# NTSB DEN01LA087: Mooney M20K, N921Z, Bountiful, UT, April 17, 2001 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: April 16, 2001, 18:00 local (Apr 17, 2001, 00:00 UTC) - Place: Bountiful, UT - Location: 40.8681° N, 111.9275° W: Placed by OpenAirDocs at SKYPARK (BTF), within about a mile (OpenAirDocs) - Nearby events: https://openairdocs.org/map.md?lat=40.8681&lon=-111.9275&mi=10 - Phase of flight: [Landing](https://openairdocs.org/ntsb-phases/550) (OpenAirDocs' grouping) - Highest injury: No injuries - Injuries: 4 uninjured - Status: Completed, report July 25, 2002 - Report: Approved by Office Director - Parties: FAA-- Flight Standards District Office - NTSB case key (mKey): 52087 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=DEN01LA087 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/52087/pdf - Page: https://openairdocs.org/ntsb/DEN01LA087 ## Probable cause the failure of the airplane's electrical system for an undetermined reason, which resulted in the collapse of the left main gear on landing. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Airframe/component/system failure/malfunction, landing - roll - electrical system - failure (cause) - Main gear collapsed, landing - roll - On ground/water collision with object, landing - roll - object - sign ## Analysis The pilot departed for a cross-country flight. Soon after departure, his electrical system failed. The pilot returned to the departure field, and initiated a precautionary landing. Upon landing, the left main landing gear failed, and the airplane skidded off the runway and struck a sign post. ## Factual narrative On April 16, 2001, at approximately 1800 mountain daylight time, a Mooney M20K, N921Z, was substantially damaged when the left main landing gear collapsed on landing at Skypark Airport, Bountiful, Utah. The commercial pilot and his three passengers were not injured. The airplane was being operated by the pilot under Title 14 CFR Part 91. Visual meteorological conditions prevailed for the local flight which originated at 1735. No flight plan had been filed. According to the pilot's written statement, he departed runway 34 en route to Hailey, Idaho. Shortly after takeoff, he radioed Salt Lake City approach to request transition through class B airspace. Permission was granted and he was told to squawk 0306. He set the transponder to the given code and pressed the ident button. He was not "picked up" by approach so he repeated the process. After 2 to 3 minutes, the pilot said he "lost all electrical power." The pilot said, "I checked buses, recycled master and electrical system checked." He headed back to the airport and lowered the landing gear manually. He asked ground personnel to look to see if the landing gear was extended during a low pass, and they replied that it was. The pilot heard "pops in headset" so the master switch was kept off during landing. Upon landing, the left main landing gear collapsed, and the airplane skidded off the runway into a grass area. The right wing struck a sign post, which damaged the leading edge of the wing, and the fuselage was twisted near the empennage. ## Aircraft - Registration: [N921Z](https://openairdocs.org/aircraft/N921Z), registered now, S/N 251079, built 1986 (OpenAirDocs) - Reported make and model: Mooney M20K - Registry model: [Mooney M20K](https://openairdocs.org/model/mooney-m20k) (registry code 5870220) (OpenAirDocs) - Registry engine: [Continental TSIO-520 series](https://openairdocs.org/engine/continental-tsio-520-series) (registry code 17040, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 25-1079 - Airframe hours: 3133 - Engines: Continental TSIO 520 NB 305 horsepower reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Registered owner: International Aviation Corp - Airworthiness certificate: Standard, Normal - Last inspection: Annual, September 15, 2000, 19 hours before - Departed: BTF, Bountiful, UT - Destination: BTF, Bountiful, UT - Airport: BTF, Skypark, runway 34, 5,250 × 70 ft, asphalt ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 63; injuries: none; commercial; airplane ratings: multi-engine land, single-engine land; instrument ratings: airplane; medical: class 2, valid medical--w/ waivers/lim; last flight review October 18, 2000; seat: left; flight hours: 1,917 total, 200 in this make and model, 17 in the last 90 days, 17 in the last 30 days, 1 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 340° at 9 knots - Visibility: 10 statute miles - Lowest ceiling: 25,000 ft broken - Temperature: 66 °F, dew point 37 °F - Altimeter: 30.05 inHg - Observed at: SLC, 8 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 20010416006459A](https://openairdocs.org/incident/20010416006459A), Apr 16, 2001: Mooney M20K, Bountiful, UT, No damage. (-23) A/c lost all electrical power approx. 10 minutes after departure frombtf airport. Pilot made an emergency return to airport. Initial investigation… 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.