# NTSB WPR14LA361: Travel Air C 4000, N9952, Williams, CA, August 30, 2014 - Type: NTSB accident investigation - Classification: Accident · Serious injuries · Limited investigation · Final report - Date: August 30, 2014, 12:21 local (19:21 UTC) - Place: Williams, CA - Coordinates: 39.163612, -122.131668 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=39.1636&lon=-122.1317&mi=10 - Phase of flight: [Initial climb](https://openairdocs.org/ntsb-phases/350) (OpenAirDocs' grouping) - Defining event: [Initial climb: Aircraft structural failure](https://openairdocs.org/ntsb-events/337) - Highest injury: Serious injuries - Injuries: 1 serious - Status: Completed, report March 6, 2017 - Report: Approved by Office Director - NTSB office: Western Pacific Region - Parties: FAA FSDO - NTSB case key (mKey): 89989 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=WPR14LA361 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/89989/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=89989 - Page: https://openairdocs.org/ntsb/WPR14LA361 ## Probable cause The failure of the elevator control tube due to corrosion, which resulted in a loss of elevator control and collision with terrain. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Flight control system: elevator control system](https://openairdocs.org/ntsb-findings/01022730): Aircraft › Aircraft systems · Fatigue/wear/corrosion (probable cause); cases with it: [Travel Air C-4000, 1 case](https://openairdocs.org/ntsb-findings/01022730/cases.md?model=2621822), [All aircraft, 74 cases](https://openairdocs.org/ntsb-findings/01022730/cases.md) - [Performance/control parameters: pitch control](https://openairdocs.org/ntsb-findings/01062022): Aircraft › Aircraft oper/perf/capability · Attain/maintain not possible (probable cause); cases with it: [Travel Air C-4000, 1 case](https://openairdocs.org/ntsb-findings/01062022/cases.md?model=2621822), [All aircraft, 526 cases](https://openairdocs.org/ntsb-findings/01062022/cases.md) - [Use of equip/info: aircraft control](https://openairdocs.org/ntsb-findings/02063040): Personnel issues › Task performance · Pilot; cases with it: [Travel Air C-4000, 1 case](https://openairdocs.org/ntsb-findings/02063040/cases.md?model=2621822), [All aircraft, 9,295 cases](https://openairdocs.org/ntsb-findings/02063040/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Initial climb: Aircraft structural failure](https://openairdocs.org/ntsb-events/337) (defining event); cases with it: [Travel Air C-4000, 1 case](https://openairdocs.org/ntsb-events/337/sequence.md?model=2621822), [All aircraft, 290 cases](https://openairdocs.org/ntsb-events/337/sequence.md) - [Initial climb: Loss of control in flight](https://openairdocs.org/ntsb-events/240); cases with it: [Travel Air C-4000, 1 case](https://openairdocs.org/ntsb-events/240/sequence.md?model=2621822), [All aircraft, 5,002 cases](https://openairdocs.org/ntsb-events/240/sequence.md) ## Analysis A witness reported that during takeoff, the airplane reached about 8 ft above ground level, then suddenly pitched down and descended to ground contact. Postaccident examination of the airplane revealed a fractured and separated elevator control tube. A viscous liquid was inside the fractured tubing. A mixture analysis found signatures for emulsifiers, surfactants, and amines, which are often found in combination in corrosion-inhibiting compounds. The tubing fracture surfaces had features consistent with torsional overstress. A cross-section of the tube away from the fracture was examined. Corrosion was observed on the inner surfaces of the control tube, as well as significant thinning of the control tube wall thickness, which was 1/2 to 2/3 of the thickness of the least-corroded sections. The thinner wall thickness resulting from the corrosion likely could not support the same loading conditions as the full wall thickness, and likely led to the overstress separation of the control tube. ## Factual narrative The pilot did not submit the National Transportation Safety Board Pilot/Operator Aircraft Accident/ Incident Form 6120.1. On August 30, 2014, about 1221 Pacific daylight time, a Travel Air C-4000, N9952, collided with terrain during the takeoff initial climb from the Williams Gliderport, Williams, California. The owner was operating the airplane under the provisions of 14 Code of Federal Regulations (CFR) Part 91. The commercial pilot sustained serious injuries. The airplane sustained substantial damage to the wings and fuselage. The local personal flight was departing. Visual meteorological conditions (VMC) prevailed, and no flight plan had been filed. Witnesses stated that the airplane reached about 8 feet above ground level (agl), and suddenly went nose first into the ground. An examination by a National Transportation Safety Board (NTSB) investigator revealed a fractured and separated control tube for the elevator. The investigator observed a viscous liquid inside the tubing. The tubing was removed for further examination. The tubing was examined by the NTSB Material's Laboratory, and specialists performing exams on the viscous liquid and the tubing itself wrote factual reports, which are in the public docket for this accident. The viscous liquid inside the tubing had hardened into a glossy, gray-beige polymeric solid by the time it reached the laboratory. A sample of it was examined by a Fourier Transform Infrared (FTIR) spectrometer. Spectral peaks corresponded to a nitrogen-hydrogen bond, a carbon-hydrogen stretching bond, a carbon-oxygen double bond (carbonyl), a nitrogen-hydrogen bending bond, and a carbon-hydrogen bending bond. The spectrum suggested that the material contained an amine and a carboxylic acid. A spectrum library search did not identify a match for a single material. A mixture analysis search found signatures for emulsifiers, surfactants, and amines. The combination of these materials are often found in corrosion inhibiting compounds. The tubing fracture surfaces were heavily smeared, and the majority were covered with the same glossy, hard substance that coated the inside of the control tube. The areas of the fracture surfaces minimally covered by the hardened substance were minimally damaged, and had features consistent with overstress. The fracture occurred in a spiral along an approximately 45-degree angle, which was consistent with torsional overstress. A cross-section of the tube away from the fracture was examined. Corrosion was observed on the inner surfaces of the control tube, as well as significant thinning of the control tube wall thickness, which was 1/2 to 2/3 of the wall thickness of the least corroded sections. ## Aircraft - Registration: [N9952](https://openairdocs.org/deregistered/N9952-2018-06-04), registration cancelled 2018-06-04, S/N 1150, built 1929 (OpenAirDocs) - Reported make and model: TRAVEL AIR C 4000 (NO SERIES) - Registry model: [Travel Air C-4000](https://openairdocs.org/model/travel-air-c-4000) (registry code 2621822) (OpenAirDocs) - Registry engine: [Continental W670 series](https://openairdocs.org/engine/continental-w670-series) (registry code 17018, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 1150 - Year built: 1929 - Airframe hours: 5088 - Engines: CONT MOTOR W670 SERIES 250 horsepower reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Airworthiness certificate: Standard, Normal - Departed: CN12, Williams, CA - Destination: CN12, Williams, CA - Airport: CN12, Williams Gliderport, runway 34, 2,500 × 40 ft, asphalt - Equipment: Unknown ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 53; injuries: serious; commercial, airline transport; airplane ratings: multi-engine land, single-engine sea, single-engine land; instrument ratings: airplane; medical: class 2, with waivers/limitations; seat: rear; restraint: lap only; flight hours: 5,000 total, 2 in this make and model ## Weather - Conditions: Visual (VMC), Day - Wind: variable at 3 knots - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 84 °F, dew point 52 °F - Altimeter: 29.87 inHg - Icing: Unknown - Turbulence: Unknown - Observed at: KMYV ## 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 20140830016559A](https://openairdocs.org/incident/20140830016559A), Aug 30, 2014: Travel Air C-4000, Williams, CA, Substantial damage. Pilot reported during takeoff there was a complete loss of control. The aircraft pitched down and impacted the runway. ## Docket (6 files) The files NTSB released with the investigation on January 17, 2017, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=89989. 1.5 MB in all. - NTSB Materials Laboratory Factual Report (item 1, .PDF, 3 photos, 346 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40448307&FileExtension=.PDF&FileName=NTSB%20Materials%20Laboratory%20Factual%20Report-Master.PDF - NTSB Materials Laboratory Report Correspondence Regarding Liquid Substance (item 2, .PDF, 72 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40448308&FileExtension=.PDF&FileName=NTSB%20Materials%20Laboratory%20Report%20Correspondence%20Regarding%20Liquid%20Substance-Master.PDF - Record of Conversation with Owner Rep (item 3, .PDF, 30 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40448309&FileExtension=.PDF&FileName=Record%20of%20Conversation%20with%20Owner%20Rep-Master.PDF - Release of Aircraft Wreckage, NTSB Form 6120.15 (item 4, .PDF, 137 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40448310&FileExtension=.PDF&FileName=Release%20of%20Aircraft%20Wreckage,%20NTSB%20Form%206120.15-Master.PDF - Evidence Control Form - Chain of Custody Control Tubing (item 5, .PDF, 82 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40448311&FileExtension=.PDF&FileName=Evidence%20Control%20Form%20-%20Chain%20of%20Custody%20Control%20Tubing-Master.PDF - Exam Photos (item 6, .PDF, 4 photos, 866 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40448312&FileExtension=.PDF&FileName=Exam%20Photos-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.