# NTSB DEN06IA034: Boeing B777-200B, N798UA, Denver, CO, January 19, 2006 - Type: NTSB incident investigation - Classification: Incident · No injuries · Incident investigation · Final report - Date: January 19, 2006, 11:15 local (18:15 UTC) - Place: Denver, CO - Coordinates: 39.858333, -104.666664 - Nearby events: https://openairdocs.org/map.md?lat=39.8583&lon=-104.6667&mi=10 - Phase of flight: [Standing](https://openairdocs.org/ntsb-phases/150) (OpenAirDocs' grouping) - Highest injury: No injuries - Injuries: 184 uninjured - Status: Completed, report May 30, 2006 - Report: Approved by Office Director - Parties: FAA Flight Standards District Office - NTSB case key (mKey): 63159 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=DEN06IA034 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/63159/pdf - Page: https://openairdocs.org/ntsb/DEN06IA034 ## Probable cause the truck driver's failure to maintain clearance from the airplane and the boom operator's failure to adequately clear the boom from the airplane. Contributing to the accident was the low visibility due to snow and mist. ## Analysis The airplane was parked at the remote deicing pad and type 4 deicing fluid was being applied to the right rear quadrant and the right wing of the airplane using a deicing truck with a boom. The truck's boom was raised at the time. The driver maneuvered the vehicle too close to the right wing trailing edge at the aileron resulting in the mid-section of the boom coming in contact with the wing. The boom operator cleared the wing for movement when she was not actually clear. The airplane and truck sustained minor damage. An operational inspection of the truck revealed no anomalies. The routine aviation weather report reported visibility, 1/2 statute miles, light snow, and mist. ## Factual narrative On January 19, 2006, approximately 1115 mountain standard time, a Boeing B777-200B, N798UA, owned and operated by United Airlines, sustained minor damage when it was struck by a de-icing truck at deicing pad 3W, Denver International Airport (DEN), Denver, Colorado. Instrument meteorological conditions prevailed at the time of the incident. The scheduled domestic passenger flight was being operated under the provisions of Title 14 CFR Part 121 on an instrument flight rules flight plan. The captain, first officer, 9 cabin crew and 173 passengers were uninjured. The flight had departed the gate at 1030 and was en route to Chicago, Illinois. According to the Pilot/Operator Aircraft Incident Report Form 6120.1/2, the airplane was parked at the remote deicing pad 3W. Type 4 deicing fluid was being applied to the right rear quadrant and the right wing of the airplane using a deicing truck with boom. The deicing truck was moving in the area of the right wing trailing edge, forward toward the wingtip. The truck's boom was raised at the time. The driver maneuvered the vehicle too close to the right wing trailing edge at the aileron resulting in the mid-section of the boom coming in contact with the wing. The right aileron was crushed forward, wrinkled and torn. The airplane returned to the gate where passengers were deplaned uneventfully. The boom on the de-icing truck sustained scratched paint and a small crease in the sheet metal covering. An operational inspection of the truck revealed no anomalies. According to the written statements from the boom operator and deicing truck driver, the boom operator cleared the wing for movement when she was not actually clear. The United Airlines incident report stated that due to falling snow, visibility was poor. The closest official weather observation station was DEN which was located 2 nautical miles east of the occurrence site. The elevation of the weather observation station was 5,431 feet mean sea level. The routine aviation weather report (METAR) for DEN, issued at 1117, reported, wind, 100 degrees at 6 knots; visibility, 1/2 statute miles..., light snow, mist; sky condition, few 700 feet above ground level (agl), overcast, 1,800 feet agl; temperature minus 2 degrees Celsius (C); dewpoint, minus 03 degrees C; altimeter 29.86 inches; remarks, surface visibility 3/4. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - On ground/water collision with object, standing - engine(s) operating - object - vehicle - clearance - not maintained, driver of vehicle (cause) - clearance - not verified, ground personnel (cause) - weather condition - snow (contributing factor) - weather condition - other (contributing factor) ## Aircraft - Registration: [N798UA](https://openairdocs.org/aircraft/N798UA), registered now, S/N 26928, built 1998 (OpenAirDocs) - Reported make and model: Boeing B777-200B - Registry model: [Boeing 777-222](https://openairdocs.org/model/boeing-777-222) (registry code 1385219) (OpenAirDocs) - Registry engine: [Pratt & Whitney PW4000 series](https://openairdocs.org/engine/pratt-whitney-pw4000-series) (registry code 52119, turbo-fan) (OpenAirDocs) - Category: Airplane - Serial number: 26928 - Airframe hours: 34337 - Engines: Pratt & Whitney 4090 90000 lbs thrust turbo fan - Damage: Minor damage - Flight: Part 121 - Registered owner: United Airlines - Airworthiness certificate: Standard, Normal - Last inspection: Continuous airworthiness, January 1, 2006, 146 hours before - Departed: DEN, Denver, CO - Destination: ORD, Chicago, IL - Flight plan: IFR - Airport: DEN, Denver Intl ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 57; injuries: none; flight engineer, airline transport, commercial; airplane ratings: single-engine land, multi-engine land; instrument ratings: airplane; medical: class 1, without waivers/limitations; last flight review May 1, 2005; seat: left; flight hours: 25,000 total, 2,500 in this make and model, 1 in the last 24 hours - Co-pilot; age 45; injuries: none; airline transport, commercial; airplane ratings: single-engine land, multi-engine land; instrument ratings: airplane; medical: class 1, without waivers/limitations; last flight review August 1, 2005; seat: right; flight hours: 14,000 total, 2,000 in this make and model, 190 in the last 90 days, 1 in the last 24 hours ## Weather - Conditions: Instrument (IMC), Day - Wind: 100° at 6 knots - Visibility: 0.75 statute miles - Lowest ceiling: 1,800 ft overcast - Temperature: 28 °F, dew point 27 °F - Altimeter: 29.86 inHg - Observed at: DEN, 2 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). - [Incident 20060119001329I](https://openairdocs.org/incident/20060119001329I), Jan 19, 2006: Boeing 777222, Denver, CO, Minor damage. (-23) Aircraft was being de iced. The de ice truck working the right rear area of the aircraft struck the right wing aileron. The de ice truck was making a… From the NTSB's public API. Aircraft are matched to registry aircraft by N-number and event date; 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.