ERA18LA270 · Maule M7 235C
Maule M7 235C · Accident: landing gear collapse
From Floresville, TX to Floresville, TX
Event
- NTSB case
- ERA18LA270
- 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 M7 235C
- Aircraft type
- Maule M7
- 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
- N969AW
- Operator
- Unknown
- Onboard fatalities
- Unknown
- Route
- From Floresville, TXTo Floresville, TX
- Aircraft age
- About 15 years (built 2003)
- 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
- Landing gear collapse
- 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
Approximate · Coordinates as recorded by the NTSB; no uncertainty radius is established.
NTSB narrative
The flight instructor and the private pilot-rated student, who was in the left seat and was also the airplane owner, were practicing approaches. Upon landing, the pilots heard a loud popping noise, and the instructor then initiated a go-around. Subsequently, the pilot felt vibration under the floorboard. The pilots thought that a tire might have blown. The instructor flew the approach and conducted a three-point landing, and just before the airplane came to a stop, the left main landing gear (MLG) collapsed, which resulted in substantial damage to the left wing.
An examination of the left MLG revealed that its inboard attachment bolt and nut were missing. After the accident, the bolt was found along the path of the landing rollout. Examination of the attachment bolt revealed that the bolt threads were undamaged. The attachment nut was not found. The right MLG's inboard attachment bolt and nut were found still attached; however, they were loose, with only two to three threads visible past the nut.
The inboard attachment bolts were upgraded high-strength bolts. The airframe manufacturer had issued a service letter (SL) that stated that, when using the high-strength bolts, the outboard attachment bolts required the same amount of torque as indicated in the airplane maintenance manual but that the inboard attachment bolts required a higher torque amount than the standard bolts. However, a review of the maintenance manual revealed that it did not include the new, higher torque requirements specified in the SL. Therefore, mechanics who only follow the maintenance manual may not be aware that higher torque values are required.
A review of the airplane maintenance records revealed that its last annual inspection was completed about 6 months before the accident. The mechanic who performed the inspection reported that he did not verify the torque on the bolts, that he only used his hands to confirm that they were secure, and that he did not reference the SL during the inspection. It could not be determined whether the mechanic's failure to verify the torque on the bolts or the insufficient torque values in the MM led to the torque on the left inboard MLG attachment bolt being insufficient and the resultant collapse of the left MLG.
Probable cause
The separation of the left inboard main landing gear (MLG) attachment bolt due to insufficient torque, which resulted in the collapse of the left MLG.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record ERA18LA270
- Event ID
- 20181011X61348
- Case number
- ERA18LA270
- 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. 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: 182f38c461dfda0492f2a967ce8d568a183216aa3eab602e3d73e926a2b269c2; retrieved 2026-09-16T08:19:57.112Z.