# NTSB DEN93LA069: Irving Siewert Osprey GP-4, N85Z, Canon City, CO, June 25, 1993 - Type: NTSB accident investigation - Classification: Accident · Fatal · Limited investigation · Final report - Date: June 25, 1993, 09:30 local (15:30 UTC) - Place: Canon City, CO - Location: 38.4419° N, 105.2209° W: Placed by OpenAirDocs: center of Cañon City, CO, within about 6 miles (OpenAirDocs) - Nearby events: https://openairdocs.org/map.md?lat=38.4419&lon=-105.2209&mi=10 - Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping) - Highest injury: Fatal - Injuries: 1 fatal - Status: Completed, report September 13, 1994 - Report: Approved by Office Director - NTSB case key (mKey): 11089 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=DEN93LA069 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/11089/pdf - Page: https://openairdocs.org/ntsb/DEN93LA069 ## Probable cause FAILURE BY THE PILOT/BUILDER TO FOLLOW CONSTRUCTION SPECIFICATIONS AND THE USE OF IMPROPER MATERIALS DURING CONSTRUCTION OF THE AIRCRAFT. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Airframe/component/system failure/malfunction, cruise - normal - window,canopy - separation - material inadequate,improper, manufacturer (cause) - Loss of control - in flight, descent - uncontrolled - horizontal stabilizer surface - separation - vertical stabilizer surface - separation - In flight collision with object, descent - uncontrolled - object - tree(s) ## Analysis WHILE ON A LOCAL AREA FLIGHT, THE AIRCRAFT BROKE UP IN FLIGHT WITH THE CANOPY AND HORIZONTAL/VERTICAL STABILIZER SEPARATING FROM THE AIRCRAFT. REVIEW OF DESIGN SPECIFICATION PROVIDED INFORMATION THAT THE PILOT/BUILDER HAD USED A NON STANDARD CANOPY LATCH AND CONSTRUCTED THE WINDSHIELD BOW FROM FIBERGLASS VICE THE ALUMINUM MATERIAL REQUIRED. THE CANOPY CAME OFF IN FLIGHT AND STRUCK THE LEFT HORIZONTAL STABILIZER CAUSING THE HORIZONTAL AND VERTICAL STABILIZER TO SEPARATE FROM THE AIRCRAFT. ## Factual narrative On June 25, 1993, at approximately 0930 mountain daylight time, an Osprey GP-4, N85Z, experimental homebuilt aircraft, had an airframe in flight failure while in cruise flight approximately 15 miles northeast of Canon City, Colorado. The commercial certificated pilot, who was the builder, received fatal injuries and the aircraft was destroyed. Visual meteorological conditions prevailed for this local personal flight which departed Canon City at 0915. No flight plan was filed. Examination of the accident site provided information on wreckage distribution and a wreckage distribution diagram is attached. The scatter pattern was oriented on a base course of 270 degrees and the canopy was the first item in the wreckage distribution pattern. Approximately 400 yards beyond the canopy, the tail section was found and 200 yards further along the elevator control rods and the pilot's headset were found. The main wreckage was located approximately 1400 yards from the canopy. Detailed examination of the canopy provided information that the canopy latch was separated from the canopy and the retention screws had pulled out of the mounting structure. The cross brace located in the rear of the canopy was fractured and indentation marks on the canopy edge were present. The vertical and horizontal stabilizer were separated from each other and the left horizontal stabilizer had indentations which matched the damage found on the canopy edge. The stabilizers pulled free from the empennage in a rearward direction and the wood structure provided evidence of longitudinal overload. The fuselage, wings, and engine impacted into cedar trees which varied in height from 8 to 12 feet. The wooden structure disintegrated upon impacted into several sections, and the engine remained attached to the mounts. The propeller remained attached to the engine. One blade was bent rearward eight inches inboard from the tip. The other blade contained an 'S' curve along its span and incurred leading edge gouging and chordwise scratches. Detailed aircraft specifications were obtained from the designer and discussions were held with him as regards various canopy design and structural elements. Review of this material provided information that the canopy latch was of the trunk type and did not match the required design specifications. In addition, it was found that the canopy hold down faring was constructed from a light fiberglass material vice the .050 aluminum material in the design specifications. Review of available information provided information that these specifications are required due to the canopy lift co-efficient at 200 mph which is approximately 50 psi. Details of GP-4 design and construction are attached. ## Aircraft - Registration: [N85Z](https://openairdocs.org/deregistered/N85Z-1995-05-22), registration cancelled 1995-05-22, S/N 125 (OpenAirDocs) - Reported make and model: IRVING SIEWERT OSPREY GP-4 (OSPREY GP-) - Registry model: [Siewert Irving OSPREY GP-4](https://openairdocs.org/model/siewert-irving-osprey-gp-4) (registry code 95708CR) (OpenAirDocs) - Category: Airplane, amateur-built - Serial number: 125 - Airframe hours: 8 - Engines: LYCOMING IO 360-A1A 200 horsepower reciprocating - Damage: Destroyed - Flight: Personal, Part 91 - Registered owner: Irving Siewert - Airworthiness certificate: Special, Experimental (Special) - Last inspection: Annual, January 1, 1993, 8 hours before ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 62; private, commercial; airplane ratings: single-engine land, multi-engine land; instrument ratings: airplane; medical: class 3, valid medical--w/ waivers/lim; seat: left; toxicology performed; flight hours: 4,500 total, 8 in this make and model ## Weather - Conditions: Visual (VMC), Day - Wind: 330° at 5 knots - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 72 °F, dew point 39 °F - Altimeter: 30.00 inHg - Observed at: PUB, 15 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 19930625020439A](https://openairdocs.org/incident/19930625020439A), Jun 25, 1993: Ogden OSPREY, Canon City, CO, Destroyed, 1 fatal. Broke up inflight. Canopy horizontal stabilizer separated. Bogas latch and plexiglass used. Canopy hit stabilizer. 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.