# NTSB NYC06IA044: Boeing 717-200, N924ME, Boston, MA, December 21, 2005 - Type: NTSB incident investigation - Classification: Incident · No injuries · Incident investigation · Final report - Date: December 20, 2005, 19:41 local (Dec 21, 2005, 00:41 UTC) - Place: Boston, MA - Coordinates: 42.364166, -71.004997 - Nearby events: https://openairdocs.org/map.md?lat=42.3642&lon=-71.0050&mi=10 - Phase of flight: [Initial climb](https://openairdocs.org/ntsb-phases/350) (OpenAirDocs' grouping) - Highest injury: No injuries - Injuries: 91 uninjured - Status: Completed, report January 31, 2008 - Report: Approved by Office Director - Parties: FAA/FSDO - NTSB case key (mKey): 62968 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=NYC06IA044 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/62968/pdf - Page: https://openairdocs.org/ntsb/NYC06IA044 ## Probable cause Water dilution of the grease, which resulted in the failure of the number 4 wheel bearing. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Airframe/component/system failure/malfunction, takeoff - initial climb - landing gear,wheel - failure - fluid,water - contamination,water (cause) - lubricant,grease - deteriorated ## Analysis During takeoff, air traffic controllers observed sparks coming from the rear of the Boeing 717-200, and shortly thereafter, the pilot reported a problem with the right main landing gear and gear door, with the landing gear in the retracted position. The airplane circled for about an hour and a half to burn fuel, and the captain subsequently performed an uneventful landing. Examination of the airplane revealed that the number 4 wheel bearing failed, and the wheel race welded to the axle. As the wheel continued to rotate, the remaining races and bearings fragmented and separated from the wheel. Examination of the remaining three wheel hubs revealed the presence of water. A similar incident occurred approximately 10 months prior involving another Boeing 717-200; however, due to the catastrophic damage to the tire and bearings, it could not be determined whether or not water was present. As a result of the second incident, the manufacturer incorporated a hubcap gasket to prevent moisture from becoming trapped in the wheels. ## Factual narrative On December 20, 2005, at 1941 eastern standard time, a Boeing 717-200, N924ME, operated by Midwest Airlines Inc., as flight 210, incurred minor damage during a takeoff from General Edward Lawrence Logan International Airport (BOS), Boston, Massachusetts. The airplane returned to the airport, and landed without incident at 2153. There were no injuries to the 2 certificated airline transport pilots, 2 flight attendants, and 87 passengers. Night visual meteorological conditions prevailed for the flight that was destined for General Mitchell International Airport (MKE), Milwaukee, Wisconsin. An instrument flight rules flight plan was filed for the scheduled domestic flight conducted under 14 CFR Part 121. During the takeoff from runway 22R, air traffic controllers observed sparks coming from the rear of the airplane, and shortly thereafter, the pilot reported a problem with the right main landing gear and gear door, with the landing gear in the retracted position. The airplane circled for about an hour and a half to burn fuel, and the captain subsequently performed an uneventful landing on runway 33L. The airplane was then towed to the gate, and the passengers deplaned normally. Examination of the airplane by a Federal Aviation Administration (FAA) inspector revealed that the number 4 wheel bearing failed, and the wheel race was welded to the axle. The remaining races and bearings were fragmented and separated from the wheel. The remaining three wheels were examined, and approximately 1/2 to 1 cup of water was observed inside the number 1 wheel hubcap. Additionally, the grease inside the hubcap appeared "heavily diluted." The number 2 and number 3 wheel hubcaps also contained "slight traces" of water. At the time of the incident, the airplane had accrued approximately 233 cycles and 425 hours since delivery from Boeing. According to the operator, the wheel and tire had not been removed since delivery. A similar incident occurred on February 22, 2004, involving another B-717-200, N919ME; however, due to the catastrophic damage to the tire and bearings, it could not be determined whether or not water was present. As a result of the incident involving N924ME, Boeing surveyed a majority of the B-717 operators for water in the wheels. The operators that responded reported finding no fluid of any type; however, as a precautionary measure, Boeing incorporated a hubcap gasket to prevent moisture from becoming trapped in the wheels. ## Aircraft - Registration: N924ME (not matched to a registry record) - Reported make and model: Boeing 717-200 - Category: Airplane - Serial number: 55190 - Airframe hours: 355 - Engines: Rolls-Royce BR700-715A1 17700 lbs thrust turbo fan - Damage: Minor damage - Flight: Part 121 - Operator: Midwest Airlines Inc. - Registered owner: US Bank NA Trustee - Airworthiness certificate: Standard, Transport - Last inspection: Continuous airworthiness, December 1, 2005, 355 hours before - Departed: BOS, Boston, MA - Destination: MKE, MILWAUKEE, WI - Flight plan: IFR - Airport: BOS, Logan International Airport, runway 27, 7,000 × 150 ft, asphalt ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 48; injuries: none; airline transport; airplane ratings: multi-engine land; instrument ratings: airplane; medical: class 1, with waivers/limitations; last flight review October 1, 2005; seat: left - Co-pilot; age 39; injuries: none; airline transport; airplane ratings: multi-engine land; instrument ratings: airplane; medical: class 2, without waivers/limitations; last flight review June 1, 2005; seat: rear ## Weather - Conditions: Visual (VMC), Night - Wind: 270° at 14 knots, gusting 21 - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 28 °F, dew point 12 °F - Altimeter: 29.95 inHg - Observed at: BOS ## 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 20051220029759I](https://openairdocs.org/incident/20051220029759I), Dec 20, 2005: Boeing 717200, Boston, MA. (-23) Midwest airlines, flight 210, aircraft N924ME, Boeing B-717-200, departed Boston, MA at 1941 EST, 12/20/05 runway 22R. Boston ATC observed sparks coming… 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.