# NTSB CEN11LA375: Boeing A75N1(PT17), N50052, Junction City, KS, June 4, 2011 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: June 4, 2011, 14:15 local (19:15 UTC) - Place: Junction City, KS - Coordinates: 39.043056, -96.843055 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=39.0431&lon=-96.8431&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: 2 uninjured - Status: Completed, report October 3, 2011 - Report: Approved by Office Director - NTSB office: Central Region - Parties: FAA FSDO - NTSB case key (mKey): 79311 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CEN11LA375 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/79311/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=79311 - Page: https://openairdocs.org/ntsb/CEN11LA375 ## Probable cause The degraded engine performance due to low compression on the cylinder and delayed ignition timing. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Ignition system](https://openairdocs.org/ntsb-findings/01057400): Aircraft › Aircraft power plant · Incorrect use/operation (probable cause); cases with it: [Boeing A75N1(PT17), 1 case](https://openairdocs.org/ntsb-findings/01057400/cases.md?model=1380134), [All aircraft, 18 cases](https://openairdocs.org/ntsb-findings/01057400/cases.md) - [Engine (reciprocating): recip eng cyl section](https://openairdocs.org/ntsb-findings/01058530): Aircraft › Aircraft power plant · Malfunction (probable cause); cases with it: [Boeing A75N1(PT17), 2 cases](https://openairdocs.org/ntsb-findings/01058530/cases.md?model=1380134), [All aircraft, 373 cases](https://openairdocs.org/ntsb-findings/01058530/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: [Boeing A75N1(PT17), 9 cases](https://openairdocs.org/ntsb-events/342/sequence.md?model=1380134), [All aircraft, 1,858 cases](https://openairdocs.org/ntsb-events/342/sequence.md) - [Emergency descent: Collision with terr/obj (non-CFIT) ](https://openairdocs.org/ntsb-events/470); cases with it: [Boeing A75N1(PT17), 22 cases](https://openairdocs.org/ntsb-events/470/sequence.md?model=1380134), [All aircraft, 10,189 cases](https://openairdocs.org/ntsb-events/470/sequence.md) ## Analysis According to the pilot, during the initial climb after takeoff, the engine started losing power. The pilot believed the airplane was too far down the runway to abort the takeoff, so he continued the climb. Shortly after, the airplane impacted a tree and a house resulting in substantial damage to both wings. A postaccident examination of the engine revealed that the No. 6 cylinder had measured compression of 34/80 and that the ignition timing on the forward and aft bank of spark plugs was delayed resulting in a degradation of engine power. The airplane was loaded to within 150 pounds of the airplane's gross weight, and calculations of relevant meteorological data revealed that the density altitude was 3,350 feet. ## Factual narrative On June 4, 2011, approximately 1415 central daylight time, a Boeing A75N1 (PT17) airplane, N50052, impacted a tree and a house near Freeman Field Airport (K3JC), Junction City, Kansas. The commercial pilot and passenger were not injured and the airplane was substantially damaged. The airplane was registered to and operated by the pilot under the provisions of 14 Code of Federal Regulations Part 91 as a personal flight. Visual meteorological conditions prevailed for the flight, which operated without a flight plan. The flight was originating at the time of the accident. The pilot reported that there was a loss of engine power shortly after departure. He was anticipating an rpm of 1,800 to 1,850; however, the tachometer indicated 1,700 rpm and the rpm was decreasing. The pilot altered his heading by 10 degrees to avoid higher obstacles; however, the airplane impacted a tree and a house before a forced landing site could be located. Both wings were crushed, bent, and broken during the impact sequence. The Federal Aviation Administration (FAA) inspector who attended the engine examination reported that the number six cylinder had a measured compression of 34/80 and that an air leak into the exhaust stack could be heard. In addition, the ignition timing on the forward bank of spark plugs was delayed by 2.5 degrees and the ignition timing on the rear bank of spark plugs was delayed by 5 degrees, resulting in a degradation of engine power. Further examination of the airframe confirmed control continuity to all flight controls. According to both the FAA and the pilot, the airplane was loaded to within 150 pounds of the airplane's gross take-off weight. Calculations of relevant meteorological data revealed that the density altitude was 3,350 feet. ## Aircraft - Registration: [N50052](https://openairdocs.org/deregistered/N50052-2018-05-30), registration cancelled 2018-05-30, S/N 75-1082, built 1941 (OpenAirDocs) - Reported make and model: BOEING A75N1(PT17) - Registry model: [Boeing A75N1(PT17)](https://openairdocs.org/model/boeing-a75n1-pt17) (registry code 1380134) (OpenAirDocs) - Registry engine: [Lycoming R680-4P-B4](https://openairdocs.org/engine/lycoming-r680-4p-b4) (registry code 41542, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 75-1082 - Airframe hours: 4508 - Engines: LYCOMING R680-4P-B4 225 horsepower reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Airworthiness certificate: Standard, Normal - Last inspection: Annual, May 1, 2011 - Departed: K3JC, Junction City, KS - Destination: K3JC, Junction City, KS ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 66; injuries: none; commercial; airplane ratings: multi-engine land, single-engine land; instrument ratings: airplane; medical: class 2, with waivers/limitations; last flight review April 10, 2010; seat: rear; flight hours: 8,300 total, 80 in this make and model, 8,100 as pilot in command, 27 in the last 90 days, 14 in the last 30 days, 0 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: variable at 4 knots - Visibility: 10 statute miles - Lowest ceiling: 19,000 ft broken - Temperature: 88 °F, dew point 70 °F - Altimeter: 30.06 inHg - Observed at: KFRI, 4 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 20110604011239A](https://openairdocs.org/incident/20110604011239A), Jun 4, 2011: Boeing A75N1(PT17), Junction City, KS, Substantial damage. At 14:13 CDT (local time) on June 4, 2011 the pilot of a Boeing A75N1, N50052 experienced a loss of power during climb after take-off from Junction City… ## Docket (1 files) The files NTSB released with the investigation on July 1, 2011, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=79311. 4.5 MB in all. - Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 4.5 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40349590&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-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.