# NTSB DEN86LA127: Glaser-Dirks DG-400, N40Z, Longmont, CO, May 4, 1986

- Type: NTSB accident investigation
- Classification: Accident · Minor injuries · Limited investigation · Final report
- Date: May 4, 1986, 16:50 local (22:50 UTC)
- Place: Longmont, CO
- Coordinates: 40.170108, -105.109031 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=40.1701&lon=-105.1090&mi=10
- Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping)
- Highest injury: Minor injuries
- Injuries: 1 minor
- Status: Completed
- Report: Approved by Office Director
- NTSB case key (mKey): 16958
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=DEN86LA127
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/16958/pdf
- Page: https://openairdocs.org/ntsb/DEN86LA127

## Sequence of events

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

- Airframe/component/system failure/malfunction, descent - normal
  - engine assembly - inoperative (cause)
  - reason for occurrence undetermined
- Forced landing, descent - emergency
  - in-flight planning/decision - delayed, pilot in command (cause)
- In flight collision with object, approach - vfr pattern - final approach
  - object - tree(s)

## Analysis

THIS EXPERIMENTAL GLIDER HAS A STOWABLE 2 CYCLE ENG MOUNTED BEHIND THE COCKPIT. WHEN THE ENG IS STOWED THE GLIDE RATIO IS ABOUT 40:1. WHEN THE ENG IS DEPLOYED BUT NOT RUNNING, THE GLIDE RATIO IS ABOUT 10:1. WHILE RETURNING AFTER A 4 HR AND 50 MIN FLT THE PLT DECIDED ENG PWR WOULD BE NEEDED TO REACH THE ARPT. HE DEPLOYED THE ENG BUT IT WOULD NOT START. AN OFF ARPT FORCED LANDING WAS NECESSARY AND THE ACFT HIT A TREE.

## Aircraft

- Registration: [N40Z](https://openairdocs.org/aircraft/N40Z), registered now, S/N 4-144 (OpenAirDocs)
- Reported make and model: GLASER-DIRKS DG-400
- Registry model: [Glaser-Dirks DG-400M/17](https://openairdocs.org/model/glaser-dirks-dg-400m-17) (registry code 3802550) (OpenAirDocs)
- Registry engine: [Bombardier ROTAX (ALL)](https://openairdocs.org/engine/bombardier-rotax-all) (registry code 09050, reciprocating) (OpenAirDocs)
- Category: Glider
- Serial number: 4-144
- Airframe hours: 43
- Engines: ROTAX 2 CYCLE 43 horsepower reciprocating
- Damage: Substantial damage
- Flight: Personal, Part 91
- Registered owner: Howard W. Selby, III
- Airworthiness certificate: Special, Experimental (Special)
- Last inspection: Annual, October 31, 1985, 43 hours before
- Departed: 1V5, BOULDER, CO
- Flight plan: VFR

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 43; private; airplane ratings: single-engine land, multi-engine land; instrument ratings: airplane; medical: class 3, valid medical--w/ waivers/lim; flight hours: 1,278 total, 43 in this make and model, 79 in the last 90 days, 5 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Wind: 200° at 20 knots
- Visibility: 75 statute miles
- Lowest ceiling: 10,000 ft broken
- Temperature: 82 °F
- Altimeter: 29.00 inHg
- Observed at: BJC, 19 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 19860504019689A](https://openairdocs.org/incident/19860504019689A), May 4, 1986: Amtr DG400, Longmont, CO, Substantial damage. Could not restart the engine of the glider. Struck a tree on landing. This type engine is routinely hard to start.

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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