Pitts S-1S Special, N93DB: Accident occurred September 25, 2014 at Sedona Airport (KSEZ), Arizona

Additional Participating Entity: 
Federal Aviation Administration / Flight Standards District Office; Scottsdale, Arizona 

Aviation Accident Final Report - National Transportation Safety Board:  https://app.ntsb.gov/pdf

Aviation Accident Data Summary - National Transportation Safety Board:  https://app.ntsb.gov/pdf

Investigation Docket - National Transportation Safety Board:  https://dms.ntsb.gov/pubdms

http://registry.faa.gov/N93DB

Location: Sedona, AZ
Accident Number: WPR14CA390
Date & Time: 09/25/2014, 0830 MST
Registration: N93DB
Aircraft: WILLIAM M OPRENDEK PITTS S1S
Aircraft Damage: Substantial
Defining Event: Sys/Comp malf/fail (non-power)
Injuries: 1 None
Flight Conducted Under:  Part 91: General Aviation - Personal

Analysis

The pilot/builder of the experimental amateur-built, tailwheel-equipped airplane had just completed a flight as part of phase one flight testing. He reported an uneventful approach to landing, with the main landing gear touching down first. However, as soon as the tailwheel made contact with the runway, the airplane yawed violently to the right. The pilot applied full left rudder and brake control input, but the airplane did not respond, and departed the runway descending down an embankment. The airplane sustained substantial damage to the upper wing spar and fuselage structure at the landing gear attach points.

Postaccident examination revealed that the tailwheel was locked 90 degrees to the right. The tailwheel assembly was disassembled, and the steering arm cam spring appeared jammed between the shaft and housing. The inner surface of the housing exhibited scoring marks, consistent with a pre-existing failure of the spring. The pilot reported that he had purchased the tailwheel assembly used, and that he did not have any records indicating its manufacturer or serial number.

Probable Cause and Findings

The National Transportation Safety Board determines the probable cause(s) of this accident to be:
Failure of the tailwheel steering assembly during maneuvering flight, which resulted in a loss of directional control during the landing roll.

Findings

Aircraft
Directional control - Attain/maintain not possible (Cause)
Landing gear steering system - Failure (Cause)

Factual Information

History of Flight

Maneuvering:  Sys/Comp malf/fail (non-power) (Defining event)
Landing-flare/touchdown: Loss of control on ground
Landing-landing roll:  Runway excursion
  
Pilot Information

Certificate: Airline Transport; Commercial; Flight Engineer
Age:70
Airplane Rating(s): Multi-engine Land; Single-engine Land
Seat Occupied: Single
Other Aircraft Rating(s): None
Restraint Used: 5-point
Instrument Rating(s): Airplane
Second Pilot Present: No
Instructor Rating(s): None
Toxicology Performed: No
Medical Certification: Class 3 Waiver Time Limited Special
Last FAA Medical Exam: 09/10/2014
Occupational Pilot: Yes
Last Flight Review or Equivalent: 06/12/2013
Flight Time:  31293 hours (Total, all aircraft), 690 hours (Total, this make and model), 23909 hours (Pilot In Command, all aircraft), 14.2 hours (Last 90 days, all aircraft), 3.9 hours (Last 30 days, all aircraft)

Aircraft and Owner/Operator Information

Aircraft Manufacturer: WILLIAM M OPRENDEK
Registration: N93DB
Model/Series: PITTS S1S NO SERIES
Aircraft Category: Airplane
Year of Manufacture: 2013
Amateur Built: Yes
Airworthiness Certificate: Experimental
Serial Number: PITTS S1SS-3
Landing Gear Type:  Tailwheel
Seats: 1
Date/Type of Last Inspection: 07/03/2014, Conditional
Certified Max Gross Wt.: 1139 lbs
Time Since Last Inspection: 43.2 Hours
Engines: 1 Reciprocating
Airframe Total Time: 53.1 Hours as of last inspection
Engine Manufacturer: SUPERIOR
ELT: Not installed
Engine Model/Series: XP-IO-360-E1D
Registered Owner: On file
Rated Power: 185 hp
Operator: On file
Operating Certificate(s) Held: None

Meteorological Information and Flight Plan

Conditions at Accident Site: Visual Conditions
Condition of Light: Day
Observation Facility, Elevation: KSEZ, 4830 ft msl
Observation Time: 1535 UTC
Distance from Accident Site: 0 Nautical Miles
Direction from Accident Site: 
Lowest Cloud Condition: Clear
Temperature/Dew Point: 24°C / 9°C
Lowest Ceiling: None
Visibility: 10 Miles
Wind Speed/Gusts, Direction: 3 knots, 80°
Visibility (RVR): 
Altimeter Setting: 30.23 inches Hg
Visibility (RVV): 
Precipitation and Obscuration: No Obscuration; No Precipitation
Departure Point: Sedona, AZ (SEZ)
Type of Flight Plan Filed: None
Destination: Sedona, AZ (SEZ)
Type of Clearance: None
Departure Time:  MST
Type of Airspace: Class E

Airport Information

Airport: SEDONA (SEZ)
Runway Surface Type: Asphalt
Airport Elevation: 4830 ft
Runway Surface Condition: Dry
Runway Used: 03
IFR Approach: None
Runway Length/Width: 5132 ft / 100 ft
VFR Approach/Landing: Traffic Pattern

Wreckage and Impact Information

Crew Injuries: 1 None
Aircraft Damage: Substantial
Passenger Injuries: N/A
Aircraft Fire: None
Ground Injuries: N/A
Aircraft Explosion: None
Total Injuries: 1 None
Latitude, Longitude: 34.848611, -111.788333 (est)