# NTSB CHI97LA242: Boeing B75N1, N75939, Lone Rock, WI, July 30, 1997 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: July 30, 1997, 16:00 local (21:00 UTC) - Place: Lone Rock, WI - Coordinates: 43.180381, -90.200576 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=43.1804&lon=-90.2006&mi=10 - Phase of flight: [Landing](https://openairdocs.org/ntsb-phases/550) (OpenAirDocs' grouping) - Highest injury: No injuries - Injuries: 1 uninjured - Status: Completed, report January 7, 1998 - Report: Approved by Office Director - NTSB case key (mKey): 10658 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CHI97LA242 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/10658/pdf - Page: https://openairdocs.org/ntsb/CHI97LA242 ## Probable cause a locked right brake which resulted in the pilot's inability to maintain direction control of the airplane during the landing roll. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Loss of control - on ground/water, landing - roll - directional control - not possible, pilot in command (cause) - landing gear,normal brake system - locked (cause) - On ground/water encounter with terrain/water, landing - roll ## Analysis The pilot reported the airplane veered 'uncontrollably' to the right during the landing roll. The left wing contacted the ground and the airplane continued the turn until coming to rest on its nose 180 degrees opposite the direction of landing. Post accident inspection of the airplane revealed the crankcase breather tube was routed down the right main landing gear strut allowing oil residue to contaminate the brake system. ## Factual narrative On July 30, 1997, at 1600 central daylight time (cdt), a Boeing B75N1, N75939, operated by a commercial pilot collided with the terrain following a loss of control while landing at the Tri- County Regional Airport, Lone Rock, Wisconsin. The airplane was substantially damaged. The pilot was not injured. Visual meteorological conditions prevailed and it is unknown if a flight plan was filed. The airplane departed from Norman, Oklahoma, at 0630 cdt. The pilot reported that during the landing roll the airplane veered "uncontrollably" to the right. During the turn the left wing contacted the ground. The airplane continued the turn until it came to rest on its nose, 180 degrees opposite the landing direction. Post accident inspection of the airplane by a Federal Aviation Administration Airworthiness Inspector revealed the crankcase breather tube was routed down the right main landing gear strut thus allowing oil residue to contaminate the right brake. ## Aircraft - Registration: [N75939](https://openairdocs.org/aircraft/N75939), registered now, S/N 75-1266 (OpenAirDocs) - Reported make and model: Boeing B75N1 - Registry model: [Boeing B75N1](https://openairdocs.org/model/boeing-b75n1) (registry code 1380144) (OpenAirDocs) - Registry engine: [Pratt & Whitney R-985 series](https://openairdocs.org/engine/pratt-whitney-r-985-series) (registry code 52008, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 75-1266 - Engines: P&W 985-AN1 450 horsepower reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Registered owner: Robert G. Ragozzino - Airworthiness certificate: Special, Experimental (Special) - Departed: OUN, NORMAN, OK - Destination: LNR - Flight plan: Unknown - Airport: LNR, Tri-County, runway 27, 4,020 × 75 ft, asphalt ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 38; commercial; airplane ratings: single-engine land, multi-engine land; instrument ratings: airplane; medical: class 3, unknown; seat: rear; flight hours: 6,900 total, 500 in this make and model, 6,800 as pilot in command, 50 in the last 90 days, 30 in the last 30 days, 6 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 110° at 5 knots - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 81 °F, dew point 55 °F - Altimeter: 30.00 inHg - Observed at: LNR ## FAA reports on this event (1) The FAA's own accident and incident reports, matched to the aircraft by N-number and date (OpenAirDocs). - [Accident 19970730020879A](https://openairdocs.org/incident/19970730020879A), Jul 30, 1997: Boeing B75N1, Lone Rock, WI, Substantial damage. Aircraft right brake locked causing aircraft to ground loop and damage lower left wing pane. (-23) (hayes brakes) r.h. brake lining was contaminated with oil.… ## Other investigations on N75939 (1) 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. - [NTSB FTW80DRG07](https://openairdocs.org/ntsb/FTW80DRG07), Nov 1, 1979: Boeing B75N1 (N75939), Crystal City, TX, substantial damage 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.