# NTSB CEN11LA357: Cessna T210M, N6850B, Pueblo, CO, May 21, 2011 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: May 21, 2011, 10:25 local (16:25 UTC) - Place: Pueblo, CO - Coordinates: 38.286666, -104.491111 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=38.2867&lon=-104.4911&mi=10 - Phase of flight: [Landing](https://openairdocs.org/ntsb-phases/550) (OpenAirDocs' grouping) - Defining event: [Landing: Landing gear collapse](https://openairdocs.org/ntsb-events/094) - Highest injury: No injuries - Injuries: 1 uninjured - Status: Completed, report February 6, 2012 - Report: Approved by Office Director - NTSB office: Central Region - Parties: FAA/FSDO - NTSB case key (mKey): 79233 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CEN11LA357 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/79233/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=79233 - Page: https://openairdocs.org/ntsb/CEN11LA357 ## Probable cause Failure of the landing gear to fully extend due to a failed o-ring in the nose gear actuator piston and a broken seal in the emergency landing gear extension system. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Landing gear system: landing gear actuator](https://openairdocs.org/ntsb-findings/01023233): Aircraft › Aircraft systems · Failure (probable cause); cases with it: [Cessna T210M, 4 cases](https://openairdocs.org/ntsb-findings/01023233/cases.md?model=2073451), [All aircraft, 54 cases](https://openairdocs.org/ntsb-findings/01023233/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Landing: Landing gear collapse](https://openairdocs.org/ntsb-events/094) (defining event); cases with it: [Cessna T210M, 7 cases](https://openairdocs.org/ntsb-events/094/sequence.md?model=2073451), [All aircraft, 1,787 cases](https://openairdocs.org/ntsb-events/094/sequence.md) ## Analysis The pilot heard an unusual sound as he retracted the landing gear after takeoff and the amber gear warning light was illuminated. The pilot referenced the emergency procedures and made two unsuccessful attempts to manually extend the gear. After engaging the autopilot, the pilot then checked the hydraulic reservoir in the cockpit and it was empty. At the advice of an air traffic controller, the pilot added a quart of engine oil in the hydraulic reservoir and attempted another manual gear extension. The pilot was still unable to extend the gear. The pilot made a low pass by the control tower and a controller informed him that no landing gear were visible. The pilot then made a gear-up landing as directed by the Pilot Operating Handbook; however, according to airport personnel, the pilot landed with the nose gear down and the main landing gear retracted. The airplane skidded on its belly and the left horizontal stabilizer was damaged. According to a representative of the repair facility that fixed the airplane, an o-ring in the nose gear actuator piston had failed. In addition, a seal in the emergency extension system had also failed. Once the failed o-ring and seal were replaced, the landing gear functioned normally. ## Factual narrative On May 21, 2011, at 1025 mountain daylight time, N6850B, a Cessna T210M, was substantially damaged during a gear up landing at Pueblo Memorial Airport (PUB), Pueblo, Colorado. The commercial pilot was not injured. The airplane was registered to and operated by the pilot. Visual meteorological conditions prevailed and no flight plan was filed for the personal flight conducted under 14 Code of Federal Regulations Part 91. According to the pilot, he departed Pueblo to conduct air work in the local area. After a normal take off, when the landing gear was retracted, he heard a "very unusual sound" that continued until the gear cycle was complete. He also noticed an amber gear warning light. The pilot leveled off at 7,500 feet and began to troubleshoot the problem by referencing the emergency procedures in the Pilot Operating Handbook (POH), which included two attempts to manually extend the gear. The pilot then checked the hydraulic fluid reservoir and it was empty. He then advised the tower of his situation and they suggested that he place a quart of engine oil in the hydraulic fluid reservoir and re-attempt a gear extension. The pilot added the oil and made another attempt to manually extend the landing gear, but to no avail. The pilot then flew by the control tower and tower personnel told him no gear was visible. The pilot said he then made a no-gear landing as directed by the POH on Runway 26R. According to the Pueblo Airport Operations Incident/Accident Report, the pilot landed with the nose gear down and locked and the main landing gear not down and locked. The airplane landed approximately 1,000 feet from the runway threshold. Upon touchdown, the nose gear remained extended and the main landing gear retracted. The airplane skidded on the belly and the tail before it came to rest approximately 400 feet east of taxiway A10. There was no fire. A Federal Aviation Administration (FAA) inspector performed an examination of the airplane and reported that the left horizontal stabilizer was substantially damaged. According to a representative of the repair facility that fixed the airplane, an o-ring in the nose gear actuator piston had failed. In addition, a seal in the emergency extension system had also failed. Once the failed o-ring and seal were replaced, the landing gear functioned normally. ## Aircraft - Registration: [N6850B](https://openairdocs.org/aircraft/N6850B), registered now, S/N 21062845 (OpenAirDocs) - Reported make and model: CESSNA T210M - Registry model: [Cessna T210M](https://openairdocs.org/model/cessna-t210m) (registry code 2073451) (OpenAirDocs) - Registry engine: [Continental TSIO-520 series](https://openairdocs.org/engine/continental-tsio-520-series) (registry code 17040, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 21062845 - Engines: CONT MOTOR TSIO-520 SER 300 horsepower reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Operator: Cuevas Orlando - Registered owner: Cuevas Orlando - Airworthiness certificate: Standard, Normal - Departed: PUB, Pueblo, CO - Destination: PUB, Pueblo, CO - Flight plan: Unknown - Airport: PUB, Pueblo, runway 26R, 10,498 × 150 ft, concrete ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 48; injuries: none; private; airplane ratings: single-engine land; instrument ratings: airplane; medical: class 3, with waivers/limitations; seat: left; flight hours: 1,101 total, 781 in this make and model ## Weather - Conditions: Visual (VMC), Day - Wind: 270° at 14 knots, gusting 21 - Visibility: 10 statute miles - Temperature: 66 °F, dew point 27 °F - Altimeter: 29.79 inHg - Observed at: PUB ## 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 20110521009329A](https://openairdocs.org/incident/20110521009329A), May 21, 2011: Cessna T210M, Pueblo, CO, Substantial damage. On may 21, 2011 at 1023 MDT a Cessna 210, N6850B, landed gear up at the pub. Visual meteorological conditions prevaled at the time. The aircraft received… ## Docket (4 files) The files NTSB released with the investigation on December 14, 2011, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=79233. 1.6 MB in all. - Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 503 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40359700&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Redacted.PDF - Written Statement-Pilot (item 2, .PDF, 171 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40359701&FileExtension=.PDF&FileName=Written%20Statement-Pilot-Redacted.PDF - Pueblo Airport Report (item 3, .PDF, 864 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40359704&FileExtension=.PDF&FileName=Pueblo%20Airport%20Report-Redacted.PDF - Record of Conversation- Beegles Aircraft (item 4, .PDF, 70 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40359851&FileExtension=.PDF&FileName=Record%20of%20Conversation-%20Beegles%20Aircraft-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.