# NTSB DEN89LA148: Piper PA-18-150, N4137Z, Durango, CO, June 26, 1989

- Type: NTSB accident investigation
- Classification: Accident · No injuries · Limited investigation · Final report
- Date: June 26, 1989, 10:15 local (16:15 UTC)
- Place: Durango, CO
- Coordinates: 37.269424, -107.879043 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=37.2694&lon=-107.8790&mi=10
- Phase of flight: [Landing](https://openairdocs.org/ntsb-phases/550) (OpenAirDocs' grouping)
- Highest injury: No injuries
- Injuries: 1 uninjured
- Status: Completed, report June 28, 1991
- Report: Approved by Office Director
- NTSB case key (mKey): 17730
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=DEN89LA148
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/17730/pdf
- Page: https://openairdocs.org/ntsb/DEN89LA148

## Probable cause

THE PILOT FAILED TO MAINTAIN DIRECTIONAL CONTROL, WHICH RESULTED IN AN INADVERTENT GROUNDLOOP/SWERVE. A FACTOR RELATED TO THE ACCIDENT WAS:  THE ADVERSE WIND CONDITION.

## Sequence of events

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

- Loss of control - on ground/water, landing - roll
  - weather condition - tailwind (contributing factor)
  - weather condition - crosswind (contributing factor)
  - directional control - not maintained, pilot in command (cause)
  - ground loop/swerve - inadvertent, pilot in command (cause)
- Dragged wing,rotor,pod,float or tail/skid, landing - roll

## Analysis

DURING A GLIDER TOW FLT, THE PLT TOOK OFF TO THE SOUTH.  AFTER RELEASING THE GLIDER, HE RETURNED & LANDED TO THE NORTH WITH A 5 KT QUARTERING TAILWIND.  AS HE WAS LANDING, THE ACFT VEERED RIGHT.  THE PLT OVERCORRECTED TO THE LEFT & THE PLANE TURNED SHARPLY LEFT, THEN THE RIGHT WING STRUCK THE GROUND & WAS DAMAGED.

## Aircraft

- Registration: [N4137Z](https://openairdocs.org/aircraft/N4137Z), registered now, S/N 18-8209, built 1964 (OpenAirDocs)
- Reported make and model: PIPER PA-18-150
- Registry model: [Piper PA-18-150](https://openairdocs.org/model/piper-pa-18-150) (registry code 7101828) (OpenAirDocs)
- Registry engine: [Lycoming O&VO-360 series](https://openairdocs.org/engine/lycoming-o-vo-360-series) (registry code 41514, reciprocating) (OpenAirDocs)
- Category: Airplane
- Serial number: 18-8209
- Engines: LYCOMING O-320-A2A 150 horsepower reciprocating
- Damage: Substantial damage
- Flight: Part 91
- Operator: Lavern D. St Clair, doing business as Val Air Soaring
- Departed: CD82
- Destination: CD82
- Airport: CD82, Val Air, runway 36, 3,100 × 100 ft, grass/turf

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 63; commercial; airplane ratings: single-engine land; instrument ratings: airplane; medical: class 1, valid medical--w/ waivers/lim; flight hours: 4,658 total, 118 in this make and model, 4,400 as pilot in command, 4 in the last 90 days, 3 in the last 30 days, 1 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Wind: 120° 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 19890626017589A](https://openairdocs.org/incident/19890626017589A), Jun 26, 1989: Piper PA18150, Durango, CO, Substantial damage. Landing after glider tow,lost directional control and ground looped.

## Other investigations on N4137Z (1)

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.

- [NTSB DEN67D0022](https://openairdocs.org/ntsb/DEN67D0022), Jul 1, 1966: Piper PA-18 (N4137Z), Byers, CO, substantial damage

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.

---
OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. Source documents are U.S. government works in the public domain.