Maule M 7-235C accident near Klamath Falls, Oregon, August 24, 2017
On August 24, 2017 at about 4:40 pm local time, a 2001 Maule M 7-235C, registered N6447M, was substantially damaged in an accident during landing (landing roll) near Klamath Falls, Oregon (Crater Lake-Klamath Rgnl airport). It was a personal flight under general aviation rules (Part 91). No one was hurt; 1 person was on board or involved. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
The pilot's failure to follow the pre-takeoff checklist and the failure of the left main landing gear brake due to a damaged brake master cylinder piston rod, which resulted in a stuck left brake and subsequent loss of control during the landing roll.
Source: NTSB aviation accident database, copy made November 2, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- August 24, 2017 · about 4:40 pm local time · cases in 2017
- Place
- Klamath Falls, Oregon · Crater Lake-Klamath Rgnl · cases near this airport · map
- Type
- Accident
- Injuries
- No one was hurt; 1 person was on board or involved.
- Weather
- visual conditions (good weather)
- Aircraft
- Maule M 7-235C 235C, built 2001 · all M 7-235Cs on the register
- Registration
- N6447M · registry record · serial 25072C
- Damage
- Substantial damage
- Flight
- Personal flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
The commercial pilot reported that he did not note any drag or restrictions from the wheel brakes during taxi or takeoff. When the airplane touched down at the destination airport, it immediately began to veer left. The pilot was unable to overcome the uncommanded movement despite his application of right rudder and right brake, and the airplane nosed over and came to rest inverted. The pilot reported that as he was preparing the airplane for the flight, he removed the chocks and the airplane started to roll backwards. He assumed that his son had released the parking brake and replaced the downhill chocks the night before the accident when he finished washing the airplane. The pilot completed the preflight but did not follow the checklist to confirm that the parking brake was disengaged before departing on the flight. Postaccident, the brake knob was found in the ON (engaged) position. However, the pilot reported the absence of any drag during ground operations indicating that the parking brake may not have been engaged before taking off, which can occur if the toe brakes are not fully extended when the parking brake is set. Postaccident testing revealed that the left brake became stuck multiple times due to the interference of circumferential gouges and ridges on the left brake master cylinder piston rod and bushing, which likely resulted from normal operation of the parking brake. Because the parking brake knob was in the ON position during the flight, the left brake could have been set by depressing the toe brake. The rod damage would have then prevented the free travel required for the piston to release brake pressure and disengage the left brake, thereby causing the airplane to veer left after touching down. Although a visual inspection of the rod could have detected the wear, review of the maintenance logs since 2010 showed that the master cylinder had not been disassembled and inspected, nor was it required to be.
The complete narrative as the NTSB published it. The NTSB's docket holds the report as a PDF and any photographs, statements and other documents from the investigation.
The factual record from the NTSB's investigation tables, in plain English
What happened, in order
- Sys/Comp malf/fail (non-power) during landing (landing roll)
- Loss of control on ground during landing (landing roll) defining event
- Nose over/nose down during landing (landing roll)
- Collision with terrain or object (not controlled flight into terrain) during landing (landing roll)
The NTSB's findings
- cause Personnel issues › Task performance › Use of equip/info › Use of checklist › Pilot
- cause Personnel issues › Action/decision › Action › Forgotten action/omission › Pilot
- cause Aircraft › Aircraft systems › Landing gear system › Landing gear brakes system › Failure other cases naming the landing gear
Pilot
- Certificate: commercial pilot
- Ratings: multi-engine land; single-engine land; instrument: airplane; rotorcraft: glider
- Flight time: 7,200 hours in all; 140 in this make and model
- Last flight review: July 30, 2016
- Medical certificate: Class 3 (with waivers/limitations)
- Seat: left
- Injury: no injuries
The aircraft
- Airframe total time: 896 hours
- Last inspection: annual inspection, April 6, 2017; 48 hours since
- Maximum gross weight: 2,500 lb
- Seats: 4
- Landing gear: fixed
- Engine: Lycoming IO-540 (piston); 896 hours total
The flight
- Departed from: PRIV Klamath Falls OR at 4:10 pm
- Destination: LMT Klamath Falls OR
- Flight plan: none
- Runway 32, 10,301 ft by 150 ft
Weather at the time
- Light: daylight
- Wind: from 030° at 3 knots
- Sky: clear
- Temperature: 72°F (22°C), dew point 54°F (12°C)
- Altimeter: 30.04 inHg
- Observation at 4:53 pm from LMT
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Flight crew | 1 |
Photographs from the investigation 2 pictures from the NTSB's docket, as the NTSB released them
Photo 1 – Forward Quartering View of Accident Airplane
Photo 2 – Photo of Left Brake Master Cylinder Piston Rod AssemblyThe NTSB's photographs with the NTSB's captions, at screen size. Open a picture to see it full size or to report one that should not be shown.
Documents from the investigation the NTSB's docket: the evidence folder behind the report
7 documents, released by the NTSB on August 10, 2018. View them here, or download them; the NTSB redacts some personal details before release, and this site shows the NTSB's own titles rather than its file names.
| # | Document | What it is | |
|---|---|---|---|
| 1 | Pilot/operator Aircraft Accident Report, NTSB Form 6120.1 | PDF, 9 pages | View Download |
| 2 | Weather Reports and Records | PDF, 2 pages | View Download |
| 3 | Record of Conversations | PDF, 7 pages | View Download |
| 4 | FAA Inspector's Statement | PDF, 5 pages | View Download |
| 5 | NTSB Brake Examination Report | PDF, 4 pages | View Download |
| 6 | Release of Aircraft Wreckage, NTSB Form 6120.15 | PDF, 1 page | View Download |
| 7 | Accident Photographs | PDF, 2 pages · our copy | View Download |
The same docket at the NTSB · documents without a copy here are fetched from the NTSB when you open them.
Connections how this case links to the rest of the register
- N6447M on the register today · the tail number may have moved to another aircraft since
- Maule M-7 275 registered today · the model family and its accident history
- Maule 1,345 aircraft on the register
- Engine: Lycoming IO-540 4,223 aircraft carry this series today · as the NTSB recorded it
- Crater Lake/Klamath Regional · nearest airport
- Accidents and incidents in Oregon 1,864 since 1982 · 279 in the last ten years
- Oregon 7,011 aircraft registered
The whole map of how records connect · these connections as data: /graph/accident/WPR17LA192.json.
The bigger picture in Aviation Analytics: accidents over time since 1982, by model, by phase of flight and conditions, by place and on the map.
Everything on this page comes from the NTSB's public records. The narrative, probable cause and findings are the NTSB's own words; the coded tables behind the report are written out in plain English, with pilots' ages, home towns and medical details left out. The documents and photographs are the NTSB's docket, shown as the NTSB released them. This site's own text does not name anyone involved, its policy at this time. A preliminary report can change; the final report usually follows one to two years later, and the page is refreshed when it does.