# NTSB LAX00TA006: McDonnell Douglas 369E, N991SD, Moreno Valley, CA, October 8, 1999 - Type: NTSB accident investigation - Classification: Accident · No injuries · Final report - Date: October 7, 1999, 20:05 local (Oct 8, 1999, 03:05 UTC) - Place: Moreno Valley, CA - Location: 33.9375° N, 117.2306° W: Placed by OpenAirDocs: center of Moreno Valley, CA, within about 6 miles (OpenAirDocs) - Nearby events: https://openairdocs.org/map.md?lat=33.9375&lon=-117.2306&mi=10 - Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping) - Highest injury: No injuries - Injuries: 3 uninjured - Status: Completed, report April 25, 2001 - Report: Approved by Office Director - NTSB case key (mKey): 47553 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=LAX00TA006 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/47553/pdf - Page: https://openairdocs.org/ntsb/LAX00TA006 ## Probable cause The failure of the pilot to maintain sufficient forward airspeed to preclude an inadvertent encounter with loss of tail rotor effectiveness, which resulted in a loss of yaw control. The pilot's failure to initiate timely remedial action is a factor. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Loss of control - in flight, maneuvering - weather condition - unfavorable wind - airspeed - inadequate, pilot in command (cause) - translational lift - not maintained, pilot in command (cause) - loss of tail rotor effectiveness - encountered - remedial action - delayed, pilot in command (contributing factor) - In flight collision with terrain/water, descent - uncontrolled - terrain condition - open field ## Analysis The Sheriff's Department helicopter was orbiting over ground based law enforcement activity. It was a dark night and the winds aloft were 20 to 25 knots at 500 feet agl. The pilot said he was attempting to shine the helicopter's spotlight on a vehicle; however, the wind kept blowing the helicopter past the location on each of the first two orbits. On the third orbit, the pilot inadvertently allowed the helicopter to slow below translational lift speed and the helicopter yawed 180 degrees to the right uncontrollably. The pilot momentarily recovered directional control of the helicopter but then the right yaw resumed. He made several more attempts to recover directional control of the helicopter but when he saw the altitude becoming low, he flew to a pre-selected landing zone where the helicopter landed hard while in a right yawing spin. During the landing the main rotor blades severed the tail boom and the helicopter came to rest on its right side. ## Factual narrative On October 7, 1999, at 2005 hours Pacific daylight time, a McDonnell Douglas 369E helicopter, N991SD, was substantially damaged during a forced landing at Moreno Valley, California, following an in-flight loss of directional control. The commercial pilot and two observer crewmembers were not injured. The helicopter was operated by the Riverside County Sheriff's Department under the provisions of 14 CFR Part 91 as a public-use aircraft. Visual meteorological conditions prevailed and no flight plan was filed for the local area patrol flight, which originated from Hemet, California, at 1950. According to the Sheriff's Department report, it was a dark night and the winds aloft were northerly at 20 to 25 knots, at 500 feet agl, as the pilot orbited over ground based law enforcement activity. In accordance with department operating procedures, the pilot had identified a school athletic field as a suitable emergency landing site. He was attempting to shine the helicopter's spotlight on a vehicle; however, the northerly wind kept blowing the aircraft well south of the location on each of the first two orbits. On the third orbit, he inadvertently allowed the helicopter to slow below translational lift speed and the helicopter yawed 180 degrees to the right uncontrollably. The pilot momentarily recovered directional control of the helicopter but then the right yaw resumed. He made several more attempts to recover directional control of the helicopter but when he saw the altitude becoming low, he flew to the pre-selected landing zone where the helicopter landed hard while in a right yawing spin. During the landing the main rotor blades severed the tail boom and the helicopter came to rest on its right side. ## Aircraft - Registration: N991SD (not matched to a registry record) - Reported make and model: McDonnell Douglas 369E - Category: Helicopter - Serial number: 500E - Airframe hours: 5474 - Engines: Allison 250C20B 420 horsepower turbo shaft - Damage: Substantial damage - Flight: Public aircraft, Part 91 - Registered owner: Riverside Co. Sheriff'S Dept - Airworthiness certificate: Standard, Normal - Last inspection: 100 hour, September 1, 1999, 30 hours before - Departed: HMT, HEMET, CA ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 41; commercial; airplane ratings: single-engine land, multi-engine land; instrument ratings: airplane, helicopter; medical: class 2, valid medical--no waivers/lim.; seat: left; flight hours: 2,737 total, 94 in this make and model, 2,153 as pilot in command, 174 in the last 90 days, 51 in the last 30 days, 6 in the last 24 hours ## Weather - Conditions: Visual (VMC), Night/dark - Wind: 340° at 9 knots - Visibility: 35 statute miles - Lowest ceiling: none - Temperature: 77 °F, dew point 28 °F - Altimeter: 29.00 inHg - Observed at: RIV, 1 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 19991007028609A](https://openairdocs.org/incident/19991007028609A), Oct 7, 1999: Hughes 369E, Moreno Valley, CA, Substantial damage. (.19) On October 7, 1999, at 2005 hours pacific daylight time, a Mcdonnell Douglas 369E, helicopter, N991SD, was substantially damaged during an emergency… 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.