# NTSB NYC88LA018: Enstrom F-28C, N51699, Laconia, NH, October 25, 1987

- Type: NTSB accident investigation
- Classification: Accident · No injuries · Limited investigation · Final report
- Date: October 25, 1987, 16:25 local (21:25 UTC)
- Place: Laconia, NH
- Location: 43.5730° N, 71.4178° W: Placed by OpenAirDocs at LACONIA MUNI (LCI), within about a mile (OpenAirDocs)
- Nearby events: https://openairdocs.org/map.md?lat=43.5730&lon=-71.4178&mi=10
- Phase of flight: [Landing](https://openairdocs.org/ntsb-phases/550) (OpenAirDocs' grouping)
- Highest injury: No injuries
- Injuries: 3 uninjured
- Status: Completed, report June 7, 1989
- Report: Approved by Office Director
- NTSB case key (mKey): 36043
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=NYC88LA018
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/36043/pdf
- Page: https://openairdocs.org/ntsb/NYC88LA018

## Sequence of events

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

- Miscellaneous/other, landing - flare/touchdown
  - planning/decision - improper, pilot in command (cause)
  - emergency procedure - simulated, pilot in command
  - autorotation - performed, pilot in command
  - rotor rpm - not maintained, pilot in command
  - weather condition - unfavorable wind (contributing factor)
  - collective - improper use of, pilot in command (cause)

## Analysis

THE PLT RPRTD HE WAS DEMONSTRATING A FULL TOUCHDOWN AUTOROTATION IN WINDS THAT WERE FROM 290 DEG AT 15 GUSTING 20 KTS. HE STATED THE TOUCHDOWN WAS SOFT WITH A LOT OF PITCH PULLED IN; HOWEVER, AS HE LOWERED THE COLLECTIVE AFTER TOUCHDOWN, THE RETREATING BLADE FLEXED DOWNWARD & SEVERED THE AFT PORTION OF THE TAIL BOOM & THE TAIL ROTOR DRIVE SHAFT. THE PLT BELIEVED HE HAD LOWERED THE COLLECTIVE TOO FAST AFTER TOUCHDOWN, WHICH WOULD HAVE ALLOWED THE BLADES TO FLAP DOWNWARD. ALSO, HE BELIEVED THE HIGH WIND & REDUCED RPM FROM THE AUTOROTATION WOULD HAVE ATTRIBUTED TO EXCESSIVE FLAPPING OF THE RETREATING ROTOR BLADES.

## Aircraft

- Registration: [N51699](https://openairdocs.org/aircraft/N51699), registered now, S/N 416, built 1977 (OpenAirDocs)
- Reported make and model: ENSTROM F-28C
- Registry model: [Enstrom F-28C](https://openairdocs.org/model/enstrom-f-28c) (registry code 3300407) (OpenAirDocs)
- Registry engine: [Lycoming HIO-360 series](https://openairdocs.org/engine/lycoming-hio-360-series) (registry code 41524, reciprocating) (OpenAirDocs)
- Category: Helicopter
- Serial number: 416
- Airframe hours: 2753
- Engines: LYCOMING HIO-360-E1AD 205 horsepower reciprocating
- Damage: Substantial damage
- Flight: Personal, Part 91
- Registered owner: Copters Unlimited, Inc.
- Airworthiness certificate: Standard, Normal
- Last inspection: 100 hour, October 8, 1987
- Departed: LCI
- Airport: LCI, Laconia

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 38; commercial, flight instructor; airplane ratings: single-engine land; medical: class 2, valid medical--no waivers/lim.; seat: left; flight hours: 666 total, 435 in this make and model, 591 as pilot in command, 232 in the last 90 days, 4 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Wind: 290° at 15 knots, gusting 20
- Visibility: 20 statute miles
- Lowest ceiling: none
- Temperature: 48 °F
- Altimeter: 30.00 inHg

## 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 19871025060549A](https://openairdocs.org/incident/19871025060549A), Oct 25, 1987: Enstrm F28C, Laconia, NH, Substantial damage. On a full touchdown autorotation, lowered collective and rotor speed. Allowed blade to flex and severed tailboom.

## Other investigations on N51699 (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 CHI03LA217](https://openairdocs.org/ntsb/CHI03LA217), Jul 20, 2003: Enstrom F-28C (N51699), Waverly, IA, substantial damage. Probable cause: The main rotor blade push-pull rods being corroded, sustaining fatigue, and separating in cruise and the main rotor blade contacting the tail boom during the emergency landing. Factors were the…

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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