# NTSB WPR12LA414: Cessna T210N, N6493N, Bakersfield, CA, August 17, 2012 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: August 17, 2012, 14:25 local (21:25 UTC) - Place: Bakersfield, CA - Coordinates: 35.433612, -119.057502 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=35.4336&lon=-119.0575&mi=10 - Phase of flight: [Initial climb](https://openairdocs.org/ntsb-phases/350) (OpenAirDocs' grouping) - Defining event: [Initial climb: Loss of engine power (partial)](https://openairdocs.org/ntsb-events/342) - Highest injury: No injuries - Injuries: 3 uninjured - Status: Completed, report June 11, 2014 - Report: Approved by Office Director - NTSB office: Western Pacific Region - Parties: Federal Aviation Administration - NTSB case key (mKey): 85000 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=WPR12LA414 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/85000/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=85000 - Page: https://openairdocs.org/ntsb/WPR12LA414 ## Probable cause A partial loss of engine power during the initial climb due to an in-flight fire of undetermined origin. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Not determined](https://openairdocs.org/ntsb-findings/05000000): Not determined › Not determined · Unknown/Not determined (probable cause); cases with it: [Cessna T210N, 8 cases](https://openairdocs.org/ntsb-findings/05000000/cases.md?model=2073456), [All aircraft, 2,247 cases](https://openairdocs.org/ntsb-findings/05000000/cases.md) - [Power plant](https://openairdocs.org/ntsb-findings/01057100): Aircraft › Aircraft power plant · Failure; cases with it: [Cessna T210N, 1 case](https://openairdocs.org/ntsb-findings/01057100/cases.md?model=2073456), [All aircraft, 198 cases](https://openairdocs.org/ntsb-findings/01057100/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Initial climb: Loss of engine power (partial)](https://openairdocs.org/ntsb-events/342) (defining event); cases with it: [Cessna T210N, 4 cases](https://openairdocs.org/ntsb-events/342/sequence.md?model=2073456), [All aircraft, 1,858 cases](https://openairdocs.org/ntsb-events/342/sequence.md) - [Initial climb: Fire/smoke (non-impact)](https://openairdocs.org/ntsb-events/150); cases with it: [Cessna T210N, 2 cases](https://openairdocs.org/ntsb-events/150/sequence.md?model=2073456), [All aircraft, 504 cases](https://openairdocs.org/ntsb-events/150/sequence.md) ## Analysis Following departure, the pilot banked the airplane to align with the right crosswind of the traffic pattern. He observed smoke entering the cockpit, and the engine began to produce only partial power. The pilot chose to return to the airport, but, due to the power loss, the airplane was unable to reach the runway. The pilot landed the airplane in a field outside the airport's perimeter. The exhaust clamp was found fractured. An area of the fracture appeared flat with granular features, but no clear evidence of preexisting cracks or progressive crack growth was observed. Circumferential cracks were noted in the retainer segments. Although these cracks may have been preexisting, they were not long enough to allow separation of the joint before the band fracture. The exhaust clamp likely fractured due to overstress loading of the joint during the landing. The cause of the in-flight fire could not be determined from the remaining evidence. ## Factual narrative The Cessna T210N, serial number (s/n) 21063067, was manufactured in 1978. The airplane was equipped with a Teledyne Continental Motors TSIO-520R9B engine. A review of the maintenance logbooks revealed that the last annual inspection was dated as having being completed on May 1, 2012 at a tachometer time of 3,931.0 hours. On August 17, 2012, about 1425 Pacific daylight time, a Cessna T210N, N6493N, experienced an in-flight fire shortly after departing from Meadows Field Airport, Bakersfield, California. The airplane was substantially damaged by the fire. The pilot was operating the airplane under the provisions of 14 Code of Federal Regulations (CFR) Part 91. The certified flight instructor and two passengers were not injured. The local personal flight was departing at the time of the accident with a planned destination of Redlands Municipal Airport, Redlands, California. Visual meteorological conditions prevailed, and no flight plan had been filed. The pilot reported that following departure, he banked the airplane to adjoin the right crosswind of the traffic pattern for runway 30R. The pilot observed smoke entering the cockpit and the engine began to only produce partial power. The pilot elected to return back to the airport and configured the airplane for landing on runway 30R. With the degradation of power, he was unable to make it to the runway and landed in a field outside the airport's perimeter. The pilot further stated that the fire was a result of a clamp failure on the turbocharger which is where the origin of the fire appeared to be. The firewall was damaged by fire. The turbocharger clamp pieces were collected and sent to the National Transportation Safety Board Material laboratory for further examination. The V-band exhaust clamp had a 2-segment retainer (''V" portion of the clamp) and was installed on the turbocharger exhaust gas outlet on the accident airplane. The band (flat outer strap) was fractured near the end of the wrap for the t-bolt assembly. Two circumferential cracks were also observed in the retainer extending from the gap opposite from the t-bolt. Each retainer segment contained one circumferential crack. The clamp was generally covered in oxides and sooty deposits. The fracture occurred at the edge of a spot weld attaching the band to the retainer and the fracture surface was on slant planes. Slant-plane fracture features were observed from the edges of the spot weld out to the edges of the band and were consistent with ductile overstress fracture. Reduced width of the band associated with necking deformation was observed adjacent to the fracture. In addition, the edges of the band were deformed radially inward. Similar necking deformation with edges deformed radially inward was observed at the mirror opposite side of the band. In the vicinity of the spot weld, fracture occurred in part in a flat transverse plane. However, slant-plane fracture was also observed at this location. The flat plane fracture was locatednear the middle of the thickness, and a slant fracture was observed near the outer surface. Slant fracture was also observed at the inner edge of the band across most of the spot weld except for an area near the middle of the weld that appeared to have a granular appearance but was not in the transverse plane. A piece of the band containing the t-bolt side of the fracture was separated from the rest of the clamp by cutting the band at the wrap for the t-bolt assembly. The flat fracture region had an intergranular appearance mixed with ductile tear ridges. A piece of the band away from the fracture was cut to facilitate hardness testing. The testing did not reveal any anomalies. No part number or identifying information was found on the v-band clamp. According to the Parts Catalog for the Cessna model 210 and T210 airplanes, one of two part number clamps may be used. ## Aircraft - Registration: [N6493N](https://openairdocs.org/aircraft/N6493N), registered now, S/N 21063067, built 1978 (OpenAirDocs) - Reported make and model: CESSNA T210N - Registry model: [Cessna T210N](https://openairdocs.org/model/cessna-t210n) (registry code 2073456) (OpenAirDocs) - Registry engine: [Continental TSIO-520 series](https://openairdocs.org/engine/continental-tsio-520-series) (registry code 17040, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 21063067 - Airframe hours: 3950 - Engines: CONT MOTOR TSIO-520 SER 300 horsepower reciprocating - Damage: Substantial damage - Fire: In-Flight - Flight: Personal, Part 91 - Airworthiness certificate: Standard, Normal - Last inspection: Annual, May 1, 2012, 19 hours before - Departed: BFL, Bakersfield, CA - Destination: REI, Redlands, CA - Airport: BFL, Meadows Field Airport ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 67; injuries: none; commercial, flight instructor; airplane ratings: multi-engine land, single-engine sea, single-engine land; instrument ratings: airplane; medical: class 2, without waivers/limitations; seat: left; restraint: 3-point; flight hours: 7,396 total, 356 in this make and model, 187 in the last 90 days, 46 in the last 30 days, 4 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 290° at 7 knots - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 95 °F, dew point 45 °F - Altimeter: 29.85 inHg - Observed at: BFL ## 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 20120817020419A](https://openairdocs.org/incident/20120817020419A), Aug 17, 2012: Cessna T210N, Bakersfield, CA, Substantial damage. The exhaust pipe clamp to the turbo broke which allowed the exhaust pipe to rotate inboard. The hot exhaust caused the subsequent fire and resulting damage.… ## Docket (3 files) The files NTSB released with the investigation on May 21, 2014, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=85000. 2.2 MB in all. - Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 394 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40412592&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Redacted.PDF - Engine Logbook Excerpts (item 2, .PDF, 715 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40412593&FileExtension=.PDF&FileName=Engine%20Logbook%20Excerpts-Redacted.PDF - Materials Laboratory 15 - Factual Report 13-068 (item 3, .PDF, 1.1 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40400099&FileExtension=.PDF&FileName=Materials%20Laboratory%2015%20-%20Factual%20Report%2013-068-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.