Cessna 421B N924MD

Summary

On 12 March 1991 at about 01:58 local time, a Cessna 421B registered N924MD, operated by Deer Valley Aviation, Inc, was involved in an accident near Tucson, Arizona, United States. 6 people were on board and 3 were seriously injured, 3 had minor injuries. The aircraft was substantially damaged. The NTSB has published a probable cause for this accident; it is quoted in full below.

Date

12 March 1991 at 01:58

Classification

Accident

Location

Tucson, Arizona, United States

Coordinates

32.1504, -110.9307

Aircraft

Cessna 421B

Registration

N924MD

Category

Airplane

Engines

2

Operator

Deer Valley Aviation, Inc

Operating rule

Part 91: General Aviation

Purpose of flight

Positioning

Phase of flight

Not recorded

Route

Unknown → Scottsdale

Aircraft damage

Substantial

Weather

VMC

Light

Dusk

NTSB number

LAX91LA129

3 people were seriously injured.

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.

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

Read the full NTSB narrative

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.

Quoted verbatim from the NTSB record.