# NTSB DEN04IA014: Learjet 45, N420FX, Denver, CO, October 22, 2003 - Type: NTSB incident investigation - Classification: Incident · No injuries · Incident investigation · Final report - Date: October 22, 2003, 17:30 local (23:30 UTC) - Place: Denver, CO - Coordinates: 39.858612, -104.066947 - Nearby events: https://openairdocs.org/map.md?lat=39.8586&lon=-104.0669&mi=10 - Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping) - Highest injury: No injuries - Injuries: 4 uninjured - Status: Completed, report March 2, 2004 - Report: Approved by Office Director - Parties: Federal Aviation Administration - NTSB case key (mKey): 58239 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=DEN04IA014 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/58239/pdf - Page: https://openairdocs.org/ntsb/DEN04IA014 ## Probable cause the failure of the airplane's spoiler system when used as speed brakes due to high resistances in the spoilers' actuator coils. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Airframe/component/system failure/malfunction, descent - flt control syst,wing spoiler system - failure (cause) - emergency procedure - performed, flightcrew ## Analysis The airplane was descending through 13,000 feet when the captain extended both spoilers as speed brakes to reduce the airplane's speed. The left spoiler came up and the right spoiler barely moved, causing the airplane to roll to the left. The pilots saw the amber-colored "Spoiler Fail CAS" light illuminate. The captain retracted the spoilers, rolled the airplane back to a level attitude, and began running the appropriate emergency checklist. The captain continued the descent and landed uneventfully. An examination of the airplane showed high internal resistance in the left and right spoilers' actuator coils. No other anomalies were found. ## Factual narrative On October 22, 2003, at 1730 mountain daylight time, a Learjet 45, N420FX, owned by Bombardier Aerospace Flexjet and operated by Vestar Capital Partners, experienced an uncontrolled spoiler roll event during descent through 13,000 feet mean sea level, while en route to the Denver International Airport (DEN), Denver, Colorado. The flight crew regained control of the airplane, and made an uneventful landing at DEN. The airline transport pilot certificated captain, airline transport pilot certificated first officer, and 2 passengers on board the airplane were not injured. The personal domestic business flight was being conducted on an instrument flight rules flight plan from Teterburo, New Jersey, to DEN under the provisions of Title 14 CFR Part 91. Visual meteorological conditions prevailed at the time of the incident. The company reported that as the crew was descending through 13,000 feet, the captain extended both spoilers as speed brakes to reduce the airplane's speed. The left spoiler came up and the right spoiler barely moved, causing the airplane to roll to the left. The company also reported the pilots saw the amber-colored "Spoiler Fail CAS" light illuminate. The captain retracted the spoilers, rolled the airplane back to a level attitude, and began running the appropriate emergency checklist. The captain continued the descent and landed at DEN uneventfully. The left and right spoiler actuators (part number 6627602001-003) were ground tested at DEN. The tests showed high internal resistance in the actuator coils. The actuators were removed and retained for further examination. Later testing at the manufacturer in Wichita, Kansas, confirmed this finding. ## Aircraft - Registration: [N420FX](https://openairdocs.org/deregistered/N420FX-2008-01-10), registration cancelled 2008-01-10, S/N 126, built 2000 (OpenAirDocs) - Reported make and model: Learjet 45 - Registry model: [Learjet 45](https://openairdocs.org/model/learjet-45) (registry code 5170805) (OpenAirDocs) - Registry engine: [Honeywell TFE-731-SER series](https://openairdocs.org/engine/honeywell-tfe-731-ser-series) (registry code 33902, turbo-fan) (OpenAirDocs) - Category: Airplane - Serial number: 45-126 - Airframe hours: 2102 - Engines: Honeywell TFE-731-20AR 3650 lbs thrust turbo fan; Honeywell TFE-731-20AR 3650 lbs thrust turbo fan - Damage: No damage - Flight: Personal, Part 91 - Operator: Vestar Capital Partners, doing business as Bombardier Aerospace Flexjet - Registered owner: Bombardier Aerospace Flexjet - Airworthiness certificate: Standard, Normal - Departed: TEB, Teterburo, NJ - Destination: DEN, Denver, CA - Flight plan: IFR ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 38; injuries: none; airline transport; airplane ratings: multi-engine land, single-engine land; instrument ratings: airplane; medical: class 1; last flight review September 30, 2003; seat: left; flight hours: 7,700 total, 1,140 in this make and model, 5,700 as pilot in command - Co-pilot; age 30; injuries: none; airline transport; airplane ratings: single-engine land, multi-engine land; instrument ratings: airplane; medical: class 1, valid medical--w/ waivers/lim; last flight review September 13, 2003; seat: right; flight hours: 4,660 total, 1,135 in this make and model, 2,340 as pilot in command ## Weather - Conditions: Visual (VMC), Day - Wind: 60° at 5 knots - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 75 °F, dew point 19 °F - Altimeter: 30.18 inHg - Observed at: DEN, 270 nm away 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.