# NTSB SEA98LA021: Enstrom F-28F, N171HH, John Day, OR, December 6, 1997 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: December 6, 1997, 14:00 local (22:00 UTC) - Place: John Day, OR - Coordinates: 44.420661, -118.93962 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=44.4207&lon=-118.9396&mi=10 - Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping) - Highest injury: No injuries - Injuries: 1 uninjured - Status: Completed, report May 4, 1998 - Report: Approved by Office Director - NTSB case key (mKey): 42743 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=SEA98LA021 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/42743/pdf - Page: https://openairdocs.org/ntsb/SEA98LA021 ## Probable cause a loss of engine power for undetermined reasons. ## Analysis The pilot reported that he was maneuvering with a full seed bucket to the work area when he noticed some rotor droop. The pilot stated that he lowered the collective and twisted on some more throttle to get the rpm back, however, nothing happened and the throttle hit the stop. The pilot initiated a forced landing and slowed the forward speed. The seed bucket swung forward and the helicopter landed on top of the bucket. The helicopter bounced twice and subsequently came to rest on its left side. Postaccident investigation of the engine revealed that the engine was in a condition for a test run. The engine was started and run for five to ten minutes without any noted problems before it was shut down. Further inspection of the wreckage did not reveal any evidence of a mechanical failure or malfunction. ## Factual narrative On December 6, 1997, about 1400 Pacific standard time, N171HH, an Enstrom F-28F helicopter, operated by the owner/pilot, impacted terrain during a forced landing near John Day, Oregon, and was substantially damaged. The forced landing was precipitated by a loss of engine power while manuevering. The airline transport pilot, the sole occupant, was not injured. Visual meteorological conditions prevailed and no flight plan had been filed. The aerial application flight departed from John Day about one hour prior to the accident and was conducted under 14 CFR Part 137. In a written statement, the pilot reported that he had just returned from seeding about 20 acres, and landed to refill the seed bucket. The pilot stated that after the bucket was filled, he lifted off and headed downhill towards the working area. The pilot stated that he "noticed some rotor droop and lowered the collective and twisted on some more throttle to get the rpm back." The pilot stated that nothing happened and the "throttle hit the stop." The pilot stated that he was aware that he was going to impact the terrain and slowed the forward speed. The seed bucket swung forward and the helicopter landed on top of the bucket. The helicopter bounced twice downhill and subsequently came to rest on its left side. Two Federal Aviation Administration (FAA) aviation safety inspectors from the Portland Flight Standards District Office, Hillsboro, Oregon, inspected the engine. The inspectors reported that the engine was prepared for a test run. After the preparation, the engine was started and ran for about five to ten minutes without any noted problems before it was shut down. Fuel samples were taken and filters were checked with no contaminants found. The fuel mixture was checked and found okay. Control continuity was established throughout the aircraft. The pilot provided his calculations for the weight of the helicopter at the time of the accident. The calculations indicated that the helicopter's weight was approximately 76 pounds under the maximum gross weight of 2,600 pounds. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Loss of engine power, maneuvering - aerial application - reason for occurrence undetermined (cause) - Forced landing, emergency descent/landing ## Aircraft - Registration: [N171HH](https://openairdocs.org/aircraft/N171HH), registered now, S/N 758, built 1988 (OpenAirDocs) - Reported make and model: Enstrom F-28F - Registry model: [Enstrom F-28F](https://openairdocs.org/model/enstrom-f-28f) (registry code 3300412) (OpenAirDocs) - Registry engine: [Lycoming HIO-360 series](https://openairdocs.org/engine/lycoming-hio-360-series) (registry code 41524, reciprocating) (OpenAirDocs) - Category: Helicopter - Serial number: 730 - Airframe hours: 1400 - Engines: Lycoming HIO-360-F1AD 225 horsepower reciprocating - Damage: Substantial damage - Flight: Aerial application, Part 137 - Registered owner: Stanley G. Hermens - Airworthiness certificate: Standard, Normal - Departed: 5J0, OR ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 54; airline transport, commercial; airplane ratings: single-engine sea, single-engine land, multi-engine land; instrument ratings: airplane; medical: class 2, valid medical--w/ waivers/lim; seat: left; flight hours: 16,000 total, 400 in this make and model ## Weather - Conditions: Visual (VMC), Day - Wind: 90° at 2 knots - Visibility: 25 statute miles - Lowest ceiling: none - Temperature: 48 °F, dew point 43 °F - Altimeter: 29.00 inHg - Observed at: 5J0, 15 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 19971206037439A](https://openairdocs.org/incident/19971206037439A), Dec 6, 1997: Enstrm F28F, John Day, OR, Substantial damage. On December 6, 1997, about 1400 pacific standard time, N171HH, an Enstrom F-28F helicoper, operated by the owner/pilot, impacted terrain during a forced… ## Other investigations on N171HH (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 SEA98FA055](https://openairdocs.org/ntsb/SEA98FA055), Mar 30, 1998: Enstrom F28F (N171HH), Baker, OR, substantial damage. Probable cause: Fatigue failure of the steel tubing pylon structure. Factors include inadequate inspection by maintenance personnel of damage after a previous accident. 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.