LAX00LA068

NTSB accident investigation · Clark Pitts S1X · Upland, CA · January 8, 2000

Accident · FatalLimited investigationFinal report
Date
January 8, 2000, 10:34 local (18:34 UTC)
Place
Upland, CA
Injuries
1 fatal
Damage
Destroyed
Phase of flight
Maneuvering
Aircraft
N900SHClark Pitts S1X
Weather
Visual (VMC) · Day
Status
Completed · report January 2, 2002
Report
Approved by Office Director
FAA report
20000108000909A
Case key
48461

From the NTSB’s public API. By law, NTSB reports can’t be used as evidence in lawsuits over the accident.

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Probable cause

The pilot's failure to recover from an intentional aerobatic maneuver.

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.

In flight collision with terrain/waterManeuvering
Aerobatics - performedPilot in command
Stall/spin - not correctedPilot in commandCause

Analysis

During an air show, while conducting aerobatic maneuvers, the airplane continued in a spin to ground impact. According to witnesses, the pilot was performing an aerobatic routine with two other airplanes, known as a "squirrel cage" maneuver. The airplanes would take turns entering the aerobatic box to perform a single choreographed maneuver. The routine card indicated that the pilot was to perform multiple snap rolls when the accident occurred. A video of the pilot's routine was examined with the assistance of members of the International Aerobatic Club. The video showed that the pilot made 3 1/2 snap rolls to the right, and then 2 1/2 spins to the left. It appeared there was no flight control problem and the pilot entered a flat spin. The elevator appeared to be loaded and the pilot never broke the stall prior to impact. The pilot had written a magazine article advocating a specific spin recovery method.

Factual narrative

On January 8, 2000, at 1034 hours Pacific standard time, a homebuilt Pitts S1X, N900SH, collided with terrain while performing an aerobatic routine at an airshow at the Cable Airport, Upland, California. The experimental airplane, owned and operated by the pilot, was destroyed. The commercial pilot was fatally injured. The local airshow performance, conducted under 14 CFR Part 91, had originated at the Cable Airport at an unspecified time. Visual meteorological conditions prevailed and no flight plan was filed.

According to witnesses, the pilot was performing an aerobatic routine with two other airplanes, known as a "squirrel cage" maneuver. The airplanes would take turns entering the aerobatic box to perform a single choreographed maneuver. The airshow held a waiver for an "airshow box" (performing area), which was partly over a rock quarry. The routine card indicated that the pilot was supposed to perform multiple snap rolls when the accident occurred.

A video of the pilot's routine was provided to the Safety Board. A frame-by-frame examination was conducted, with the assistance of the International Aerobatic Club. The video showed that the pilot made 3 1/2 snap rolls to the right, then 2 1/2 spins to the left. The elevator appeared to be loaded. The video cut out as the pilot impacted the rock quarry. Witnesses reported that there was a fire on impact. No one on the ground was injured.

According to the Federal Aviation Administration (FAA) airman certification database, the pilot held an airline transport pilot certificate with an airplane multiengine land rating. He also held a commercial pilot certificate with an airplane single engine land rating and a private certificate with a helicopter rating.

The FAA aeromedical certification database revealed that the pilot held a second-class medical, issued March 11, 1999, with the restriction that the pilot must wear corrective lenses.

The aircraft was examined following its recovery from the impact site. The flight controls were inspected. Both rudder pedals remained secured at their respective fittings. Both rudder cables were fractured approximately midspan. The fractured cables displayed frayed ends, and "necking" was evident when viewed under a magnifying lens. The elevator trim was intact and secure at its fitting. The elevator control system was separated at a joint fitting. It remained connected forward of the stick to just aft of the seat. Both the right and left side top and bottom ailerons both moved freely with no noted binding. The right side aileron control system was fractured at the bellcrank joint. The left side aileron control system was fractured at a joint fitting.

No foreign objects were found in any of the control system surfaces. All controls could be manipulated freely by hand.

Examination of the engine revealed significant thermal damage. The propeller could not be rotated by hand. The top and bottom spark plugs were removed and examined. They exhibited normal coloration and wear patterns consistent with the Champion Check-A-Plug chart. The magnetos, fuel pump, and sections of the fuel injection servo displayed significant damage and no testing was conducted. The cylinders were internally examined utilizing a lighted bore scope; they appeared undamaged. The valves were intact and there was no evidence of foreign object ingestion or oil residue. The fuel injector(s) remained at their respective locations with the fuel lines attached. The rocker box covers were removed. The rocker assemblies, springs, and valve retainers were secure at each cylinder assembly. There was no evidence of metal contamination observed at the rockers or oil screen. The oil cooler bypass valve (vernatherm) remained intact. The fuel injection servo fuel inlet screen was removed and displayed no visible contaminants. The oil sump and portions of the accessory case had been displaced, exposing portions of the crankshaft and accessory gears. Visual inspection of the internal components through those voids utilizing a lighted bore scope revealed no evidence of malfunction. There was no evidence of mechanical malfunction.

According to the pilot's ACE, the pilot had not been approved for squirrel cage maneuvers. The pilot held a "level 3" certificate, and according to the ACE, at level 3, any deviations from the planned routine should be approved. He had only approved the pilot for his usual routine.

Aircraft

Registration
N900SH
Reported as
Clark Pitts S1X
Category
Airplane, amateur-built
Serial number
001
Airframe hours
395
Engine
Lycoming AEIO-360, 180 horsepower, reciprocating
Damage
Destroyed
Fire
On-Ground
Flight
Part 91
Registered owner
Mark Madden
Airworthiness certificate
Special, Experimental (Special)
Last inspection
Annual · December 6, 1999
Departed
CCB
Airport
CCB · Cable

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
40
Certificates
Private, Airline transport, Commercial
Airplane ratings
Multi-engine land, Single-engine land
Instrument ratings
Airplane
Medical
Class 2, Valid Medical--w/ waivers/lim
Seat
Front
Toxicology
Performed
Flight hours
2,600 total

Weather

Conditions
Visual (VMC) · Day
Visibility
10 statute miles
Temperature
131 °F, dew point 77 °F
Altimeter
30.00 inHg
Observed at
ONT, 5 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.