# NTSB DEN91IA046: Avions Marcel Dassault Mistert Falcon 900, N90EW, Eagle, CO, February 18, 1991

- Type: NTSB incident investigation
- Classification: Incident · No injuries · Incident investigation · Final report
- Date: February 18, 1991, 16:00 local (23:00 UTC)
- Place: Eagle, CO
- Coordinates: 39.649536, -106.820755 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=39.6495&lon=-106.8208&mi=10
- Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping)
- Highest injury: No injuries
- Injuries: 7 uninjured
- Status: Completed, report May 5, 1993
- Report: Approved by Office Director
- NTSB case key (mKey): 18041
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=DEN91IA046
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/18041/pdf
- Page: https://openairdocs.org/ntsb/DEN91IA046

## Probable cause

IMPROPER ENGINE MAINTENANCE BY MAINTENANCE PERSONNEL, IMPROPER ASSEMBLY OF THE COMBUSTION ASSEMBLY TRANSITION LINER, AND THE RUPTURE OF THE FIRST STAGE LP TURBINE WHEEL.

## Sequence of events

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

- Loss of engine power(total) - mech failure/malf, climb - to cruise
  - combustion assembly,transition liner - assembly (cause)
  - maintenance - improper, company maintenance personnel (cause)
  - turbine assembly,turbine wheel - ruptured (cause)
- Forced landing, descent - emergency

## Analysis

N90EW WAS IN A CLIMBING TURN PASSING THROUGH 11500 FEET WHEN THE FLIGHT CREW FELT AND HEARD AN EXPLOSION.  COCKPIT INSTRUMENTS INDICATED THAT THE LEFT ENGINE HAD FAILED.  THE ENGINE WAS SECURED AND THE AIRCRAFT RETURNED TO EAGLE COUNTY AIRPORT WITHOUT FURTHER INCIDENT.  A SUBSEQUENT ENGINE EXAMINATION REVEALED AN ERROR OCCURRED IN THE ASSEMBLY OF THE MATING OF THE INNER TRANSITION LINER TO THE HP TURBINE NOZZLE DURING THE LAST MAJOR PERIODIC MAINTENANCE INSPECTION.

## Aircraft

- Registration: N90EW (not matched to a registry record)
- Reported make and model: AVIONS MARCEL DASSAULT MISTERT FALCON 900 (MISTERT FA)
- Category: Airplane
- Serial number: 27
- Engines: GARRETT TFE 731-5 4500 horsepower turbo jet
- Damage: Minor damage
- Flight: Business, Part 91
- Operator: Aviations Methods, Inc.
- Departed: EGE, EAGLE, CO
- Destination: SFO, SAN FRANCISCO, CA
- Flight plan: VFR/IFR

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 49; airline transport; airplane ratings: multi-engine land, single-engine land; instrument ratings: airplane; medical: valid medical--no waivers/lim.; seat: left; flight hours: 13,000 total, 1,000 in this make and model, 12,000 as pilot in command, 110 in the last 90 days, 40 in the last 30 days

## Weather

- Conditions: Visual (VMC), Day
- Wind: calm
- Visibility: 20 statute miles
- Lowest ceiling: none
- Temperature: -0 °F, dew point -0 °F

## FAA reports on this event (1)

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

- [Incident 19910218007109I](https://openairdocs.org/incident/19910218007109I), Feb 18, 1991: Amd FALCON900, Eagle, CO, Minor damage. NR1 engine failed on climb. Returned. Landed safely. Found NR1 lp turbine blades and H6B assembly departed engine.

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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