NTSB Identification: LAX91LA129.
The docket is stored on NTSB microfiche number 44374.
Accident occurred Monday, March 11, 1991 in TUCSON, AZ
Probable Cause Approval Date: 03/24/1993
Aircraft: CESSNA 421B, registration: N924MD
Injuries: 3 Serious,3 Minor.

NTSB investigators may not have traveled in support of this investigation and used data provided by various sources to prepare this aircraft accident report.

THE PLT (PIC) WAS A PART 135 CHECK AIRMAN & WAS OCCUPYING THE RGT SEAT. A 2ND COMPANY PLT WAS IN THE L SEAT TO GET SOME TIME IN THE CESSNA 421. THE 2ND PLT MADE THE TAKEOFF & THE ACFT WAS 10 TO 15 SEC INTO THE INITIAL CLIMB, WHEN A LOSS OF PWR WAS DETECTED IN THE RGT ENG. A 3RD PLT (SITTING IN THE BACK) CALLED OUT THAT HE SAW FIRE COMING FM THE RGT ENG NACELLE. THE PIC STATED THAT THE 2ND PLT 'APPREHENSIVELY ATTEMPT(ED) THE EMERGENCY PROCEDURES & GAVE THE AIRPLANE TO ME AS (THE) AIRSPEED RAPIDLY DECLINED.' THE PIC SAID SOME PWR LINES WERE DRCTLY AHD & HE ELECTED TO GO UNDER THE WIRES TOWARD A VACANT FLD. THE ACFT COLLIDED WITH THE PWR LINES, THEN IMPACTED THE GND IN THE FLD. AN ON SITE EXAM OF THE ACFT REVEALED THE RGT ENG TURBOCHARGER EXHAUST CLAMP HAD FAILED, ALLOWING EXHAUST GASSES TO FLOW THRU LOUVERS IN THE RGT NACELLE. NO EVIDENCE OF AN ACTUAL FIRE WAS FND. A METALLURGICAL EXAM OF THE RGT ENG TURBO EXHAUST CLAMP REVEALED IT HAD FAILED FM FATIGUE.

The National Transportation Safety Board determines the probable cause(s) of this accident to be:

THE FATIGUE FAILURE OF THE RIGHT ENGINE TURBO EXHAUST CLAMP, AND, THE FAILURE OF THE FLYING PILOT TO COMPLETE THE SINGLE ENGINE EMERGENCY PROCEDURES IN A TIMELY MANNER. A FACTOR IN THE ACCIDENT WAS THE FAILURE OF THE PILOT IN COMMAND TO ADEQUATELY SUPERVISE THE CONDUCT OF THE FLIGHT.

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