Ravalli Co. Airport
Aircraft Accident/Incident Report

Hamilton, Montana 59840
Thursday, July 2, 1998 11:49 MDT

NTSB Narrative Summary Released at Completion of Accident

The pilot reported that, after a normal approach and touchdown, he applied the brakes and thrust reversers. He stated that as the aircraft slowed to 60 to 70 knots, it veered to the right and exited the side of the runway. The pilot regained directional control after the aircraft exited the runway. Before the aircraft came to a stop, the right wing collided with the VASI lights for the opposite runway. Skid marks leading to the exit point on the runway, indicated that the right-side tire marks displayed heavier braking action than on the left side. Post-accident testing performed on the anti-skid generators revealed that the left-side inboard and outboard generators failed the manufacturer's specifications. The right-side inboard and outboard generators passed all manufacturers specifications. The left-side generators were disassembled. The inspection did not reveal any anomalies. A slight difference in the brush wear between the brush fittings was noted between the two generators. A short circuit between two adjacent collectors was found in the outboard generator rotor fitting. The manufacturer's representative reported that the short circuit was not due to a failure within a cell of the rotor, but was likely due to contamination present between the two collectors.

NTSB Probable Cause Narrative

Partial failure of the anti-skid brake system due to contamination.

Event Information

Type of Event Accident
Event Date 7/2/1998
Event Day of the Week Thursday
Time of Event 1149
Event Time Zone Mountain Daylight Time
Event City HAMILTON
Event State MONTANA
Event Country --
Zipcode of the event site 59840
Event Date Year 1998
Event Date Month 7
MidAir Collision Indicator No
On Ground Collision occurred ? No
Event Location Latitude --
Event Location Longitude --
Event Location Airport RAVALLI CO.
Event Location Nearest Airport ID 6S5
Indicates whether the acc/inc occurred off or on an airport On Airport
Distance from airport in statute miles --
Degrees magnetic from airport --
Airport Elevation 3638
Weather Briefing Completeness Unknown
Investigator's weather source Pilot
Time of the weather observation 0
Direction of event from weather observation facility (degrees) 0
Weather Observation Facility ID
Elevation of weather observation facility 0
Distance of event from weather observation facility (units?) 0
Time Zone of the weather observation
Lighting Conditions Day
Lowest Ceiling Height 0
Lowest Non-Ceiling Height 0
Sky/Lowest/Cloud Conditions Clear
Sky Condition for Lowest Ceiling None
Visibility Runway Visual Range (Feet) 0
Visibility Runway Visual Value (Statute Miles) 0
Visibility (Statute Miles) 50
Air Temperature at event time (in degrees celsius) 18
Dew Point at event time (in degress fahrenheit) --
Wind Direction (degrees magnetic) 0
Variable Wind Indicator Variable
Wind Speed (knots) 8
Wind Velocity Indicator Unknown
Wind Gust Indicator Unknown
Wind Gust (knots) 0
Altimeter Setting at event time (in. Hg) 29
Density Altitude (feet) --
Intensity of Precipitation Unknown
METAR weather report --
Event Highest Injury None
On Ground, Fatal Injuries 0
On Ground, Minor Injuries 0
On Ground, Serious Injuries 0
Injury Total Fatal --
Injury Total Minor --
Injury Total None 9
Injury Total Serious --
Injury Total All --
Investigating Agency NTSB
NTSB Docket Number (internal use) 1587
NTSB Notification Source --
NTSB Notification Date Jul 7 1998 12:00AM
NTSB Notification Time 730
Fiche Number and/or location -used to find docket information IMAGE
Date of most recent change to record Feb 23 2001 1:57PM
User who most recently changed record dbo
Basic weather conditions Visual Meteorological Cond
FAA District Office --

Aircraft Involved

Aircraft #1

Aircraft Registration Number N900CS
NTSB Number SEA98LA118
Missing Aircraft Indicator N
Federal Aviation Reg. Part Part 91: General Aviation
Type of Flight Plan filed IFR
Flight plan Was Activated? --
Damage Substantial
Aircraft Fire None
Aircraft Explosion None
Aircraft Manufacturer's Full Name Dassault
Aircraft Model MYSTERE FALCON 900
Aircraft Series Identifier MYSTERE FA
Aircraft Serial Number 104
Certified Max Gross Weight 46500
Aircraft Category Airplane
Aircraft Registration Class U.S. Registered/U.S. Soil
Aircraft is a homebuilt? No
Flight Crew Seats --
Cabin Crew Seats --
Passenger Seats --
Total number of seats on the aircraft 15
Number of Engines 3
Fixed gear or retractable gear Retractable
Aircraft, Type of Last Inspection Continuous Airworthiness
Date of Last Inspection Mar 7 1998 12:00AM
Airframe hours since last inspection 83
Airframe Hours 3119
ELT Installed Yes
ELT Activated No
ELT Aided Location of Event Site Unknown
ELT Type --
Aircraft Owner Name CHARLES SCHWAB & CO.
Aircraft Owner Street Address 101 MONTGOMERY ST.
Aircraft Owner City SAN FRANCISCO
Aircraft Owner State CA
Aircraft Owner Country
Aircraft Owner Zipcode 94104
Operator is an individual? --
Operator Name TAG AVIATION USA
Operator Same as Owner? No
Operator Is Doing Business As --
Operator Address Same as Owner? No
Operator Street Address SAN FRANCISCO INT'L AIRPORT
Operator City SAN FRANCISCO
Operator State CA
Operator Country
Operator Zip code 94128
Operator Code
Owner has at least one certificate None
Other Operator of large aircraft? No
Certified for Part 133 or 137 Operation Unknown
Operator Certificate Number --
Indicates whether an air carrier operation was scheduled or not --
Indicates Domestic or International Flight --
Operator carrying Pax/Cargo/Mail --
Type of Flying (Per_Bus / Primary) Personal
Second Pilot on Board Yes
Departure Point Same as Event No
Departure Airport Code SFO
Departure City SAN FRANCISCO
Departure State CA
Departure Country
Departure Time 912
Departure Time Zone PDT
Destination Same as Local Flt crash at destination city
Destination Airport Code
Destination City
Destination State
Destination Country
Specific Phase of Flight --
Report sent to ICAO? --
Evacuation occurred --
Date of most recent change to record Feb 23 2001 1:57PM
User who most recently changed record dbo
Since inspection or accident --
Event Location Runway Number and Location 34
Runway Length 4200
Runway Width 75
Sight Seeing flight No
Air Medical Flight No
Medical Flight --