and phase of flight, and the causes and factors under it. The codes are defined in NTSB’s coding manual.

Airframe/component/system failure/malfunctionDescent
Electrical system,electric wiring - improperCause
Maintenance,installation - improperCompany/operator managementCause
Inadequate surveillance of operationCompany/operator mgmtCause
Electrical system,electric wiring - shortedCause
Fire/explosionDescent
Fuselage - fireCause
Fire warning system,powerplant - false indication
Engine shutdown - performed
Forced landingEmergency descent/landing
In flight collision with terrain/waterEmergency landing

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 narrative

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

Aircraft

Registration
N521PA
Reported as
Learjet 35A
Category
Airplane
Serial number
239
Airframe hours
6,673
Engine
Garrett TFE 731-2-2B, 3,400 lbs thrust, turbo fan
Damage
Destroyed
Fire
In-Flight
Flight
Public aircraft · Public use
Registered owner
Phoenix Air Group, Inc.
Airworthiness certificate
Standard, Normal
Last inspection
AAIP · November 14, 1994 · 50 hours before
Departed
FAT
Destination
FAT
Flight plan
VFR/IFR
Airport
FAT · Fresno Air Terminal, runway 29R, 9,222 × 150 ft, asphalt

Matched to the registry by N-number and the event date; the registry’s history has gaps, so older matches can be wrong. Compare the reported make and model.

Flight crew

As NTSB recorded them. NTSB leaves out names.

Role
Pilot
Age
36
Certificates
Flight instructor, Airline transport, Commercial
Airplane ratings
Multi-engine land, Single-engine land
Instrument ratings
Airplane
Medical
Class 1, Valid Medical--no waivers/lim.
Seat
Left
Toxicology
Performed
Flight hours
7,109 total · 2,747 in this make and model

Weather

Conditions
Visual (VMC) · Day
Wind
120° at 9 knots
Visibility
20 statute miles
Lowest ceiling
10,000 ft broken
Temperature
48 °F, dew point 39 °F
Altimeter
30.00 inHg
Observed at
FAT, 2 nm away