ANC11LA039 · Cessna 170A
Cessna 170A · Accident: loss of control on ground during landing
From Warren "Bud" Woods Palmer Municipal Airport (PAAQ) to Wasilla Airport (IYS)
Event
- NTSB case
- ANC11LA039
- 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
Cessna 170A
- Aircraft type
- Cessna 170
- 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
- N1742D
- Operator
- Bradley R Subers · private individual
- Onboard fatalities
- Unknown
- Route
- From Warren "Bud" Woods Palmer Municipal Airport (PAAQ), Palmer, AKTo Wasilla Airport (IYS), Wasilla, AK
- Aircraft age
- Not recorded
- 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
- Personnel issues › Task performance
Approximate · Coordinates from the NTSB case API, which marks them as estimated or does not say; no uncertainty radius is established.
NTSB narrative
The pilot said that, when the tailwheel-equipped airplane touched down during a three-point landing, it immediately veered sharply to the left and exited the runway. She was unable to regain control before the airplane collided with a ditch.
The airplane had recently been purchased, and the pilot did not have any flight time in the make and model prior to the purchase. The airplane had been modified with larger/taller main landing gears, larger diameter tires, and a tailwheel assembly from another model of airplane. The pilot said that when the previous owner demonstrated the airplane, he used heavy braking and excessive thrust to get the tailwheel to straighten out. He told her he always did wheel landings as opposed to three-point full stall landings.
A postaccident examination of the airplane revealed that the rotational plane of the tailwheel was not horizontal/parallel to the ground. There was a pronounced negative camber (aft downward tilt), which caused the tailwheel to rotate forward when weight was applied. The tailwheel spring had been extended aft from its normal position, which added additional negative camber. An engineer from the Federal Aviation Administration aircraft certification office said adjustments to the tailwheel should have been made to make the tailwheel's plane of rotation horizontal.
An examination of the airplane's airframe logbook revealed that the airplane's landing gear had been modified under a supplemental type certificate and multiple field approvals. The airplane had been inspected for maintenance conformity, but not engineering.
Due to the multiple landing gear modifications, it is likely that the airplane's landing characteristics were degraded, requiring greater pilot vigilance and skill, particularly during landing.
Probable cause
The pilot's loss of directional control during landing, which resulted in a runway excursion. Contributing to the accident were the effects of multiple modifications to the main and tailwheel landing gear through the supplemental type certificate and FAA field approval process, which adversely changed their geometry, and resulted in degraded controllability during landing.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record ANC11LA039
- Event ID
- 20110528X22348
- Case number
- ANC11LA039
- 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: local date, investigation status, coordinates. Values present in the bulk record are kept.
- The date is the local date; the NTSB stores the UTC date 2011-05-28.
- API snapshot SHA-256: 8362a3fe046aa01efaaff990f51a89ff5468801547ea0614878330014b96e0b6; retrieved 2026-09-15T16:13:18.978Z.