# NTSB LAX98LA033: Waco YMF-5, N369DP, Sedona, AZ, November 8, 1997 - Type: NTSB accident investigation - Classification: Accident · Serious injuries · Limited investigation · Final report - Date: November 8, 1997, 12:12 local (19:12 UTC) - Place: Sedona, AZ - Coordinates: 34.940944, -111.939201 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=34.9409&lon=-111.9392&mi=10 - Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping) - Highest injury: Serious injuries - Injuries: 1 serious, 2 minor - Status: Completed, report February 28, 2000 - Report: Approved by Office Director - NTSB case key (mKey): 29993 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=LAX98LA033 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/29993/pdf - Page: https://openairdocs.org/ntsb/LAX98LA033 ## Probable cause The failure and separation of the propeller for undetermined reasons. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Propeller failure/malfunction, cruise - propeller system/accessories - separation (cause) - reason for occurrence undetermined (cause) - Forced landing, emergency descent/landing - terrain condition - none suitable - In flight collision with terrain/water, emergency descent/landing - terrain condition - mountainous/hilly ## Analysis The pilot reported that during the preflight inspection, he examined the propeller while pulling the engine through each cylinder and found no discrepancies. The aircraft was about 7 minutes into a 15-minute flight when he saw a 'spark or flash' at the 11 o'clock position on the nose, followed quickly by the complete separation of the propeller. He turned the aircraft back toward the airport but had insufficient altitude and landed in a hilly area of a canyon. A postcrash fire began and consumed the aircraft aft of the firewall. The aircraft was examined on site and following recovery of the wreckage. An unsuccessful search was made for the wooden propeller. The metal propeller hub remained attached to the engine crankshaft with fragments of the wood center section intertwined in the bolts. The wood remains were insufficient to determine either the model or serial number of the propeller, or the condition of the boltholes. Both the engine crankshaft splines and propeller hub splines were unremarkable. The remaining pieces of wood from the hub were submitted for laboratory evaluation. The examining laboratories reported that there was insufficient evidence available from the small fragments submitted to identify an initiating event in the propeller or the failure cause of the wood hub. ## Factual narrative On November 8, 1997, at 1212 hours mountain standard time, a Waco YMF-5, N369DP, sustained an in-flight separation of the propeller during cruise flight and forced landed on a hillside near the mouth of Oak Creek Canyon in Sedona, Arizona. The aircraft was owned by Red Rock Biplane Tours and was being operated on a 14 CFR Part 91 local area for-hire sightseeing flight. The aircraft was destroyed during the impact sequence and postcrash fire. The commercial pilot and one passenger sustained minor injuries; however, the remaining passenger sustained serious injuries. Visual meteorological conditions prevailed. In written and verbal statements, the pilot reported that after greeting the passengers who were to take this tour, he inspected the aircraft. During the inspection, he examined the propeller while pulling the engine through each cylinder and found no discrepancies. The aircraft was about 7 minutes into a 15-minute flight when he saw a "spark or flash" at the 11 o'clock position on the nose, followed quickly by the complete separation of the propeller. He turned the aircraft back toward the airport but had insufficient altitude and landed in a hilly area of a canyon. A postcrash fire began and consumed the aircraft aft of the firewall. The aircraft was examined on site and following recovery of the wreckage. An unsuccessful search was made for the wooden propeller. The metal propeller hub remained attached to the engine crankshaft with fragments of the wood center section intertwined in the bolts. The wood remains were insufficient to determine either the model or serial number of the propeller, or the condition of the boltholes. Both the engine crankshaft splines and propeller hub splines were unremarkable. The remaining pieces of wood from the hub were submitted to the Sensenich Wood Propeller Company, Borden Chemical Company (manufacturer of the glue), and to the U.S. Department of Agriculture's Forest Products Laboratory for evaluation. Reports of the examinations are attached. The glue bond quality was found to be consistent with the manufacturer's instructions. The remaining fragments were not large enough to conduct a meaningful shear strength evaluation. According to the Forest Products Laboratory report, evidence of hub overheating was found in the fragments submitted. No failures were identified in the glue bond lines. The report notes that excessive heat induces a loss of strength in the wood fibers. The varnished face of the hub was not flat, and was not making full contact with the metal hub retainer plate. In conclusion, the report stated that there was insufficient evidence available from the small fragments submitted to connect the noted defects with an initiating event in the propeller or the failure of the wood hub. The aircraft maintenance records were examined for entries pertaining to the propeller. The last logbook entry concerning installation of a propeller was dated June 22, 1994, and documented the installation of Sensenich wood propeller model W96JA-4-68, serial number AB7725. The next entry dated August 1, 1996, noted the removal and replacement of eight propeller hub bolts and nuts. An invoice from General Aviation, Inc., was supplied by the operator documenting the purchase of propeller W96JA-4-68, serial number AC8560, on October 30, 1996. The operator stated that this propeller was installed on the accident aircraft on November 8, 1996; however, no logbook entry to this effect was found. ## Aircraft - Registration: [N369DP](https://openairdocs.org/deregistered/N369DP-1998-06-12), registration cancelled 1998-06-12, S/N F5007 (OpenAirDocs) - Reported make and model: Waco YMF-5 - Registry model: [Waco YMF](https://openairdocs.org/model/waco-ymf) (registry code 9600411) (OpenAirDocs) - Category: Airplane - Serial number: 007 - Airframe hours: 1080 - Engines: Jacobs R755B2 275 horsepower reciprocating - Damage: Destroyed - Fire: On-Ground - Flight: Business, Part 91 - Registered owner: Dakota Territory Tours Inc. - Airworthiness certificate: Standard, Normal - Last inspection: 100 hour, October 31, 1997, 18 hours before - Departed: SEZ ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 29; flight instructor, commercial; airplane ratings: single-engine land, single-engine sea, multi-engine land; instrument ratings: airplane; medical: class 1, valid medical--no waivers/lim.; seat: rear; flight hours: 4,700 total, 1,600 in this make and model, 4,600 as pilot in command, 148 in the last 90 days, 82 in the last 30 days, 5 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 200° at 15 knots, gusting 19 - Visibility: 50 statute miles - Lowest ceiling: none - Temperature: 54 °F, dew point 25 °F - Altimeter: 30.00 inHg - Observed at: FLG, 42 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 19971108032649A](https://openairdocs.org/incident/19971108032649A), Nov 8, 1997: Waco YMF, Sedona, AZ, Destroyed. Sightseeing flight. Prop assembly seperated. Crash landed. (From .4) the pilot reported that during the preflight inspection, he examined the propeller while… ## Other investigations on N369DP (1) 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. - [NTSB CHI94LA030](https://openairdocs.org/ntsb/CHI94LA030), Nov 2, 1993: Waco YMF-5 (N369DP), Valparaiso, IN, substantial damage. Probable cause: THE PILOT'S INADEQUATE COMPENSATION FOR WIND CONDITIONS WHILE LANDING IN A GUSTY CROSSWIND. FACTORS ASSOCIATED WITH THE ACCIDENT ARE THE GUSTY CROSSWIND AND THE PILOT'S LACK OF EXPERIENCE IN THIS… 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.