WPR17LA192 · Maule M 7-235C
Maule M 7-235C · Accident: loss of control on ground during landing
From PRIV · Klamath Falls, OR to Crater Lake-Klamath Regional Airport (LMT)
Event
- NTSB case
- WPR17LA192
- Event typeAccident: someone killed or seriously injured, or the aircraft substantially damaged (NTSB definition). Incident: an occurrence that affected or could have affected safety, short of that. Glossary
- Accident
- InvestigationHow far the investigation had got when the record was published: preliminary, ongoing, final or completed. Unknown where the source does not say. Glossary
- Completed
- API-reported fatalities
- 0 · all aircraft and ground
- Ground fatalities
- Unknown
- OperationWhat kind of flying it was, grouped by the rules it flew under: airline (US Part 121), air taxi and commuter (Part 135), general aviation (Part 91 and similar), military or government. Glossary
- General aviation
- WeatherVisual meteorological conditions (VMC): good enough to fly by looking outside. Instrument conditions (IMC): cloud or low visibility, flying by instruments. Glossary
- Visual Meteorological Cond
Maule M 7-235C
- Aircraft type
- Maule M-7
- Category
- Airplane
- RegistrationThe aircraft's tail number, such as N12345 or G-ABCD. Registrations are reissued, so the same one years apart can be a different aircraft. Glossary
- N6447M
- Operator
- Unknown
- Onboard fatalities
- Unknown
- Route
- From PRIV · Klamath Falls, ORTo Crater Lake-Klamath Regional Airport (LMT), Klamath Falls, OR
- Aircraft age
- About 16 years (built 2001)
- Flight rulesThe regulations the flight operated under: in the US, Part 91 (general aviation), Part 121 (airlines), Part 135 (air taxi and commuter) and others; for flights abroad, the NTSB's coarser commercial or non-commercial code. Glossary
- Part 91: General Aviation
- Phase of flightThe stage of the flight when things started to go wrong: standing, taxi, takeoff, initial climb, en route, maneuvering, approach or landing. Glossary
- Landing · landing roll
- Defining eventThe single coded event the NTSB judges best describes what happened (records from 2008 on). Older records name the first occurrence in the sequence instead. Glossary
- Loss of control on ground
- DamageDestroyed: beyond practical repair. Substantial: damage that affects the structure, performance or handling and normally needs major repair. Minor: less than that. Glossary
- Substantial
Cause areas
- Aircraft › Aircraft systems
- Personnel issues › Action/decision
- Personnel issues › Task performance
Approximate · Coordinates from the NTSB case API, not marked as estimated; no uncertainty radius is established.
NTSB narrative
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.
Probable cause
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.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record WPR17LA192
- Event ID
- 20170824X33853
- Case number
- WPR17LA192
- Dataset
- full-current
- Source SHA-256
- 5cf380f0061817c0331a6b2d8cc7e0ee3a79bea469a1001dc5c10e56f35f5ab3
Source notes (4)
- Unreviewed is an editorial label, not an investigation status. API-sourced is not report-checked or human-reviewed. Explicit event totals are used without summing aircraft injury tables; onboard allocation is withheld. Unknown values remain unknown. The operation category is mapped from the NTSB-reported FAR part and has not been reviewed.
- Filled from the NTSB case API where the bulk record had no value: investigation status, coordinates. Values present in the bulk record are kept.
- The date is the local date, which is the same as the UTC date the NTSB stores.
- API snapshot SHA-256: a58ef09c7403d284fc03adb9c31b24f23544e85847b29575ddc123d2a06e6257; retrieved 2026-09-16T05:45:01.146Z.