# NTSB LAX04LA163: Wallace Skybolt, N41BB, Reno, NV, March 17, 2004 - Type: NTSB accident investigation - Classification: Accident · Serious injuries · Limited investigation · Final report - Date: March 17, 2004, 07:20 local (15:20 UTC) - Place: Reno, NV - Coordinates: 39.692779, -119.961944 - Nearby events: https://openairdocs.org/map.md?lat=39.6928&lon=-119.9619&mi=10 - Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping) - Highest injury: Serious injuries - Injuries: 1 serious - Status: Completed, report July 7, 2005 - Report: Approved by Office Director - Parties: Federal Aviation Administration - NTSB case key (mKey): 58911 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=LAX04LA163 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/58911/pdf - Page: https://openairdocs.org/ntsb/LAX04LA163 ## Probable cause Failure of the left wing spar during an aerobatic maneuver. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Airframe/component/system failure/malfunction, maneuvering - wing,spar - failure,total (cause) - In flight collision with terrain/water, descent - uncontrolled - terrain condition - ground ## Analysis The aircraft broke up in flight while the pilot was executing an aerobatic outside loop maneuver. While inverted and pushing forward on the stick to about -2.5G to start the ascending part of the maneuver, the airplane began to vibrate violently. The pilot felt the vibration in the airframe, not in the stick or the rudder. He felt the vibration for 1 to 2 seconds, followed by the left wing of the airplane detaching from the airplane's structure. During the airplane's continued disintegration, the pilot was able to release his seat belt and exit the airplane. The pilot deployed his parachute, which opened just prior to his reaching the ground. The aircraft was destroyed by a post impact ground fire. The airplane was constructed out of wood in 1975 and, according to the accident airplane's records and the pilot's statement, it had been more than 20 years since the wings had undergone any extensive inspection, repair, or rebuild with the fabric removed. ## Factual narrative On March 17, 2004, about 0720 Pacific standard time, an experimental Wallace Skybolt, N41BB, experienced an in-flight breakup while executing an aerobatic maneuver near Reno/Stead Airport (4SD), Reno, Nevada. The owner/pilot was operating the airplane under the provisions of 14 CFR Part 91. The private pilot, the sole occupant, sustained serious injuries; the airplane was destroyed. The personal local flight departed Stead about 0645. Visual meteorological conditions prevailed, and no flight plan had been filed. The primary wreckage was at 39 degrees 41.34 minutes north latitude and 119 degrees 57.43 minutes west longitude. The Federal Aviation Administration (FAA) accident coordinator responded to the accident scene. He interviewed the pilot on March 25, 2004. The pilot reported that he was executing an aerobatic outside loop maneuver. During the bottom of the loop, while inverted, his airspeed was about 160 mph, and he was about 8,000 feet mean sea level (msl). While pushing forward on the stick to about -2.5G to start the ascending part of the maneuver, the airplane began to vibrate violently. The pilot felt the vibration in the airframe, not in the stick or the rudder. He felt the vibration for 1 to 2 seconds, followed by the left wing of the airplane detaching from the airplane's structure. During the airplane's continued disintegration, the pilot was able to release his seat belt and exit the airplane. The pilot deployed his parachute, which opened just prior to his impacting the ground. The airplane received its original experimental certification in January 1975. Subsequently, the airplane received annual condition inspections. In January 1979, at 307 hours total time, the airplane was disassembled, inspected/repaired, and reassembled/recovered. In March 2000, a larger engine/prop combination was installed. In January 2001, at 733 hours total time, the airframe only was disassembled, inspected, and repaired as necessary, and reassembled/recovered. The wings were not disassembled, inspected, repaired or recovered. According to the accident airplane's records and the pilot's statement, it had been more than 20 years since the wings had undergone any extensive inspection, repair, or rebuild with the fabric removed. ## Aircraft - Registration: [N41BB](https://openairdocs.org/deregistered/N41BB-2007-02-21), registration cancelled 2007-02-21, S/N 1, built 1975 (OpenAirDocs) - Reported make and model: Wallace Skybolt - Registry model: [Wallace SKYBOLT](https://openairdocs.org/model/wallace-skybolt) (registry code 0562651) (OpenAirDocs) - Registry engine: [Lycoming I0360 series](https://openairdocs.org/engine/lycoming-i0360-series) (registry code 41515, reciprocating) (OpenAirDocs) - Category: Airplane, amateur-built - Serial number: 1 - Airframe hours: 815 - Engines: Lycoming IO-540 250 horsepower reciprocating - Damage: Destroyed - Fire: On-Ground - Flight: Personal, Part 91 - Registered owner: Ross W Loudon Trustee - Airworthiness certificate: Special, Experimental (Special) - Last inspection: Condition, June 1, 2003, 65 hours before - Departed: 4SD, Reno, NV - Airport: 4SD, Reno/Stead ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 38; injuries: serious; private; airplane ratings: single-engine land; medical: class 3, valid medical--no waivers/lim.; last flight review July 31, 2002; seat: front; flight hours: 190 total, 49 in this make and model, 144 as pilot in command, 12 in the last 90 days, 7 in the last 30 days, 2 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: calm - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 41 °F, dew point 28 °F - Altimeter: 30.23 inHg - Observed at: RNO, 14 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 (OpenAirDocs). - [Accident 20040317004429A](https://openairdocs.org/incident/20040317004429A), Mar 17, 2004: Amtr SKYBOLT, Reno, NV, Destroyed. (-23) The pilot reported that he was executing an outside loop maneuver. At the bottom of the loop, while inverted at approximately 8,000 feet MSL, the pilot… From the NTSB's public API. Aircraft are matched to registry aircraft by N-number and event date, checked against the reported serial number, make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model. --- OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. Source documents are U.S. government works in the public domain.