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NTSB Report
March 12, 1991 · Cessna 421B · N924MD
Tucson, AZ
Overview
Report Status
Probable Cause
Event Type
Accident
Date
March 12, 1991
Injury Outcomes
6 injuries (3 serious injuries, 3 minor injuries)
Location
Tucson, AZ
Aircraft
Cessna 421B
Tail Number
N924MD
Operator
Deer Valley Aviation
Injuries
Serious
Aircraft Damage
Substantial
NTSB Number
LAX91LA129
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.
NTSB Probable Cause
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.
Full 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.
Flight
Event TypeAccident
Event Time18:58 MST
Nearest Airport0nm N
Runway0
Flight Plan FiledCvfr
Aircraft FireNo
Aircraft ExplosionNo
Aircraft
AircraftCessna 421B
Tail NumberN924MD
Aircraft CategoryAir
DamageSubstantial
OperatorDeer Valley Aviation
Operating RulePart 91
Engines2
Engine TypeReciprocating
Engine DetailsContinental · GTSIO-520-H · Reciprocating · 375
Seats8
People & Injuries
Injury Summary6 injuries (3 serious injuries, 3 minor injuries)
Fatal0
Serious3
Minor3
Uninjured0
Total6
Crew 1Age 37 · First Class
Conditions
ConditionsVMC
LightDusk
Wind310° @ 15 kt
Visibility30 sm
CeilingNone
Temperature / Dew Point0 C / 0 C
Altimeter0
Observation Time02:13
Weather SourceWFAC