# NTSB WPR17LA144: Cessna U206F, N71001, Page, AZ, June 23, 2017 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: June 23, 2017, 16:00 local (23:00 UTC) - Place: Page, AZ - Coordinates: 36.913318, -111.45609 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=36.9133&lon=-111.4561&mi=10 - Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping) - Defining event: [Enroute-cruise: Powerplant sys/comp malf/fail](https://openairdocs.org/ntsb-events/340) - Highest injury: No injuries - Injuries: 6 uninjured - Status: Completed, report April 13, 2020 - Report: Approved by Office Director - NTSB office: Western Pacific Region - Parties: Federal Aviation Administration - NTSB case key (mKey): 95521 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=WPR17LA144 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/95521/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=95521 - Page: https://openairdocs.org/ntsb/WPR17LA144 ## Probable cause The failure of the throttle control cable due to fatigue and maintenance personnel’s failure to replace the cable at the last engine overhaul, which resulted in the pilots’ inability to control engine power and led to a precautionary landing during which the airplane impacted bushes. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Engine controls: power lever](https://openairdocs.org/ntsb-findings/01057603): Aircraft › Aircraft power plant · Fatigue/wear/corrosion (probable cause); cases with it: [Cessna U206F, 1 case](https://openairdocs.org/ntsb-findings/01057603/cases.md?model=2073333), [All aircraft, 95 cases](https://openairdocs.org/ntsb-findings/01057603/cases.md) - [Engine controls: power lever](https://openairdocs.org/ntsb-findings/01057603): Aircraft › Aircraft power plant · Failure (probable cause); cases with it: [Cessna U206F, 1 case](https://openairdocs.org/ntsb-findings/01057603/cases.md?model=2073333), [All aircraft, 95 cases](https://openairdocs.org/ntsb-findings/01057603/cases.md) - [Engine controls: power lever](https://openairdocs.org/ntsb-findings/01057603): Aircraft › Aircraft power plant · Incorrect service/maintenance (probable cause); cases with it: [Cessna U206F, 1 case](https://openairdocs.org/ntsb-findings/01057603/cases.md?model=2073333), [All aircraft, 95 cases](https://openairdocs.org/ntsb-findings/01057603/cases.md) - [Maintenance: replacement](https://openairdocs.org/ntsb-findings/02062020): Personnel issues › Task performance · Maintenance personnel (probable cause); cases with it: [Cessna U206F, 2 cases](https://openairdocs.org/ntsb-findings/02062020/cases.md?model=2073333), [All aircraft, 70 cases](https://openairdocs.org/ntsb-findings/02062020/cases.md) - [Action: lack of action](https://openairdocs.org/ntsb-findings/02041030): Personnel issues › Action/decision · Maintenance personnel (probable cause); cases with it: [Cessna U206F, 2 cases](https://openairdocs.org/ntsb-findings/02041030/cases.md?model=2073333), [All aircraft, 792 cases](https://openairdocs.org/ntsb-findings/02041030/cases.md) - [Object/animal/substance](https://openairdocs.org/ntsb-findings/03022000): Environmental issues › Physical environment · Effect on operation (probable cause); cases with it: [Cessna U206F, 1 case](https://openairdocs.org/ntsb-findings/03022000/cases.md?model=2073333), [All aircraft, 224 cases](https://openairdocs.org/ntsb-findings/03022000/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Enroute-cruise: Powerplant sys/comp malf/fail](https://openairdocs.org/ntsb-events/340) (defining event); cases with it: [Cessna U206F, 1 case](https://openairdocs.org/ntsb-events/340/sequence.md?model=2073333), [All aircraft, 820 cases](https://openairdocs.org/ntsb-events/340/sequence.md) - [Enroute-cruise: Loss of engine power (total)](https://openairdocs.org/ntsb-events/341); cases with it: [Cessna U206F, 5 cases](https://openairdocs.org/ntsb-events/341/sequence.md?model=2073333), [All aircraft, 3,820 cases](https://openairdocs.org/ntsb-events/341/sequence.md) - [Uncontrolled descent: Attempted remediation/recovery](https://openairdocs.org/ntsb-events/060); cases with it: [Cessna U206F, 2 cases](https://openairdocs.org/ntsb-events/060/sequence.md?model=2073333), [All aircraft, 1,422 cases](https://openairdocs.org/ntsb-events/060/sequence.md) - [Landing: Off-field or emergency landing](https://openairdocs.org/ntsb-events/440); cases with it: [Cessna U206F, 5 cases](https://openairdocs.org/ntsb-events/440/sequence.md?model=2073333), [All aircraft, 3,365 cases](https://openairdocs.org/ntsb-events/440/sequence.md) - [Landing: Collision with terr/obj (non-CFIT) ](https://openairdocs.org/ntsb-events/470); cases with it: [Cessna U206F, 12 cases](https://openairdocs.org/ntsb-events/470/sequence.md?model=2073333), [All aircraft, 10,189 cases](https://openairdocs.org/ntsb-events/470/sequence.md) ## Analysis The commercial pilot, who was the pilot flying, reported that, while he, the copilot, and four passengers were returning to the airport following a sightseeing flight and while the airplane was at 7,500 ft, it would no longer climb. The airplane then slowly started to descend about 350 ft per minute. Unable to stop the descent, the pilots attempted to troubleshoot the problem but were unable to regain engine power. The pilot initiated a precautionary landing onto a dirt road. When the airplane was about 125 ft above ground level, the copilot took control of the airplane and landed it on the road. During the landing roll, the left wing impacted bushes before coming to rest. As the pilots retarded the throttle to idle, the throttle and about 2 ft of the throttle control cable came out of the control panel. Metallurgical examination of the throttle cable wires revealed flat fracture surfaces that were perpendicular to the wires' axes, and no evidence of necking or other deformation was found, which is consistent with a progressive fracture mechanism, such as fatigue. Therefore, the throttle control cable likely failed due to fatigue and resulted in the pilots' inability to control the engine power. A review of the airplane's maintenance logbooks revealed that the throttle control cable was installed more than 20 years before the accident. The airplane maintenance manual indicated that the engine controls, including the throttle control cable, should be replaced at every engine overhaul. The operator reported that the last engine overhaul was completed 163 hours before the accident. The logbooks did not indicate that the throttle control cable had been replaced during the overhaul. Given the evidence, maintenance personnel likely failed to replace the throttle control cable at the last engine overhaul, which led to the cable fracturing in flight due to fatigue and the subsequent inability of the pilots to control the engine power. ## Factual narrative On June 23, 2017, about 1600 mountain standard time, a Cessna U206F airplane, N71001, sustained substantial damage after the pilot executed a precautionary landing about 28 miles southeast of Page, Arizona. The two commercial pilots and four passengers were not injured. The airplane was registered to, and operated by, American Aviation Inc. as a Title 14 Code of Federal Regulations Part 135 scenic flight. Visual meteorological conditions prevailed at the time of the accident and a company visual flight rules flight plan had been filed. The flight originated from Page, Arizona at an unknown time. The pilot in command (PIC) reported that while they were returning to the airport at 7,500 ft, the airplane would no longer climb; it then slowly started to descend at about 350 ft per minute. Unable to stop the descent, the pilots attempted to troubleshoot the problem, but were not able to restore engine power. The PIC initiated a precautionary landing onto a dirt road. About 125 ft above the ground, the co-pilot took control of the airplane and landed softly onto the road. During the landing roll, the airplane's left wing impacted juniper bushes before it came to rest. As the pilots retarded the throttle to idle, the throttle came out of the control panel along with about two ft of the throttle cable. During a postaccident examination by a Federal Aviation Administration inspector, it was noted that the throttle control cable separated from the rod end of the throttle body control. Review of the maintenance logs indicated the throttle cable was last installed in 1996. The throttle cable, to include the rod end, and rod end sleeve were removed from the airplane and sent to the National Transportation Safety Board (NTSB) Materials Laboratory for further examination. The NTSB Materials Laboratory reported that digital microscope images of the rod end, which was within the rod end sleeve, exhibited two circumferential bands of wear on the ends. The bands were heavier on one side of the pieces, and the band closest to the end had less damage compared to the other band. Corresponding wear was observed on the inner surface of the mating guide piece. The wire strands were observed, and the fracture surfaces were flat and perpendicular to the axes of the strands. No necking or thinning of the individual strands consistent with overstress separation was observed. Cessna Maintenance Manual indicates that the engine controls and linkages should be examined "each 50 hours for general condition and freedom of movement. These controls are not repairable. Replace throttle, propeller, and mixture controls at each engine overhaul." The operator reported the airplane's annual inspection was completed about 43 hours prior to the accident, and the overhaul 163 hours prior to the accident. The logbooks did not show that the cable had been replaced. ## Aircraft - Registration: [N71001](https://openairdocs.org/deregistered/N71001-2019-04-09), registration cancelled 2019-04-09, S/N U20602115, built 1973 (OpenAirDocs) - Reported make and model: CESSNA U206F - Registry model: [Cessna U206F](https://openairdocs.org/model/cessna-u206f) (registry code 2073333) (OpenAirDocs) - Registry engine: [Continental IO-520 series](https://openairdocs.org/engine/continental-io-520-series) (registry code 17032, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: U20602115 - Year built: 1973 - Airframe hours: 9970 - Engines: Continental IO-520 LCF 300 horsepower reciprocating - Damage: Substantial damage - Flight: Part 135 - Operator: American Aviation Inc - Registered owner: American Aviation Inc - Airworthiness certificate: Standard, Normal - Last inspection: 100 hour, June 1, 2017, 43 hours before - Departed: PGA, Page, AZ - Destination: PGA, Page, AZ - Flight plan: Company VFR ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 37; injuries: none; commercial; airplane ratings: single-engine land; instrument ratings: airplane; medical: class 1, with waivers/limitations; last flight review June 4, 2017; seat: left; restraint: 3-point; flight hours: 535 total, 15 in this make and model, 285 as pilot in command, 15 in the last 30 days - Co-pilot; age 27; injuries: none; commercial; airplane ratings: multi-engine land, single-engine land; instrument ratings: airplane; medical: class 2, without waivers/limitations; last flight review March 16, 2017; seat: right; restraint: 3-point; flight hours: 685 total, 35 in the last 90 days, 10 in the last 30 days ## Weather - Conditions: Visual (VMC), Day - Wind: 250° at 6 knots, gusting 15 - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 102 °F, dew point 30 °F - Altimeter: 29.92 inHg - Observed at: PGA, 28 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 20170623008609A](https://openairdocs.org/incident/20170623008609A), Jun 23, 2017: Cessna U206F, Page, AZ, Substantial damage. Pilot was on return flight to Page Municipal Airport from monument valley air tour. Pilot reported aircraft inability to climb. Started slow descent rate of… ## Other investigations on N71001 (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 DEN88IA204](https://openairdocs.org/ntsb/DEN88IA204), Sep 15, 1988: Cessna 206 (N71001), Glade Park, CO, incident, no damage. Probable cause: THE FAILURE OF THE #1 CONNECTING ROD ASSEMBLY IN THE ENGINE, RESULTING IN A FORCED LANDING. A FACTOR IN THE INCIDENT WAS THAT THE PILOT DID NOT SEE & AVOID POWER WIRES IN THE FORCED LANDING PATH. ## Docket (4 files) The files NTSB released with the investigation on January 16, 2020, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=95521. 1.9 MB in all. - Materials Laboratory Factual Report (item 1, .PDF, 709 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40479998&FileExtension=.PDF&FileName=Materials%20Laboratory%20Factual%20Report-Master.PDF - Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 2, .PDF, 459 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40479999&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Master.PDF - Record of Conversation - Federal Aviation Administration Inspector (item 3, .PDF, 386 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40480000&FileExtension=.PDF&FileName=Record%20of%20Conversation%20-%20Federal%20Aviation%20Administration%20Inspector-Master.PDF - Cessna Maintenance Manual Excerpt (item 4, .PDF, 362 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40480001&FileExtension=.PDF&FileName=Cessna%20Maintenance%20Manual%20Excerpt-Master.PDF 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.