# NTSB FTW97LA217: Bell 206L-3, N207DS, Weston, CO, June 12, 1997 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: June 12, 1997, 15:18 local (21:18 UTC) - Place: Weston, CO - Coordinates: 37.129142, -105.009346 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=37.1291&lon=-105.0093&mi=10 - Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping) - Highest injury: No injuries - Injuries: 5 uninjured - Status: Completed, report September 30, 1997 - Report: Approved by Office Director - NTSB case key (mKey): 20240 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=FTW97LA217 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/20240/pdf - Page: https://openairdocs.org/ntsb/FTW97LA217 ## Probable cause the pilot's improper in-flight planning/decision and failure to maintain adequate altitude and/or clearance from rising mountainous/hilly terrain. The unfavorable wind condition and low airspeed were related factors. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - In flight encounter with weather, maneuvering - weather condition - unfavorable wind (contributing factor) - weather condition - gusts (contributing factor) - In flight collision with object, maneuvering - in-flight planning/decision - improper, pilot in command (cause) - airspeed - low, pilot in command (contributing factor) - terrain condition - mountainous/hilly - altitude/clearance - not maintained, pilot in command (cause) ## Analysis The pilot said he crested a ridge and descended into the next valley following the terrain downhill. The wind felt like it was calm. As he approach the far side of the valley, the pilot realized he was going to have to make a 360 degree climbing turn in order to clear the ridge. Reportedly, after completing about 90 degrees of the turn, the helicopter was hit by a gust of wind from the rear, causing a 'significant decrease in apparent airspeed,' and the helicopter settled toward the trees. The pilot said he had to decide whether to attempt completing the turn and risk striking a tree with ground speed, or attempt a touchdown with zero airspeed. He chose the latter. The helicopter settled into trees and rolled over. ## Factual narrative On June 12, 1997, at 1518 mountain daylight time, a Bell 206L-3, N207DS, operated by Delta Bravo Sierra Corporation d/b/a DBS Air, Inc., was substantially damaged when it collided with trees while maneuvering 15 miles southwest of Weston, Colorado. The commercial pilot and four passengers escaped injury. Visual meteorological conditions prevailed, and a company VFR flight plan had been filed for the nonscheduled domestic passenger air taxi flight being conducted under Title 14 CFR Part 135. The flight originated from Trinidad, Colorado, on June 12, 1997, approximately 1405. According to the pilot's accident report, this was his fourth trip of the day over the same proposed gas pipeline route. The flight was for the purpose of conducting a raptor (bird) study, and required low and slow flight over wooded areas. The pilot noted convective clouds had been building all day. The pilot said he crested a ridge and descended into the next valley following the terrain downhill. "The wind felt like it was at a momentary lull," he wrote. "As we approached the far side of this particular valley (west side), it was obvious we were going to require a climbing 360 degree turn in order to clear the next ridge." After completing about 90 degrees of the turn, the helicopter was hit by a gust of wind from the rear, causing a "significant decrease in apparent airspeed" and the helicopter settled towards the trees. The pilot said he had to decide whether to attempt completing the turn and risk striking a tree with ground speed, or attempt a landing with zero airspeed. He chose the latter. The helicopter settled into trees and rolled over on its right side. ## Aircraft - Registration: [N207DS](https://openairdocs.org/deregistered/N207DS-2015-07-30), registration cancelled 2015-07-30, S/N 51546, built 1991 (OpenAirDocs) - Reported make and model: Bell 206L-3 - Registry model: [Bell 206L-3](https://openairdocs.org/model/bell-206l-3) (registry code 1182108) (OpenAirDocs) - Registry engine: [Allison 250-C30 series](https://openairdocs.org/engine/allison-250-c30-series) (registry code 03015, turbo-shaft) (OpenAirDocs) - Category: Helicopter - Serial number: 51253 - Airframe hours: 1692 - Engines: Allison 250-C30P 650 horsepower turbo shaft - Damage: Substantial damage - Flight: Part 135 - Registered owner: Delta Bravo Sierra Corp. - Airworthiness certificate: Standard, Normal - Last inspection: 100 hour, April 10, 1997, 38 hours before - Departed: TAD, TRINIDAD, CO - Flight plan: Company VFR ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 47; commercial; airplane ratings: single-engine land; instrument ratings: airplane; medical: class 2, valid medical--no waivers/lim.; seat: right; flight hours: 1,800 total, 699 in this make and model, 1,578 as pilot in command, 56 in the last 90 days, 36 in the last 30 days, 6 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 100° at 13 knots - Visibility: 10 statute miles - Lowest ceiling: 25,000 ft broken - Temperature: 77 °F, dew point 46 °F - Altimeter: 29.00 inHg - Observed at: TAD, 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 19970612013819A](https://openairdocs.org/incident/19970612013819A), Jun 12, 1997: Bell 206L3, Weston, CO, Substantial damage. Helicopter was involved in gas line survey when it lost altitude, crashed into trees. (.4)the pilot said he crested a ridge and descended into the next valley… ## Other investigations on N207DS (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 CEN14FA122](https://openairdocs.org/ntsb/CEN14FA122), Jan 27, 2014: Bell 206L 3 (N207DS), Silt, CO, destroyed, 3 fatal. Probable cause: The pilot’s inadequate preflight planning for a low-level aerial surveillance flight of power transmission lines, which led to his being unaware of the crossing power line while flying toward the sun… 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.