# NTSB WPR11LA187: Zenith 701, N128CF, El Centro, CA, April 6, 2011 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: April 5, 2011, 17:00 local (Apr 6, 2011, 00:00 UTC) - Place: El Centro, CA - Coordinates: 32.788887, -115.529441 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=32.7889&lon=-115.5294&mi=10 - Phase of flight: [Landing](https://openairdocs.org/ntsb-phases/550) (OpenAirDocs' grouping) - Defining event: [Landing-landing roll: Nose over/nose down](https://openairdocs.org/ntsb-events/096) - Highest injury: No injuries - Injuries: 2 uninjured - Status: Completed, report March 20, 2012 - Report: Approved by Office Director - NTSB office: Western Pacific Region - Parties: FAA FSDO - NTSB case key (mKey): 78777 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=WPR11LA187 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/78777/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=78777 - Page: https://openairdocs.org/ntsb/WPR11LA187 ## Probable cause A partial loss of engine power during the initial climb after takeoff due to oil starvation because of the failure of the No. 2 oil pump drive coupling. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Engine (reciprocating): recip eng oil sys](https://openairdocs.org/ntsb-findings/01058550): Aircraft › Aircraft power plant · Failure (probable cause); cases with it: [Richards David Stanley III Z701, 1 case](https://openairdocs.org/ntsb-findings/01058550/cases.md?model=05901LZ), [All aircraft, 130 cases](https://openairdocs.org/ntsb-findings/01058550/cases.md) - [Fluids: oil](https://openairdocs.org/ntsb-findings/01071020): Aircraft › Fluids/misc hardware · Not specified (probable cause); cases with it: [Richards David Stanley III Z701, 1 case](https://openairdocs.org/ntsb-findings/01071020/cases.md?model=05901LZ), [All aircraft, 174 cases](https://openairdocs.org/ntsb-findings/01071020/cases.md) - [Terrain: wet/muddy terrain](https://openairdocs.org/ntsb-findings/03021035): Environmental issues › Physical environment · Contributed to outcome; cases with it: [Richards David Stanley III Z701, 1 case](https://openairdocs.org/ntsb-findings/03021035/cases.md?model=05901LZ), [All aircraft, 110 cases](https://openairdocs.org/ntsb-findings/03021035/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); cases with it: [Richards David Stanley III Z701, 1 case](https://openairdocs.org/ntsb-events/342/sequence.md?model=05901LZ), [All aircraft, 1,858 cases](https://openairdocs.org/ntsb-events/342/sequence.md) - [Emergency descent: Off-field or emergency landing](https://openairdocs.org/ntsb-events/440); cases with it: [Richards David Stanley III Z701, 1 case](https://openairdocs.org/ntsb-events/440/sequence.md?model=05901LZ), [All aircraft, 3,365 cases](https://openairdocs.org/ntsb-events/440/sequence.md) - [Landing-landing roll: Nose over/nose down](https://openairdocs.org/ntsb-events/096) (defining event); cases with it: [Richards David Stanley III Z701, 1 case](https://openairdocs.org/ntsb-events/096/sequence.md?model=05901LZ), [All aircraft, 2,287 cases](https://openairdocs.org/ntsb-events/096/sequence.md) ## Analysis The pilot reported that, during the initial climb after takeoff, the airplane sustained a partial loss of engine power and that he initiated a forced landing to a wet, muddy, wheat field. During the landing roll, the nosewheel of the airplane dug into the soft terrain and the airplane nosed over. A postaccident examination of the engine revealed that the No. 2 cylinder and piston exhibited signatures consistent with oil starvation. During disassembly of the engine oil pump system, the No. 1 shaft/bearing assembly for the oil pump system was intact and operational. The No. 2 drive coupling was found damaged, out of alignment, and not functioning. This condition would result in the oil supply system supplying oil at a sporadic rate, below minimal volume and pressure, which would result in oil starvation primarily to the No. 2 cylinder assembly. ## Factual narrative On April 5, 2011, about 1700 Pacific daylight time, an amateur built experimental Zenith 701, N128CF, sustained substantial damage during a forced landing following a partial loss of engine power during takeoff initial climb from a private airstrip near El Centro, California. The private pilot was not injured, and his passenger sustained minor injuries. The airplane was registered to and operated by the pilot under the provisions of Title 14 Code of Federal Regulations Part 91. Visual meteorological conditions prevailed, and no flight plan was filed for the personal flight. The local flight was originating at the time of the accident. The pilot reported to the National Transportation Safety Board (NTSB) investigator-in-charge (IIC) that during takeoff initial climb to the south, he noticed a partial loss of engine power. The pilot initiated a forced landing to a wet, muddy, wheat field adjacent to his position. During the landing roll, the nose wheel of the airplane submerged within the soft terrain, and the airplane nosed over, which resulted in substantial damage to the vertical stabilizer and left wing root. Examination of the recovered engine by the pilot and a Federal Aviation Administration (FAA) inspector on June 17, 2011, revealed that when the exhaust stack for the number two cylinder was removed, visible damage to the number two cylinder wall and piston was observed. The engine was subsequently removed by the pilot and shipped to Recreational Power Engineering, Tiffin, Ohio, for further inspection. Examination of the three-cylinder Hirth 3701 engine, serial number 898687, by a representative of Recreational Power Engineering under the supervision of a Federal Aviation Administration (FAA) inspector was conducted on October 24, 2011. The inspection revealed that the number two piston exhibited signatures consistent with overheating. The number two piston pin and underside of the piston head were blue in color. The number two cylinder piston rings were seized within their respective ring lands and were worn smooth with the side of the piston, consistent with oil starvation to that cylinder. During disassembly of the engine oil pump system, the number one shaft/bearing assembly for the oil pump system was intact and operational. The number two drive coupling was found damaged, out of alignment, and not functioning. The representative from Recreational Power Engineering stated that the number two oil pump drive coupling would result in the oil supply system partially functioning and that the oil pump system would only supply oil at a sporadic rate below minimal volume and pressure, which would result in oil starvation primarily to the number two cylinder assembly. There was no evidence of a failure of the number two oil supply tube from the pump to the cylinder. The reason for the failure of the number two oil pump drive coupling was not determined. No aircraft maintenance records were located during the investigation. The pilot reportedthat at the time of the accident, the airplane had 44 hours total time on the engine and airframe. ## Aircraft - Registration: [N128CF](https://openairdocs.org/aircraft/N128CF), registered now, S/N 75203 (OpenAirDocs) - Reported make and model: ZENITH 701 - Registry model: [Richards David Stanley III Z701](https://openairdocs.org/model/richards-david-stanley-iii-z701) (registry code 05901LZ) (OpenAirDocs) - Registry engine: [Hirth 3701](https://openairdocs.org/engine/hirth-3701) (registry code 33702, 2 cycle) (OpenAirDocs) - Category: Airplane, amateur-built - Serial number: 75203 - Engines: Hirth 3701 100 horsepower reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Operator: Richards David Stanley III - Registered owner: Richards David Stanley III - Airworthiness certificate: Special, Experimental (Special) - Departed: El Centro, CA - Destination: El Centro, CA ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 41; injuries: none; private; airplane ratings: single-engine land; medical: class 3, without waivers/limitations; seat: left; flight hours: 1,400 total, 1,360 as pilot in command, 20 in the last 90 days, 10 in the last 30 days, 1 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 120° at 7 knots - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 88 °F, dew point 30 °F - Altimeter: 29.75 inHg - Observed at: KIPL, 6 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 20110406010149A](https://openairdocs.org/incident/20110406010149A), Apr 6, 2011: Richards David Stanley III Z701, El Centro, CA, Substantial damage. N128CF zenith 701 lost partial power after takeoff from ipl, pilot made an emergency landing in a muddy wheat field nosed over and came to rest inverted. ## Docket (4 files) The files NTSB released with the investigation on February 3, 2012, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=78777. 1.0 MB in all. - Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 568 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40361812&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Redacted.PDF - Record of Conversation - Pilot (item 2, .PDF, 52 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40361813&FileExtension=.PDF&FileName=Record%20of%20Conversation%20-%20Pilot-Master.PDF - FAA Engine Examination Correspondence (item 3, .PDF, 20 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40361815&FileExtension=.PDF&FileName=FAA%20Engine%20Examination%20Correspondence-Redacted.PDF - FAA Engine Examination (item 4, .PDF, 401 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40362170&FileExtension=.PDF&FileName=FAA%20Engine%20Examination-Redacted.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.