SEA03LA050

NTSB accident investigation · Hiperlight SNS-8 · South Prairie, WA · March 25, 2003

Accident · No injuriesLimited investigationFinal report
Date
March 25, 2003, 09:45 local (17:45 UTC)
Place
South Prairie, WA
Injuries
1 uninjured
Damage
Substantial damage
Phase of flight
Maneuvering
Aircraft
UNREGHiperlight SNS-8
Weather
Visual (VMC) · Day
Status
Completed · report November 25, 2003
Report
Approved by Office Director
Parties
FAA FSDO
Case key
56711

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 NTSB’s determination of the probable cause, and any contributing factors.

The failure of the pilot to maintain control of the aircraft during the crosswind turn resulting in an inadvertent spin entry, followed by his intentional stall to a landing resulting in a hard landing and subsequent nose over.

Analysis

The pilot /owner of the unregistered experimental homebuilt SNS-8 aircraft took the aircraft out on its first flight following maintenance work. The pilot reported that the airspeed indicator was inaccurate. After departing the private airstrip, and about 1,300 feet above ground, he attempted to level the wings out of a left turn, but the aircraft continued rolling inverted and the pilot reported that it entered into a spin, which he recovered from after roughly two rotations. The pilot then elected to execute an immediate landing in a nearby field. During his approach, he intentionally slowed the aircraft to stall speed. The aircraft impacted the ground and immediately nosed over. An FAA inspector examined the aircraft and found no malfunction with its flight controls. He also reported finding a leak in the aircraft's pitot static system.

Factual narrative

On March 25, 2003, approximately 0945 Pacific standard time, an unregistered experimental homebuilt SNS-8 aircraft, owned and being flown by a private pilot sustained substantial damage when the aircraft impacted terrain and nosed over during an off airport precautionary landing following a loss of control in flight near South Prairie, Washington. The pilot was uninjured. Visual meteorological conditions prevailed and no flight plan had been filed. The flight, which was personal, was to have been operated under 14 CFR 91, and originated from Cawley's South Prairie private airstrip (02WA) approximately 0930.

The pilot reported that the aircraft had undergone repair work including re-skinning and had been trailered to South Prairie from Oregon on March 24th. The pilot took the aircraft out on its first flight following the maintenance work, departing 02WA and climbing up to approximately 1,300 feet above ground. He reported that when he attempted to level the wings out of the left turn, he could not stop the aircraft from rolling left. The aircraft rolled inverted and the pilot reported that it entered into a spin, which he recovered from after roughly two rotations. Following his recovery he elected to execute an immediate landing in a nearby field and determined that fences and other objects would interfere with the aircraft's landing roll. He then conducted an approach to the field and "...decided to slow to stall speed and ditch at very low alt[itude]...." Upon ground impact the aircraft rolled a short distance and then nosed over (refer to graphic image 1 and 2).

An inspector from the Federal Aviation Administration (FAA) interviewed the pilot (refer to attached statement) and examined the aircraft. He reported finding no malfunction with the flight controls and asked the pilot about his airspeed at the time of the spin entry. The pilot responded that the airspeed indicator was inaccurate and that "...he judged his airspeed by how fast the trees were passing by the aircraft...." An operational check of the aircraft's airspeed indicator by the FAA inspector revealed a leak in the pitot static system.

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.

Loss of control - in flightManeuvering - turn to reverse direction
Aircraft control - not maintainedPilot in commandCause
Hard landingLanding - flare/touchdown
Stall/mush - intentionalPilot in commandCause
Nose overLanding - roll

Aircraft

Registration
UNREG
Reported as
Hiperlight SNS-8
Category
Airplane, amateur-built
Serial number
46
Engine
Rotax 447, 36 horsepower, reciprocating
Damage
Substantial damage
Flight
Personal · Part 91
Registered owner
Kirk, Donald J.
Departed
02WA · South Prairie, WA

Flight crew

As NTSB recorded them. NTSB leaves out names.

Role
Pilot
Age
64
Injuries
None
Certificate
Private
Airplane ratings
Single-engine land
Medical
Class 3, Valid Medical--w/ waivers/lim
Last flight review
March 14, 2003
Seat
Front
Flight hours
426 total · 3 in this make and model

Weather

Conditions
Visual (VMC) · Day
Wind
170° at 6 knots
Visibility
7 statute miles
Lowest ceiling
12,000 ft broken
Temperature
50 °F, dew point 43 °F
Altimeter
30.09 inHg
Observed at
TCM, 16 nm away