# NTSB DEN99LA172: Piper PA-18-150, N3799Z, Telluride, CO, September 30, 1999 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: September 30, 1999, 11:30 local (17:30 UTC) - Place: Telluride, CO - Coordinates: 37.939731, -107.899185 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=37.9397&lon=-107.8992&mi=10 - Phase of flight: [Landing](https://openairdocs.org/ntsb-phases/550) (OpenAirDocs' grouping) - Highest injury: No injuries - Injuries: 2 uninjured - Status: Completed, report December 4, 2000 - Report: Approved by Office Director - NTSB case key (mKey): 47475 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=DEN99LA172 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/47475/pdf - Page: https://openairdocs.org/ntsb/DEN99LA172 ## Probable cause An encounter with a sudden tailwind gust windshift during landing roll, resulting in an inadvertent ground loop. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - On ground/water encounter with weather, landing - roll - weather condition - tailwind (cause) - weather condition - gusts (cause) - weather condition - sudden windshift (cause) - On ground/water encounter with terrain/water, landing - roll - airport facilities,runway/landing area condition - runway - ground loop/swerve - inadvertent, pilot in command ## Analysis Prior to takeoff from Montrose, Colorado, the pilot called Telluride airport, located 33.3 nm to the south, and asked an airport employee what the weather conditions were. He was advised the wind was calm. Prior to landing at Telluride, he listened to the airport's ASOS, and again the wind was calm. He then confirmed that with the airport's windsock. Touchdown and initial rollout on runway 09 were normal; however, after the aircraft's tail was lowered onto the runway, the airplane encountered a tailwind gust and ground looped. When the pilot exited the aircraft, he noted that the winds were out of the west. There is no recorded weather reporting facility at Telluride airport. The closest weather facility is located at Montrose. At 1053, the winds were reported from 290 degrees at 6 knots. According to the FAA's Airport/Facility Directory, all landings at Telluride should be performed on runway 09 to avoid populated areas. ## Factual narrative On September 30, 1999, approximately 1130 mountain daylight time, a Piper PA-18-150, N3799Z, was substantially damaged when it collided with terrain during landing roll at Telluride Regional Airport, Telluride, Colorado. The private pilot and one passenger were not injured. Visual meteorological conditions prevailed, and no flight plan had been filed for the personal cross-country flight being conducted under Title 14 CFR Part 91. The aircraft departed Montrose Regional Airport, Montrose, Colorado, at 1100. According to the pilot, prior to takeoff from Montrose, he called Telluride airport and asked an airport employee what the weather conditions were. He was told that the wind was calm. Prior to entering the traffic pattern for landing at Telluride, he listened to the airport's Automated Surface Observation System (ASOS), and again the wind was reported as calm. He then confirmed that with the airport's windsock. The Federal Aviation Administration's Airport/Facility Directory (Southwest U.S.) states that all takeoffs at Telluride are recommended to be conducted on runway 27, and all landings should be performed on runway 09 to avoid populated areas. The pilot stated that touchdown and initial rollout on runway 09 were "normal." However, after the tail was lowered onto the runway, the aircraft encountered a tailwind gust and ground looped. The airplane sustained damage to the right wing and right landing gear. When the pilot exited the aircraft, he noted that the winds were out of the west. There is no manual weather observation facility at Telluride airport. The closest weather facility is located at Montrose, located 33.3 nm to the north. At 1053, the winds at Montrose were reported from 290 degrees at 6 knots. The next weather record was at 1353, with winds variable at 4 knots. ## Aircraft - Registration: [N3799Z](https://openairdocs.org/aircraft/N3799Z), registered now, S/N 18-7495, built 1960 (OpenAirDocs) - Reported make and model: Piper PA-18-150 - Registry model: [Piper PA-18-150](https://openairdocs.org/model/piper-pa-18-150) (registry code 7101828) (OpenAirDocs) - Registry engine: [Lycoming 0-320 series](https://openairdocs.org/engine/lycoming-0-320-series) (registry code 41508, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 18-4795 - Airframe hours: 1076 - Engines: Lycoming O-320 150 horsepower reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Operator: Blake C. Freeland - Registered owner: Paul Engbring - Airworthiness certificate: Standard, Normal - Last inspection: Annual, September 14, 1999, 3 hours before - Departed: MTJ, MONTROSE, CO - Destination: TEX - Airport: TEX, Telluride Regional, runway 9, 6,870 × 100 ft, asphalt ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 45; private; airplane ratings: single-engine land; medical: class 3, valid medical--no waivers/lim.; seat: front; flight hours: 350 total, 47 in this make and model, 325 as pilot in command, 9 in the last 90 days, 4 in the last 30 days, 1 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 290° at 6 knots - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 57 °F, dew point 19 °F - Altimeter: 30.00 inHg - Observed at: MTJ, 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 19990930030939A](https://openairdocs.org/incident/19990930030939A), Sep 30, 1999: Piper PA18150, Telluride, CO, Substantial damage. (.19) On September 30, 1999, approximately 1130 mountain daylight time, a Piper PA-18-150, N3799Z, was substantially damaged when it collided with terrain… 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.