# NTSB MIA90LA120: Enstrom F-28A, N9056, Marathon, FL, May 13, 1990

- Type: NTSB accident investigation
- Classification: Accident · No injuries · Limited investigation · Final report
- Date: May 13, 1990, 11:30 local (15:30 UTC)
- Place: Marathon, FL
- Coordinates: 24.709184, -81.079994 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=24.7092&lon=-81.0800&mi=10
- Phase of flight: [Initial climb](https://openairdocs.org/ntsb-phases/350) (OpenAirDocs' grouping)
- Highest injury: No injuries
- Injuries: 3 uninjured
- Status: Completed, report September 21, 1992
- Report: Approved by Office Director
- NTSB case key (mKey): 32654
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=MIA90LA120
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/32654/pdf
- Page: https://openairdocs.org/ntsb/MIA90LA120

## Probable cause

FAILURE OF THE INPUT DRIVE GEAR OF THE TAIL ROTOR GEAR BOX FOR UNDETERMINED REASONS BECAUSE THE DRIVE GEAR WAS NOT RECOVERED FROM THE OCEAN.

## Sequence of events

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

- Airframe/component/system failure/malfunction, takeoff - initial climb
  - rotor drive system,tail rotor gearbox(90 deg) - undetermined
- Forced landing, descent - emergency
- In flight collision with terrain/water, descent - emergency
  - terrain condition - water

## Analysis

THE SIGHTSEEING HELICOPTERS HAD JUST TAKEN OFF AND WAS ABOUT 50 FT IN THE AIR WHEN TAIL ROTOR DRIVE AND CONTROL WAS LOST. THE PILOT EXECUTED A POWER ON FORCED LANDING TO THE OCEAN THE TAIL ROTOR GEAR BOX FAILED AT THE CASTING AROUND THE INPUT DRIVE GEAR AND THERE WERE SIGNS OF LOGJAMMING ON THE INTERIOR OF THE CASTING. THE DRIVE GEAR WAS NOT RECOVERED FROM THE OCEAN.

## Aircraft

- Registration: [N9056](https://openairdocs.org/deregistered/N9056-2012-08-10), registration cancelled 2012-08-10, S/N 167, built 1973 (OpenAirDocs)
- Reported make and model: ENSTROM F-28A
- Registry model: [Enstrom F-28A](https://openairdocs.org/model/enstrom-f-28a) (registry code 3300406) (OpenAirDocs)
- Registry engine: [Lycoming I0360 series](https://openairdocs.org/engine/lycoming-i0360-series) (registry code 41515, reciprocating) (OpenAirDocs)
- Category: Helicopter
- Serial number: 167
- Airframe hours: 834
- Engines: LYCOMING IO-360 205 horsepower reciprocating
- Damage: Substantial damage
- Flight: Part 91
- Registered owner: All Air Corporation
- Airworthiness certificate: Standard, Normal
- Last inspection: 100 hour, March 10, 1990, 20 hours before
- Departed: MARATHON, FL

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 62; commercial, flight instructor; medical: class 2, valid medical--no waivers/lim.; seat: left; flight hours: 2,300 total, 1,597 in this make and model, 2,174 as pilot in command, 16 in the last 90 days, 13 in the last 30 days, 3 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Wind: 50° at 8 knots
- Visibility: 7 statute miles
- Lowest ceiling: none
- Temperature: 81 °F, dew point -0 °F
- Altimeter: 29.00 inHg
- Observed at: MTH, 2 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 19900513018339A](https://openairdocs.org/incident/19900513018339A), May 13, 1990: Enstrm F28A, Marathon, FL, Substantial damage. Lost tail rotor control on climbout. Made power landing in ocean near shore. Tail rotor gear jammed.

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.