NTSB Factual Report

HISTORY OF FLIGHT

On July 8, 2011, about 1721 mountain daylight time, a Schweitzer SGS2-32, N591CC, sustained substantial damage when it impacted terrain during takeoff initial climb following a practice low altitude rope release near the Ferndale Airport (53U), Bigfork, Montana. The airline transport rated pilot sustained fatal injuries and the airplane transport rated pilot examiner sustained serious injuries. The glider was registered to and operated by Wave Soaring Adventures Inc., Lake Tapps, Washington, under the provisions of Title 14 Code of Federal Regulations Part 91. Visual meteorological conditions prevailed and no flight plan was filed for the local instructional flight that was originating at the time of the accident.

In a written statement submitted to the National Transportation Safety Board (NTSB) investigator-in-charge (IIC), the pilot examiner reported that the purpose of the flight was to renew the pilot’s flight instructor certificate. He reported that prior to the accident flight; he and the pilot conducted various maneuvers including stalls, steep turns, accelerated stalls, slow flight, and thermal climbs, followed by an uneventful landing on runway 15 as part of the checkride. The examiner stated that after landing, he briefed the tow plane pilot and the pilot receiving the check ride and conveyed that the next flight would be a simulated rope break during takeoff from runway 16. He added that they briefed that the release would be about 260 feet above the ground and that an airspeed of 75 miles per hour (mph) should be maintained during the right turn back to the runway.

The examiner further reported that during the second flight, he released the rope at 260 feet and noticed that the airspeed was slowing. He informed the pilot to increase the airspeed to 75 mph and keep the bank in during the right turn until lined up with runway 33. The examiner stated that before the glider was aligned with runway 33, the pilot made a quick control stick movement to the right, “which caused an accelerated stall.”

Multiple witnesses located adjacent to the accident site reported that they observed the glider depart the airport uneventfully via a tow airplane. As the glider ascended through about 200 to 300 feet, it appeared to release from the tow rope. Shortly after, the glider was observed entering a steep right bank and descended into the ground.

In a written statement, the pilot of the glider tow airplane reported that he departed runway 15. As he ascended through about 200 feet above ground level, he felt the glider release the tow rope. The pilot of the tow plane circled the airport and landed uneventfully.

PERSONNEL INFORMATION

The pilot, who was seated in the rear seat, age 61, held an airline transport pilot rating with airplane multi-engine land ratings, commercial pilot certificate with airplane single-engine land and glider ratings. In addition, the pilot also possessed multiple type ratings in multiple transport category and turbojet aircraft. The pilot also possessed a flight instructor certificate with a glider rating. A second-class airman medical certificate was issued on May 3, 2011, with the limitation “holder shall possess corrective lenses for near.” On his most recent medical certificate application, the pilot reported that he had accumulated 14,760 total flight hours.

The pilot examiner, who was seated in the forward seat, age 68, held an airline transport pilot rating with airplane multi-engine land, airplane single-engine land ratings and a commercial pilot certificate with airplane single-engine sea and glider ratings. In addition, the pilot also possessed multiple type ratings in transport category aircraft. He held a flight instructor certificate with airplane single-engine land, instrument airplane, and glider ratings. A second-class airman medical certificate was issued on July 15, 2010, with a limitation of “must wear corrective lenses.” The pilot examiner reported that he had accumulated 36,500 total flight hours of which 475 hours were in gliders and 35 hours in the accident make/model glider.

AIRCRAFT INFORMATION

The two-seat tandem configuration mid-wing glider, serial number (S/N) 34, was manufactured in 1966. The glider was equipped with dual flight controls for both the front and rear seats. Both of the seats were equipped with lap and shoulder seatbelt restraints. The instrument panel was installed forward of the front seat.

Review of the airframe maintenance logbook revealed that the most recent annual inspection was completed on April 19, 2011, at a total airframe time of 6,450 hours. No historical aircraft records prior to this annual inspection were located.

METEOROLOGICAL INFORMATION

A review of recorded data from the Glacier Park International Airport automated surface observing station, located about 18 miles northwest of the accident site, revealed that at 1655 conditions were wind from 250 degrees at 15 knots, gusts to 30 knots, broken cloud layer at 7,500 feet, broken cloud layer at 9,000 feet, temperature 19 degrees Celsius, dew point 0 degrees Celsius, and an altimeter setting of 29.89 inches of Mercury.

The pilot examiner reported that wind at the time of the accident was from about 235 degrees at 5 knots, gusts to about 8 knots.

AIRPORT INFORMATION

The Ferndale Airfield is an uncontrolled airport surrounded by class G airspace. The reported field elevation is 3,072 feet msl. The airport is equipped with one turf runway (15/33). Runway 15/33 is 3,500 feet in length and 95-feet wide.

WRECKAGE AND IMPACT INFORMATION

Examination of the accident site by a Federal Aviation Administration (FAA) inspector revealed that the glider impacted terrain about 300 feet beyond the departure end of runway 15. The glider came to rest in an upright position and all major structural components were located throughout the wreckage debris path. The FAA inspector stated that control continuity was established throughout the glider to all primary flight control surfaces. Both the left and right wings remained attached to the fuselage. The right wing was partially separated just inboard of the inboard aileron attach point. The right wingtip was separated and located within the wreckage debris path. The forward portion of the fuselage, including the instrument panel was separated from the fuselage and located within the wreckage debris path.

The wreckage was recovered to a secure location for further examination.

MEDICAL AND PATHOLOGICAL INFORMATION

The state medical examiner conducted an autopsy on the pilot on July 8, 2011. The medical examiner determined that the cause of death was “Blunt force injuries...”

The FAA's Civil Aeromedical Institute (CAMI) in Oklahoma City, Oklahoma, performed toxicology tests on the pilot. According to CAMI's report, carbon monoxide, cyanide, volatiles, and drugs were tested, and had positive results of unspecified amounts of amlodipine in the urine and blood, unspecified amounts of atorvastatin in the urine and blood, unspecified amount of fexofenadine in the blood, unspecified amount of ibuprofen in urine, and unspecified amounts of valsartan in the urine and blood.

TESTS AND RESEARCH

Post-accident examination of the glider revealed that the left wing was intact and mostly undamaged. The right wing was impact damaged outboard of the inboard aileron attach point. The right aileron was bent and buckled throughout its span. The vertical stabilizer, rudder, and horizontal stabilator were mostly undamaged. The fuselage was bent and buckled aft of the seating area. The forward area of the fuselage surrounding the front seat exhibited upward and aft crushing. The instrument panel was separated from the fuselage.

The front seat shoulder restraints were light brown in color and the lap restraints were black in color. The front seat shoulder restraint belt was installed, looped around a tubular metal support beam that spanned across the width of fuselage. The tubular beam was bent forward about mid span and partially separated from the right side of the fuselage structure. The shoulder restraint was found separated through the fabric webbings above the chest adjusters.

The rear seat shoulder restraints and lap belts were black in color. The rear seat shoulder restraint was installed by two straps looped around a tubular metal support beam that spanned across the width of the fuselage. The shoulder restraint was found separated at the stitched webbing where the shoulder restraint straps connected to two straps which connected to the tubular metal support beam.

Both the front and rear set shoulder restraints were sent to the National Transpiration Safety Board Materials Laboratory, Washington, DC for further examination.

Examination of the shoulder restraints by a Senior Metallurgist revealed that the front restraints were separated through the fabric webbing above the chest adjusters. No stitching or fitting attachments were apparent in the area. The inside edges of the straps were slightly frayed. The separations were consistent with tensile overstress of both sides with no indications of cutting or sharp edges at the separation locations.

The webbing of the restraints was approximately 1.75 inches wide and had soft and supple texture over the majority of its length. The lengths of webbing below the adjustment buckles were severely worn at the edges. The webbing was stained in several areas, particularly at the “Y” strap length adjuster with rust. The metal fittings on the straps all had a dark oxidized patina with very little surface plating remaining.

No identification markings were present on the restraint.

The rear seat restraint pieces consisted of a yoke with two buckle fittings and chest adjusters and two single straps with loop adjusters but no buckles or end fittings. The restraints were constructed of black 2 inch wide webbing with chrome plated fitting and adjusters. The yoke exhibited a crease and faded pattern at mid length with a few broken threads. Other than the fading and deformation of one buckle latch plate, the yoke appeared to be undamaged.

Both single straps contained a label identifying them as FAA-PMA components manufactured by Aero Fabricators, Lyons, Wisconsin. The model number and date of manufacture were completely faded and unreadable on one strap. The model number on the other strap was discerned as “H702200” with a date of manufacture believed to be “Feb 19, 2004”.

Both of the single straps had a loop with a length adjuster at one end and were folded over themselves and sewn at the other ends. The webbing was intact but the stitching threads were mostly broken at the folded end as if the webbing was pried apart.

A detailed examination report for the front and rear seatbelts is contained in the Materials Laboratory factual report located in the public docket.

NTSB Probable Cause

The pilot’s failure to maintain adequate airspeed and his excessive control inputs during a simulated rope break while taking off, which resulted in an accelerated aerodynamic stall.