# NTSB LAX03LA235: Robinson R44, N8329B, Happy Jack, AZ, July 17, 2003 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: July 17, 2003, 13:05 local (20:05 UTC) - Place: Happy Jack, AZ - Coordinates: 34.828056, -111.188888 - Nearby events: https://openairdocs.org/map.md?lat=34.8281&lon=-111.1889&mi=10 - Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping) - Highest injury: No injuries - Injuries: 2 uninjured - Status: Completed, report October 27, 2005 - Report: Approved by Office Director - Parties: Federal Aviation Administration Scottsdale FSDO - NTSB case key (mKey): 57511 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=LAX03LA235 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/57511/pdf - Page: https://openairdocs.org/ntsb/LAX03LA235 ## Probable cause the partial loss of engine power due to an excessively lean mixture for undetermined reasons during cruise flight. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Loss of engine power(partial) - nonmechanical, cruise - normal - reason for occurrence undetermined - fuel system - blocked(partial) (cause) - Forced landing, descent - emergency - autorotation - performed, pilot in command - In flight collision with terrain/water, landing - flare/touchdown - terrain condition - high vegetation ## Analysis The engine lost power during cruise flight, and the helicopter collided with high vegetation during an autorotative descent. Just before touchdown during the forced landing, engine power was restored; however, the pilot decided to concentrate on successfully completing the forced landing. The helicopter touched down in high vegetation and was substantially damaged. The power loss was not preceded by any auditory or visual warnings, and none occurred during the descent. Following recovery of the helicopter from the remote site, the engine was visually examined then placed into a test cell and run up. During the first engine run, the engine exhibited the following results: (1) normal start; (2) normal warm-up; (3) lean operation upon accelerating between 2,250 and 2,300 rpm with no fuel boost pump on; (4) upon turning on the test cell's fuel boost pump, the engine accelerated between 2,700 and 2,800 rpm with no hesitation. During the second engine run, with a carburetor from another Lycoming O-540 engine, the accident engine operated normally during run up to full power without the test cell's fuel boost pump turned on. Thereafter, the accident carburetor was examined, including a flow bench test, and no abnormalities were found that would have prevented the carburetor from functioning within prescribed design specifications. The reason for the excessively lean mixture/restricted fuel flow, which reduced the engine's available power, was not ascertained. ## Factual narrative On July 17, 2003, about 1305 mountain standard time, a Robinson R44, N8329B, experienced a total loss of engine power while cruising about 12 miles northeast of Happy Jack, Arizona. The private pilot performed an autorotative descent into the underlying rough terrain. During the descent, just before touchdown, the pilot was able to restart the engine. The pilot reported that, at the time of the restart, he needed to concentrate on performing the forced landing to avoid rolling down the underlying hill. During the landing sequence, the helicopter collided with high vegetation and was substantially damaged. Neither the private pilot nor the passenger was injured. Visual meteorological conditions prevailed at the time of the personal flight, and no flight plan was filed. The helicopter was owned and operated by the pilot. The flight was performed under the provisions of 14 CFR Part 91, and it originated from Flagstaff, Arizona, about 1245. The pilot subsequently reported to the National Transportation Safety Board investigator that during the cruise flight the engine suddenly lost all power while cruising about 6,000 feet mean sea level. The power loss was not preceded by any auditory or visual warnings, and none occurred during the descent. The pilot stated that after the engine lost power he only concentrated on the autorotation. The helicopter wreckage was airlifted out of the remote accident site and was examined by the Federal Aviation Administration (FAA) coordinator. The helicopter's engine was placed into a test cell. The FAA reported that during the first engine run the engine exhibited the following results: (1) normal start; (2) normal warm-up; (3) lean operation upon accelerating between 2,250 and 2,300 rpm with no fuel boost pump on; (4) upon turning on the test cell's fuel boost pump, the engine accelerated between 2,700 and 2,800 rpm with no hesitation. The FAA additionally reported that during the second engine run, with a carburetor from another Lycoming O-540 engine, the accident engine operated normally during runup to full power without the test cell's fuel boost pump turned on. The accident Precision Airmotive Corporation carburetor, Model MA-4-5, part number 10-6035-11, serial number 75079404, was sent to its manufacturer for examination under the supervision of a Safety Board investigator. The examination, including a flow test, did not reveal any abnormalities that inhibited the carburetor from functioning within prescribed design specifications. The reason for the excessively lean mixture/restricted fuel flow, which reduced the engine's available power, was not ascertained. ## Aircraft - Registration: [N8329B](https://openairdocs.org/deregistered/N8329B-2003-12-24), registration cancelled 2003-12-24, S/N 0219, built 1995 (OpenAirDocs) - Reported make and model: Robinson R44 - Registry model: [Robinson Helicopter R44](https://openairdocs.org/model/robinson-helicopter-r44) (registry code 7640120) (OpenAirDocs) - Registry engine: [Lycoming 0-540 series](https://openairdocs.org/engine/lycoming-0-540-series) (registry code 41532, reciprocating) (OpenAirDocs) - Category: Helicopter - Serial number: 0219 - Airframe hours: 1800 - Engines: Lycoming O-540-F1B5 205 horsepower reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Registered owner: William R. Stokely - Airworthiness certificate: Standard, Normal - Last inspection: Annual, June 1, 2003 - Departed: FLG, Flagstaff, AZ - Destination: PAN, Payson, AZ ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 60; injuries: none; private; medical: class 2, with waivers/limitations; seat: right; flight hours: 9,000 total, 1,200 in this make and model ## Weather - Conditions: Visual (VMC), Day - Wind: 120° at 8 knots - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 88 °F, dew point 37 °F - Altimeter: 30.36 inHg - Observed at: FLG, 30 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 20030717016869A](https://openairdocs.org/incident/20030717016869A), Jul 17, 2003: Robsin R44, Flagstaff, AZ, Substantial damage. (-23) While cruising @ 900' (AGL) approx. 29 miles se of Flagstaff, AZ, heading to payson, AZ, the pilot lost power and entered autorotation. The helicopter… ## Other investigations on N8329B (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 CHI98LA239](https://openairdocs.org/ntsb/CHI98LA239), Jul 2, 1998: Robinson R-44 (N8329B), Cassville, MO, substantial damage. Probable cause: The pilot in command's inadequate preflight planning/preparation and weather evaluation that resulted in flight into adverse weather conditions. Factors to the accident were a preflight briefing… 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.