National Transportation Safety Board Aviation Accident Final Report Location: MISSOULA, MT Accident Number: Date & Time: 09/22/2000, 0220 MDT Registration: N99TH Aircraft: Beech B99 Aircraft Damage: Substantial Defining Event: Injuries: 2 None Flight Conducted Under: Part 135: Air Taxi & Commuter - Non-scheduled Analysis The airplane touched down on the centerline of runway 29. When the pilot applied brakes 'the right brake locked up' and the airplane immediately veered to the right. The pilot applied left brake, left rudder and reversed the left propeller, however, the airplane continued to the right. The airplane collided with a taxiway light and runway marker before departing the right side of the runway. The airplane sustained substantial damage to the fuselage. Post-accident photographs of the airplane revealed ice and snow deposits on the cargo pod, right lower engine nacelle, main landing gear strut and right dual brake assembly. The landing runway in Missoula was dry, however, the departure runway at Billings was contaminated with snow and slush. Post-accident inspection of the airplane, by inspectors from the FAA Helena, Montana, Flight Standards District Office, revealed no evidence of system mechanical malfunction that would result in a brake failure. Probable Cause and Findings The National Transportation Safety Board determines the probable cause(s) of this accident to be: A loss of directional control due to a brake locked as a result of snow and ice contamination. Page 1 of 5
Findings Occurrence #1: LOSS OF CONTROL - ON GROUND/WATER Phase of Operation: LANDING Findings 1. (C) LANDING GEAR,NORMAL BRAKE SYSTEM - CONTAMINATION 2. (C) LANDING GEAR,NORMAL BRAKE SYSTEM - LOCKED 3. (C) DIRECTIONAL CONTROL - NOT POSSIBLE - PILOT IN COMMAND ---------- Occurrence #2: ON GROUND/WATER COLLISION WITH OBJECT Phase of Operation: LANDING - ROLL Page 2 of 5
Factual Information On September 22, 2000, about 0220 mountain daylight time (MDT), a Beech B99, N99TH, sustained substantial damage during landing on runway 29, at Missoula International Airport, Missoula, Montana. The airplane was operated by Alpine Air of Provo, Utah, as a domestic cargo flight under the provisions of Title 14, Part CFR 135, when the accident occurred. The commercial pilot, and the airline employee passenger were not injured. Visual meteorological conditions prevailed and an instrument flight plan was filed. The flight originated at Billings, Montana, about 0100 MDT. In a written statement, the pilot reported that the airplane touched down on the centerline of runway 29. He stated that when he applied wheel brakes, "the right brake locked up" and the airplane immediately veered to the right. The pilot applied left brake, left rudder and reversed the left propeller, however, the airplane continued to the right. The airplane collided with a taxiway light and runway marker before departing the right side of the runway. The airplane sustained substantial damage to the fuselage. A skid mark that coincides with the airplanes right main landing gear was noted on the landing runway. The skid mark originated near the runway centerline and continues to the point where the airplane left the runway. Post-accident photographs of the airplane, taken on the night of the accident, revealed ice and snow deposits on the cargo pod, right lower engine nacelle, main landing gear strut and right dual brake assembly. The landing runway in Missoula was dry, however, the departure airport at Billings was contaminated with approximately 6 inches of snow and slush. On September 22, FAA personnel from the Helena, Montana, Flight Standards District Office, inspected the airplane and reported that there was no evidence of system mechanical malfunction that would have resulted in a brake failure (Report attached). Pilot Information Certificate: Airline Transport; Commercial Age: 28, Male Airplane Rating(s): Multi-engine Land; Single-engine Land Seat Occupied: Other Aircraft Rating(s): None Restraint Used: Seatbelt, Shoulder harness Instrument Rating(s): Airplane Second Pilot Present: No Instructor Rating(s): Airplane Single-engine Toxicology Performed: No Medical Certification: Occupational Pilot: Flight Time: Class 1 Valid Medical--w/ waivers/lim. Left Last Medical Exam: 05/08/2000 Last Flight Review or Equivalent: 4696 hours (Total, all aircraft), 1629 hours (Total, this make and model), 4507 hours (Pilot In Command, all aircraft), 327 hours (Last 90 days, all aircraft), 116 hours (Last 30 days, all aircraft), 3 hours (Last 24 hours, all aircraft) Page 3 of 5
Aircraft and Owner/Operator Information Aircraft Manufacturer: Beech Registration: N99TH Model/Series: B99 B99 Aircraft Category: Airplane Year of Manufacture: Amateur Built: No Airworthiness Certificate: Normal Serial Number: U-155 Landing Gear Type: Retractable - Tricycle Seats: 2 Date/Type of Last Inspection: 09/19/2000, AAIP Certified Max Gross Wt.: 10900 lbs Time Since Last Inspection: 136 Hours Engines: 2 Turbo Prop Airframe Total Time: 36485 Hours Engine Manufacturer: P&W ELT: Installed, not activated Engine Model/Series: PT6A-28 Registered Owner: CLB LEASING Rated Power: 680 hp Operator: ALPINE AIR Air Carrier Operating Certificate: Air Cargo Operator Does Business As: Operator Designator Code: TIMA Meteorological Information and Flight Plan Conditions at Accident Site: Visual Conditions Condition of Light: Night/Dark Observation Facility, Elevation: MSO, 3205 ft msl Observation Time: 0156 MDT Distance from Accident Site: 0 Nautical Miles Direction from Accident Site: 0 Lowest Cloud Condition: Unknown / 0 ft agl Temperature/Dew Point: 3 C / -7 C Lowest Ceiling: Broken / 8500 ft agl Visibility 10 Miles Wind Speed/Gusts, Direction: 11 knots, 90 Visibility (RVR): 0 ft Altimeter Setting: 30 inches Hg Visibility (RVV): 0 Miles Precipitation and Obscuration: Departure Point: BILLINGS, MT (BIL) Type of Flight Plan Filed: IFR Destination: (MSO) Type of Clearance: IFR Departure Time: 0100 MDT Type of Airspace: Class D Airport Information Airport: MISSOULA INTERNATIONAL AI (MSO) Runway Surface Type: Asphalt Airport Elevation: 3205 ft Runway Surface Condition: Dry Runway Used: 29 IFR Approach: Runway Length/Width: 9501 ft / 150 ft VFR Approach/Landing: Full Stop; Straight-in Page 4 of 5
Wreckage and Impact Information Crew Injuries: 2 None Aircraft Damage: Substantial Passenger Injuries: N/A Aircraft Fire: None Ground Injuries: N/A Aircraft Explosion: None Total Injuries: 2 None Latitude, Longitude: Administrative Information Investigator In Charge (IIC): DENNIS J HOGENSON Adopted Date: 03/26/2003 Additional Participating Persons: Publish Date: Investigation Docket: BOB C SPEICHER; HELENA, MT NTSB accident and incident dockets serve as permanent archival information for the NTSB s investigations. Dockets released prior to June 1, 2009 are publicly available from the NTSB s Record Management Division at pubinq@ntsb.gov, or at 800-877-6799. Dockets released after this date are available at http://dms.ntsb.gov/pubdms/. The National Transportation Safety Board (NTSB), established in 1967, is an independent federal agency mandated by Congress through the Independent Safety Board Act of 1974 to investigate transportation accidents, determine the probable causes of the accidents, issue safety recommendations, study transportation safety issues, and evaluate the safety effectiveness of government agencies involved in transportation. The NTSB makes public its actions and decisions through accident reports, safety studies, special investigation reports, safety recommendations, and statistical reviews. The Independent Safety Board Act, as codified at 49 U.S.C. Section 1154(b), precludes the admission into evidence or use of any part of an NTSB report related to an incident or accident in a civil action for damages resulting from a matter mentioned in the report. Page 5 of 5