# NTSB DEN91LA066: Cessna 421, N18DF, Englewood, CO, May 1, 1991

- Type: NTSB accident investigation
- Classification: Accident · Minor injuries · Limited investigation · Final report
- Date: May 1, 1991, 06:00 local (12:00 UTC)
- Place: Englewood, CO
- Coordinates: 39.640045, -104.989654 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=39.6400&lon=-104.9897&mi=10
- Phase of flight: [Initial climb](https://openairdocs.org/ntsb-phases/350) (OpenAirDocs' grouping)
- Highest injury: Minor injuries
- Injuries: 1 minor, 4 uninjured
- Status: Completed, report May 5, 1993
- Report: Approved by Office Director
- Safety recommendations: Yes
- NTSB case key (mKey): 18086
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=DEN91LA066
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/18086/pdf
- Page: https://openairdocs.org/ntsb/DEN91LA066

## Probable cause

POWER LOSS ON BOTH ENGINES AS A RESULT OF EXHAUST SYSTEM FAILURE.

## Sequence of events

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

- Loss of engine power(partial) - mech failure/malf, takeoff - initial climb
  - exhaust system,manifold/pipe - fractured (cause)
  - exhaust system,manifold/pipe - cracked (cause)
- Loss of engine power(total) - mech failure/malf, maneuvering - turn to landing area (emergency)
  - terrain condition - rough/uneven (contributing factor)
  - terrain condition - soft (contributing factor)

## Analysis

DURING INITIAL CLIMB AFTER TAKEOFF FROM A HIGH ALTITUDE AIRPORT AND AT A GROSS WEIGHT 70 POUNDS BELOW MAXIMUM, BOTH ENGINE LOST INPUT TO THEIR TURBOCHARGERS DUE TO EXHAUST SYSTEM FAILURE.  AT THE REDUCED POWER AVAILABLE, THE PILOT WAS UNABLE TO RETURN TO THE AIRPORT AND CONDUCTED AN EMERGENCY LANDING IN A FIELD.  THE TERRAIN WAS ROLLING, SOFT, AND THE LANDING GEAR COLLAPSED DURING LANDING ROLL.  THE ENGINE NACELLES AND UNDERSIDE OF THE AIRCRAFT WERE DAMAGED AS THE AIRCRAFT SLID DURING THE FINAL PHASE OF DECELERATION.

## Aircraft

- Registration: [N18DF](https://openairdocs.org/deregistered/N18DF-1991-08-09), registration cancelled 1991-08-09, S/N 4210126 (OpenAirDocs)
- Reported make and model: CESSNA 421
- Registry model: [Cessna 421](https://openairdocs.org/model/cessna-421) (registry code 2076010) (OpenAirDocs)
- Category: Airplane
- Serial number: 421-126
- Engines: CONTINENTAL GTSIO-5200 375 horsepower reciprocating
- Damage: Substantial damage
- Flight: Personal, Part 91
- Operator: Executive Airmotive
- Registered owner: Executive Airmotive
- Destination: K61, BELOTT, KS
- Airport: APA, Centennial

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 39; airline transport, commercial; airplane ratings: multi-engine land, single-engine land; instrument ratings: airplane; medical: class 1, valid medical--w/ waivers/lim; flight hours: 9,600 total, 300 in this make and model, 6,200 as pilot in command, 220 in the last 90 days, 80 in the last 30 days

## Weather

- Conditions: Visual (VMC), Day
- Wind: 190° at 4 knots
- Visibility: 50 statute miles
- Lowest ceiling: none
- Temperature: -0 °F, dew point -0 °F
- Observed at: APA, 1 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 19910501013889A](https://openairdocs.org/incident/19910501013889A), May 1, 1991: Cessna 421, Denver, CO, Substantial damage. Lost both engines on initial climbout. Collapsed gear landing in a field. Both exhaust pipes failed at welds.

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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