# NTSB DEN91LA112: Lars Avid Flyer, N49BP, Colorado Spring, CO, August 10, 1991

- Type: NTSB accident investigation
- Classification: Accident · No injuries · Limited investigation · Final report
- Date: August 10, 1991, 10:15 local (16:15 UTC)
- Place: Colorado Spring, CO
- Coordinates: 39.029335, -104.28923 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=39.0293&lon=-104.2892&mi=10
- Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping)
- Highest injury: No injuries
- Injuries: 1 uninjured
- Status: Completed, report March 10, 1993
- Report: Approved by Office Director
- NTSB case key (mKey): 18122
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=DEN91LA112
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/18122/pdf
- Page: https://openairdocs.org/ntsb/DEN91LA112

## Probable cause

THE PILOT'S DELAY IN FLARING THE AIRPLANE.  FACTORS WERE: (1) STUCK PISTON RINGS AND (2) THE PILOT'S FAILURE TO USE FLAPS.

## 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, cruise - normal
  - engine assembly,ring - jammed (contributing factor)
- Forced landing, descent - emergency
- Hard landing, landing - flare/touchdown
  - lowering of flaps - not used, pilot in command (contributing factor)
  - flare - delayed, pilot in command (cause)
- Main gear collapsed, landing - roll

## Analysis

THE PILOT REPORTED HEARING TWO SUCCESSIVE LOUD EXPLOSIONS.  ENGINE RPMS DROPPED FROM 6500 TO 2800-3000, AND THE ENGINE DID NOT RESPOND TO THROTTLE APPLICATION.  THE PILOT MADE A NO-FLAP FORCED LANDING.  WHEN HE ATTEMPTED TO FLARE WITH FULL AFT ELEVATOR, THERE WAS NO RESPONSE.  CONTROL CONTINUITY WAS LATER ESTABLISHED.  THE ENGINE WAS FUNCTIONALLY TESTED AND DEVELOPED FULL POWER.  SUBSEQUENT ENGINE DISASSEMBLY DISCLOSED THE PISTON RINGS WERE STUCK IN THE RING GROOVES.

## Aircraft

- Registration: [N49BP](https://openairdocs.org/deregistered/N49BP-2012-12-10), registration cancelled 2012-12-10, S/N 216, built 1986 (OpenAirDocs)
- Reported make and model: LARS AVID FLYER
- Registry model: [Giertz Lars M AVID FLYER](https://openairdocs.org/model/giertz-lars-m-avid-flyer) (registry code 056121K) (OpenAirDocs)
- Registry engine: [Bombardier ROTAX (ALL)](https://openairdocs.org/engine/bombardier-rotax-all) (registry code 09050, reciprocating) (OpenAirDocs)
- Category: Airplane, amateur-built
- Serial number: 216
- Engines: Bombardier ROTAX 532 65 horsepower reciprocating
- Damage: Substantial damage
- Flight: Personal, Part 91
- Operator: Muenzel, Hans G.A.
- Registered owner: Muenzel, Hans G.A.
- Departed: C050, ELLICOTT, CO

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 63; commercial; airplane ratings: single-engine land; instrument ratings: airplane; medical: class 3, valid medical--no waivers/lim.; flight hours: 347 total, 13 in this make and model, 317 as pilot in command, 1 in the last 90 days, 1 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Wind: 160° at 5 knots
- Visibility: 50 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).

- [Accident 19910810033069A](https://openairdocs.org/incident/19910810033069A), Aug 10, 1991: Amtr AVIDFLYER, Colorado Spring, CO, Substantial damage. Engine lost power. Stalled on flare for forced landing. Piston rings fouled by excessive carbin. Lost compression.

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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