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LAX91LA129 · Cessna 421B

11 Mar 1991 · Tucson, AZ, United States

Deer Valley Aviation Cessna 421B · Accident: partial loss of engine power (mechanical failure) during initial climb

From an unrecorded airport to Scottsdale Airport (SDL)

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Event

NTSB case
LAX91LA129
Event typeAccident: someone killed or seriously injured, or the aircraft substantially damaged (NTSB definition). Incident: an occurrence that affected or could have affected safety, short of that. Glossary
Accident
InvestigationHow far the investigation had got when the record was published: preliminary, ongoing, final or completed. Unknown where the source does not say. Glossary
Completed
API-reported fatalities
0 · all aircraft and ground
Ground fatalities
0
OperationWhat kind of flying it was, grouped by the rules it flew under: airline (US Part 121), air taxi and commuter (Part 135), general aviation (Part 91 and similar), military or government. Glossary
General aviation
WeatherVisual meteorological conditions (VMC): good enough to fly by looking outside. Instrument conditions (IMC): cloud or low visibility, flying by instruments. Glossary
Visual Meteorological Cond

Cessna 421B

Aircraft type
Cessna 421
Category
Airplane
RegistrationThe aircraft's tail number, such as N12345 or G-ABCD. Registrations are reissued, so the same one years apart can be a different aircraft. Glossary
N924MD
Onboard fatalities
Unknown
Route
From not recordedTo Scottsdale Airport (SDL), Scottsdale, AZ
Aircraft age
Not recorded
Flight rulesThe regulations the flight operated under: in the US, Part 91 (general aviation), Part 121 (airlines), Part 135 (air taxi and commuter) and others; for flights abroad, the NTSB's coarser commercial or non-commercial code. Glossary
Part 91: General Aviation
Phase of flightThe stage of the flight when things started to go wrong: standing, taxi, takeoff, initial climb, en route, maneuvering, approach or landing. Glossary
Initial climb
First occurrenceThe single coded event the NTSB judges best describes what happened (records from 2008 on). Older records name the first occurrence in the sequence instead. Glossary
Partial loss of engine power (mechanical failure)
Also codedOther events the NTSB coded in the sequence, such as a wire strike after a loss of power. Flight Findings uses them for its kinds of event. Glossary
Wire, transmission
DamageDestroyed: beyond practical repair. Substantial: damage that affects the structure, performance or handling and normally needs major repair. Minor: less than that. Glossary
Substantial

Cause areas

  • Copilot/second pilot › Emergency procedure, delayed
  • Copilot/second pilot › Propeller feathering, delayed
  • Exhaust system, clamp › Failure, total
  • Exhaust system, clamp › Fatigue
  • Pilot in command › Remedial action, delayed

Approximate · Coordinates as recorded by the NTSB; no uncertainty radius is established.

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.

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.

Verbatim NTSB analysis and probable cause from the NTSB dataset

Sources

NTSB record LAX91LA129
Event ID
20001212X16630
Case number
LAX91LA129
Dataset
historical-pre2008
Source SHA-256
89e2df6d848e7ab3b42e7d7c7a03ff403303057a26ca04c95b3ea67201c3ce74
Source notes (4)
  • Unreviewed is an editorial label, not an investigation status. API-sourced is not report-checked or human-reviewed. Explicit event totals are used without summing aircraft injury tables; onboard allocation is withheld. Unknown values remain unknown. The operation category is mapped from the NTSB-reported FAR part and has not been reviewed.
  • Filled from the NTSB case API where the bulk record had no value: local date, investigation status. Values present in the bulk record are kept.
  • The date is the local date; the NTSB stores the UTC date 1991-03-12.
  • API snapshot SHA-256: 0d13bac0e9c0083886ae44571c66713defc4963d98bfc64dec1d5fb28ed3cb8f; retrieved 2026-09-21T15:30:34.145Z.