- Date
- October 8, 2004, 18:00 local (23:00 UTC)
- Place
- Augusta, KS
- Injuries
- 1 uninjured
- Damage
- Substantial damage
- Phase of flight
- Landing
- Aircraft
- N701TDSinclair Zenith 701
- Weather
- Visual (VMC) · Day
- Status
- Completed · report December 28, 2004
- Report
- Approved by Office Director
- Parties
- Federal Aviation Administration
- FAA report
- 20041008026799A
- Case key
- 60390
From the NTSB’s public API. By law, NTSB reports can’t be used as evidence in lawsuits over the accident.
On this page
Probable cause
The manufacturer's inadequate design/production of the landing gear axle leading to its separation and the airplanes subsequent nose over during the landing roll.. A factor was the axle's separation from its spring.
Sequence of events
NTSB’s coding before 2008: each occurrence and phase of flight, and the causes and factors under it. The codes are defined in NTSB’s coding manual.
Analysis
The experimental amateur-built tailwheel airplane sustained substantial damage when the airplane nosed over during a landing. The pilot's accident report stated, "On touch down at private strip, landing slightly heavy but nothing excessive. Left main wheel contacted a slight depression and the axle separated. Left gear mainspring dug in causing plane to nose over [and] rotate to the left. Left over momentum caused the right wing to then strike the runway. After stopping, the tail then dropped back onto the ground." The pilot's safety recommendation stated that the "accident would not have happened if the axle assembly have been designed with adequate structure ... ." The axle manufacturer stated that ownership changed in November of 2000. The earlier company produced the WHLA7 Flange Mount Axles shipped with the accident airplane's kit. The current company designed the same model axle to have a "reinforcing ring welded to the base at the axle flange interface and the larger diameter hole in the flange base that accepts the axle stub." The manufacturer issued a Service Bulletin SRV101804 that showed the new design and an exchange program. That service bulletin is available through their website, www.matcomfg.com, on its technical support page.
Factual narrative
On October 8, 2004, about 1800 central daylight time, an experimental amateur-built tailwheel Sinclair Zenith CH 701 airplane, N701TD, sustained substantial damage when the airplane nosed over during a landing at a private airstrip near Augusta, Kansas. The personal flight was operating under 14 CFR Part 91. Visual meteorological conditions prevailed at the time of the accident. No flight plan was on file. The pilot reported no injuries. The flight originated from a private airstrip near Augusta, Kansas, at 1750.
The pilot's accident report stated:
On touch down at private strip, landing slightly heavy but nothing
excessive. Left main wheel contacted a slight depression and the axle
separated. Left gear mainspring dug in causing plane to nose over
[and] rotate to the left. Left over momentum caused the right wing
to then strike the runway. After stopping, the tail then dropped back
onto the ground.
The pilot stated that there was 68.5 hours of total time on the axle assembly and his safety recommendation stated that the "accident would not have happened if the axle assembly have been designed with adequate structure ... ."
Matco Mfg, the axle manufacturer, was contacted. The manufacturer stated that ownership changed in November of 2000. The earlier company produced the WHLA7 Flange Mount Axles shipped with the accident airplane's kit. The current company designed the same model axle to have a "reinforcing ring welded to the base at the axle flange interface and the larger diameter hole in the flange base that accepts the axle stub." The manufacturer issued a Service Bulletin SRV101804 that showed the new design and an exchange program. That service bulletin is available through their website, www.matcomfg.com, on its technical support page and is appended to the docket material associated with this case.
Aircraft
- Registration
- N701TD
- Reported as
- Sinclair Zenith 701
- Category
- Airplane, amateur-built
- Serial number
- 7-3993
- Engine
- Rotax 912 UL, 80 horsepower, reciprocating
- Damage
- Substantial damage
- Flight
- Personal · Part 91
- Registered owner
- Michael A. Sinclair
- Airworthiness certificate
- Special, Experimental (Special)
- Departed
- PVT · Augusta, KS
- Destination
- PVT · Augusta, KS
- Airport
- PVT, runway 36, 700 × 70 ft, grass/turf
Matched to the registry by N-number and the event date; the registry’s history has gaps, so older matches can be wrong. Compare the reported make and model.
Flight crew
As NTSB recorded them. NTSB leaves out names.
- Role
- Pilot
- Age
- 55
- Injuries
- None
- Certificate
- Private
- Airplane ratings
- Single-engine land
- Medical
- Class 3, Valid Medical--w/ waivers/lim
- Last flight review
- October 20, 2003
- Seat
- Left
- Flight hours
- 148 total · 67 in this make and model · 148 as pilot in command
Weather
- Conditions
- Visual (VMC) · Day
- Wind
- 10° at 7 knots
- Visibility
- 10 statute miles
- Lowest ceiling
- None
- Temperature
- 81 °F, dew point 54 °F
- Altimeter
- 30.04 inHg
- Observed at
- AAO, 15 nm away
FAA reports on this event · 1
The FAA’s own accident and incident reports, matched to the aircraft by N-number and date.