# NTSB LAX99LA112: Enstrom F-28F, N5700C, San Jose, CA, February 27, 1999 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: February 27, 1999, 12:56 local (20:56 UTC) - Place: San Jose, CA - Coordinates: 37.330921, -121.769676 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=37.3309&lon=-121.7697&mi=10 - Phase of flight: [Takeoff](https://openairdocs.org/ntsb-phases/300) (OpenAirDocs' grouping) - Highest injury: No injuries - Injuries: 2 uninjured - Status: Completed, report November 30, 2000 - Report: Approved by Office Director - NTSB case key (mKey): 45854 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=LAX99LA112 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/45854/pdf - Page: https://openairdocs.org/ntsb/LAX99LA112 ## Probable cause The loss of aircraft control due to the pilot's sudden application of collective combined with excessive cyclic inputs. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Loss of control - in flight, takeoff - aircraft control - not maintained, pilot in command (cause) - collective - excessive, pilot in command (cause) - cyclic - excessive, pilot in command (cause) - Roll over, takeoff ## Analysis The pilot and a mechanic were performing a postmaintenance test flight following tracking of the main rotor blades. One test flight had already been accomplished with no discrepancies. The pilot had not flown the helicopter during the preceding 90 days. As the pilot pulled the collective, the aircraft suddenly came to a 4-foot hover with the fuselage swinging side to side and fore and aft below the main rotor. The pilot attempted to recover; however, the aircraft pitched forward, the main rotor blades struck the ground, and the aircraft rolled onto its right side. The pilot said he thought he might have mispositioned the cyclic before raising the collective as he was attempting to comply with the mechanic's request to 'pull-off before vibration became a problem.' He said the controls 'felt' differently than he had expected. A detailed control system inspection found no evidence of preexisting discrepancies. ## Factual narrative On February 27, 1999, at 1256 hours Pacific standard time, an Enstrom F-28F, N5700C, rolled over and crashed during takeoff from the Reid-Hillview Airport, San Jose, California. The aircraft sustained substantial damage. The commercial pilot, who holds private helicopter privileges, and the mechanic were not injured. The aircraft was operated as a maintenance test flight by California In Nice Air, Inc., under 14 CFR Part 91 of Federal Aviation Regulations, and was originating when the accident occurred. Visual meteorological conditions prevailed at the time and no flight plan was filed. The pilot stated that he was in the left seat, applying collective in preparation to liftoff from the pad. As he pulled collective, the aircraft suddenly rose vertically to a height of 4 feet agl. He was surprised because he did not feel at the time that the aircraft had become light enough to hover. As the aircraft ascended, the fuselage began a left and right pendular motion, which then shifted to fore and aft movement as he attempted to recover. As the aircraft pitched forward for the final time, the main rotor blades struck the ground. After the rotor blades struck the ground, the aircraft rolled onto its right side before coming to rest. The pilot exited the aircraft without assistance. The mechanic shut off the master and fuel switches before being assisted through the broken windscreen by several nearby witnesses to the accident. The pilot stated that he has about 147.8 hours in helicopters and 110.3 hours in the F-28F, but had not flown the aircraft in the preceding 90 days. He said he thought he might have initially mispositioned the cyclic before raising the collective, but was also attempting to comply with the mechanic's request to "pull-off before vibration became a problem." He did not clearly recall what occurred or what control inputs he made after becoming airborne. He also did not remember making any sudden or abrupt control movements, but said the controls "felt" differently than he had expected. The mechanic had removed the right cyclic and pedal controls prior to flight. The mechanic, who occupied the right seat, reported the flight was being conducted to verify the main rotor tracking and balancing that had been completed earlier. The aircraft had already been test flown once since the tracking and balancing were completed with no reported abnormalities. The mechanic said there were three targets installed on each main rotor blade and a magnetic pickup on the main rotor mast. Also installed at the time was the associated wiring that connected the Strobex and Chadwick test equipment located in the rear of the aircraft. A Federal Aviation Administration airworthiness inspector checked the aircraft flight controls after the accident and reported that there was no evidence of any preexisting mechanical defects. ## Aircraft - Registration: [N5700C](https://openairdocs.org/deregistered/N5700C-2000-02-24), registration cancelled 2000-02-24, S/N 514 (OpenAirDocs) - Reported make and model: Enstrom F-28F - Registry model: [Enstrom F-28F](https://openairdocs.org/model/enstrom-f-28f) (registry code 3300412) (OpenAirDocs) - Category: Helicopter - Serial number: 514 - Airframe hours: 2335 - Engines: Lycoming HIO-360-F1AD 190 horsepower reciprocating - Damage: Substantial damage - Flight: Part 91 - Registered owner: Hiro Takai - Airworthiness certificate: Standard, Normal - Last inspection: Annual, February 23, 1999, 2 hours before - Departed: RHV - Airport: RHV, Reid-Hillview Of Santa Cl ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 47; private, commercial; airplane ratings: single-engine land, multi-engine land; instrument ratings: airplane; medical: class 3, valid medical--w/ waivers/lim; seat: left; flight hours: 536 total, 110 in this make and model, 446 as pilot in command, 5 in the last 90 days, 1 in the last 30 days ## Weather - Conditions: Visual (VMC), Day - Wind: 310° at 8 knots - Visibility: 15 statute miles - Lowest ceiling: 20,000 ft broken - Temperature: 66 °F, dew point 39 °F - Altimeter: 30.00 inHg - Observed at: SJC, 5 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 19990227042349A](https://openairdocs.org/incident/19990227042349A), Feb 27, 1999: Enstrm F28F, San Jose, CA, Substantial damage. (.4)The pilot and a mechanic were performing a postmaintenance test flight following tracking of the main rotor blades. One test flight had already been… 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.