# NTSB MIA91FA023: Cessna 421B, N21ST, Flamingo, FL, November 9, 1990

- Type: NTSB accident investigation
- Classification: Accident · Fatal · Field investigation · Final report
- Date: November 9, 1990, 14:47 local (19:47 UTC)
- Place: Flamingo, FL
- Coordinates: 25.489368, -80.510681 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=25.4894&lon=-80.5107&mi=10
- Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping)
- Highest injury: Fatal
- Injuries: 3 fatal
- Status: Completed, report October 10, 1991
- Report: Approved by Office Director
- NTSB case key (mKey): 32737
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=MIA91FA023
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/32737/pdf
- Page: https://openairdocs.org/ntsb/MIA91FA023

## Probable cause

AN UNDETERMINED AIRFRAME/COMPONENT/SYSTEM FAILURE/MALFUNCTION,  WHICH RESULTED IN A FUEL FED FIRE IN THE LEFT WING.

## Sequence of events

In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf).

- Airframe/component/system failure/malfunction, cruise - normal
  - reason for occurrence undetermined (cause)
- Fire, cruise
  - fuel system - fire (cause)
  - wing - fire (cause)
  - wing,spar - burned
  - wing - separation
- In flight collision with terrain/water, descent - uncontrolled

## Analysis

AS THE ACFT (N21ST) WAS EN ROUTE ON A FLT FROM KEY WEST TO NAPLES, FL, THE PLT OF ANOTHER ACFT SAW A 'FIRE BALL' IN THE VCNTY OF WHERE N21ST SUBSEQUENTLY CRASHED. WHEN N21ST DID NOT ARRIVE, A SEARCH WAS INITIATED.  THE WRECKAGE WAS FND THE NEXT DAY AT 1704 EST, IN THE EVERGLADES NATL PARK, NR FLAMINGO, FL.  DRG IMPACT, THE MAIN WRECKAGE WAS BURIED IN 30' OF MUD.  THE LEFT OUTBOARD WING SECTION (FM JUST OUTBOARD OF THE ENG NACELLE TO THE WING TIP) WAS FND APRX 1 MI FM THE MAINWRECKAGE. AN EXAM REVEALED THE WING HAD FAILED WHERE THE NACELLE FUEL TANK & THE AUX FUEL TANK BOOST PUMPS WERE MOUNTED.NO EXHAUST SYS FAILURE OR LEAKAGE FM THE FUEL TANKS WAS FND IN THE AREA OF THE FIRE.  THE GREATEST FIRE DMG WAS AT A POINT WHERE THE LEFT NACELLE FUEL TANK BOOST PUMP WAS MOUNTED & AFT FM THERE TO WHERE THE REAR WING SPAR HAD BURNED THRU. THE ELEC FUEL BOOST PUMPS WERE NOT RECOVERED AFTER THE ACDNT. THE IGNITION SOURCE FOR THE FIRE WAS NOT DETERMINED.

## Aircraft

- Registration: [N21ST](https://openairdocs.org/deregistered/N21ST-1991-07-09), registration cancelled 1991-07-09, S/N 421B0963 (OpenAirDocs)
- Reported make and model: CESSNA 421B
- Registry model: [Cessna 421B](https://openairdocs.org/model/cessna-421b) (registry code 2076014) (OpenAirDocs)
- Category: Airplane
- Serial number: 421B-0963
- Airframe hours: 2741
- Engines: CONTINENTAL GTSIO-520-H 375 horsepower reciprocating
- Damage: Destroyed
- Fire: In-Flight
- Flight: Personal, Part 91
- Registered owner: St. Paul Aviation
- Airworthiness certificate: Standard, Normal
- Last inspection: Annual, June 28, 1990, 51 hours before
- Departed: EYW, KEY WEST, FL
- Destination: APF, NAPLES, FL

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 69; commercial; airplane ratings: single-engine land, multi-engine land; instrument ratings: airplane; medical: class 3, valid medical--w/ waivers/lim; seat: left; flight hours: 10,100 total, 50 in this make and model, 20 in the last 90 days, 15 in the last 30 days, 2 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Wind: 120° at 15 knots
- Visibility: 10 statute miles
- Lowest ceiling: 10,000 ft overcast
- Temperature: 88 °F, dew point 81 °F
- Altimeter: 29.00 inHg
- Observed at: MTH, 30 nm away

## FAA reports on this event (1)

The FAA's own accident and incident reports, matched to the aircraft by N-number and date (OpenAirDocs).

- [Accident 19901109050129A](https://openairdocs.org/incident/19901109050129A), Nov 9, 1990: Cessna 421B, Flamingo, FL, Destroyed, 3 fatal. Fire in left wing melted spar and explosion separated outboard section. Fuel leak in area. AD on boost pump overdue

From the NTSB's public API. Aircraft are matched to registry aircraft by N-number and event date, checked against the reported serial number, make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model.

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