# NTSB NYC96LA167: Bell 206B, N9913K, Starks, ME, August 13, 1996 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: August 13, 1996, 12:40 local (16:40 UTC) - Place: Starks, ME - Location: 44.7306° N, 69.9662° W: Placed by OpenAirDocs: center of Starks, ME, within about 6 miles (OpenAirDocs) - Nearby events: https://openairdocs.org/map.md?lat=44.7306&lon=-69.9662&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 29, 1997 - Report: Approved by Office Director - NTSB case key (mKey): 39230 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=NYC96LA167 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/39230/pdf - Page: https://openairdocs.org/ntsb/NYC96LA167 ## Probable cause the pilot's improper decision to operate at slow airspeed, and close to the critical relative wind azimuth area in gusty, variable winds, which resulted in an inadvertent loss of tail rotor effectiveness. The gusty crosswind and lack of a suitable terrain for a landing were related factors. ## 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 - crosswind (contributing factor) - weather condition - gusts (contributing factor) - in-flight planning/decision - improper, pilot in command (cause) - loss of tail rotor effectiveness - inadvertent, pilot in command (cause) - In flight collision with object, descent - uncontrolled - autorotation - initiated, pilot in command - terrain condition - none suitable (contributing factor) - object - tree(s) ## Analysis The pilot was conducting a powerline patrol, and at the request of the observer(s), he maneuvered the helicopter so they could take another look at a tower. According to the pilot, he was flying west, and the wind was from the west to northwest at 10 knots with gusts from 15 to 20 knots. He inadvertently slowed to 20 knots. As the pilot applied power and left pedal, the helicopter started a right rotation. He was unable to recover directional control, and was forced to autorotate into unsuitable terrain. The tail rotor struck a tree during descent. During the landing, the skids were driven into the fuselage. According to a chart in the flight manual, the critical wind azimuth area was from 050 degrees to 210 degrees. ## Factual narrative On August 13, 1996, about 1240 eastern daylight time, a Bell 206-BII was substantially damaged when it struck the ground near Starks, Maine. The airline transport pilot and two passengers were not injured. Visual meteorological conditions prevailed and no flight plan had been filed for the power line observation flight which originated at Rangeley, Maine, about 1050 and was operated under 14 CFR Part 91. In the NTSB Accident Report, the pilot reported that he was flying to the west. He further stated: "...the observer spotted a problem with one of the structures and requested another look and asked for a slow pass. I turned downwind and set up to be on course into the wind at least three structures back from the support structure. The offset was 150-200 feet AGL up and to the left of the wires at 30 MPH so the observer, in the back, could get a good look." "I scanned the wires to maintain offset and then looked inside. Airspeed had decreased to 20 MPH and I raised collective and added left pedal. The aircraft yawed to the right and I continued to add left pedal until it hit the stop. As the nose of the aircraft went through the wind line I had full left pedal applied and the yaw rate continued to accelerate. I could not apply forward cyclic at that time because of a taller tree line to the south. After one rotation I decreased pedal input then reapplied it to try and get good air to the tail rotor." "The yaw rate continued to accelerate and the aircraft began to settle. I saw that the torque was jumping between 90 and 110%, the aircraft quit flying and began to settle into the power line right of way." "The tail boom/rotor impacted a tree, and the yaw rate continued to accelerate. Once I was sure we were in the right of way below the wires and away from the trees I executed an autorotation. The helicopter stayed upright, nose downhill, right skid up on a rock. The pax reported that they were OK with no injuries and a normal shutdown was completed...." In the NTSB Accident report, the pilot reported the winds were from the west/north west at 10 knots, with gusts at 15 to 20 knots. Page 3-6C of the FAA APPROVED 206B Flight Manual has chart which shows the critical wind angle as between 050 degrees, through 210 degrees. Page 3-6D of the FAA APPROVED 306B Flight Manual states: "...AREA A (white area as shown on the hover ceiling charts represents hover performance for which satisfactory stability and control has been demonstrated in relative winds of 17 knots (20 MPH) sideward and rearward at all loading conditions...." "...AREA B (yellow area) as shown on hover ceiling charts presents additional hover performance which can be realized in CALM WINDS or winds outside the CRITICAL RELATIVE WIND AZIMUTH AREA...." ## Aircraft - Registration: [N9913K](https://openairdocs.org/aircraft/N9913K), registered now, S/N 2055, built 1976 (OpenAirDocs) - Reported make and model: Bell 206B - Registry model: [Bell 206B](https://openairdocs.org/model/bell-206b) (registry code 1181511) (OpenAirDocs) - Registry engine: [Allison 250 SER 400HP](https://openairdocs.org/engine/allison-250-ser-400hp) (registry code 03013, turbo-shaft) (OpenAirDocs) - Category: Helicopter - Serial number: 2055 - Airframe hours: 7943 - Engines: Allison 250-C20B 400 horsepower turbo shaft - Damage: Substantial damage - Flight: Aerial observation, Part 91 - Registered owner: Maine Helicopters - Airworthiness certificate: Standard, Normal - Last inspection: 100 hour, June 25, 1996, 18 hours before - Departed: 8B0, RANGELEY, ME - Destination: 2B7, PITTSFIELD, ME ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 34; airline transport, commercial; airplane ratings: single-engine land; instrument ratings: airplane, helicopter; medical: class 1, valid medical--w/ waivers/lim; seat: right; flight hours: 3,289 total, 1,767 in this make and model, 2,174 as pilot in command, 45 in the last 90 days, 5 in the last 30 days, 4 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 270° at 10 knots, gusting 15 - Visibility: 10 statute miles - Lowest ceiling: none ## 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 19960813022649A](https://openairdocs.org/incident/19960813022649A), Aug 13, 1996: Bell 206B, Starks, ME, Substantial damage. Power line patrol. Flew slow downwind to observe spot. Got too slow. Lost tail rotor effect. Yawed. Tail hit trees. ## Other investigations on N9913K (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 ERA23LA307](https://openairdocs.org/ntsb/ERA23LA307), Jul 21, 2023: Bell 206 (N9913K), Terra Alta, WV, substantial damage. Probable cause: The pilot’s inability to maneuver the helicopter for recovery after experiencing a strong, unanticipated tailwind in a confined operating area, which resulted in a descent and subsequent impact with… 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.