# NTSB WPR11LA279: Rockwell International S-2R, N8520V, Brawley, CA, June 23, 2011 - Type: NTSB accident investigation - Classification: Accident · Serious injuries · Limited investigation · Final report - Date: June 23, 2011, 07:00 local (14:00 UTC) - Place: Brawley, CA - Coordinates: 33.020278, -115.51139 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=33.0203&lon=-115.5114&mi=10 - Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping) - Defining event: [Enroute-cruise: Loss of engine power (total)](https://openairdocs.org/ntsb-events/341) - Highest injury: Serious injuries - Injuries: 1 serious - Status: Completed, report August 7, 2012 - Report: Approved by Office Director - NTSB office: Western Pacific Region - Parties: Federal Aviation Administration FSDO - NTSB case key (mKey): 80862 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=WPR11LA279 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/80862/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=80862 - Page: https://openairdocs.org/ntsb/WPR11LA279 ## Probable cause The partial loss of engine power shortly after takeoff, which likely resulted from the failure of the piston connecting rod in cylinder number 3 due to hydraulic lock in that cylinder. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Engine (reciprocating): recip eng cyl section](https://openairdocs.org/ntsb-findings/01058530): Aircraft › Aircraft power plant · Failure (probable cause); cases with it: [Rockwell International S-2R, 2 cases](https://openairdocs.org/ntsb-findings/01058530/cases.md?model=7630202), [All aircraft, 373 cases](https://openairdocs.org/ntsb-findings/01058530/cases.md) - [Engine fuel and control](https://openairdocs.org/ntsb-findings/01057300): Aircraft › Aircraft power plant · Design (probable cause); cases with it: [Rockwell International S-2R, 1 case](https://openairdocs.org/ntsb-findings/01057300/cases.md?model=7630202), [All aircraft, 49 cases](https://openairdocs.org/ntsb-findings/01057300/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Enroute-cruise: Loss of engine power (total)](https://openairdocs.org/ntsb-events/341) (defining event); cases with it: [Rockwell International S-2R, 8 cases](https://openairdocs.org/ntsb-events/341/sequence.md?model=7630202), [All aircraft, 3,820 cases](https://openairdocs.org/ntsb-events/341/sequence.md) - [Landing-landing roll: Off-field or emergency landing](https://openairdocs.org/ntsb-events/440); cases with it: [Rockwell International S-2R, 8 cases](https://openairdocs.org/ntsb-events/440/sequence.md?model=7630202), [All aircraft, 3,365 cases](https://openairdocs.org/ntsb-events/440/sequence.md) - [Landing-landing roll: Collision with terr/obj (non-CFIT) ](https://openairdocs.org/ntsb-events/470); cases with it: [Rockwell International S-2R, 20 cases](https://openairdocs.org/ntsb-events/470/sequence.md?model=7630202), [All aircraft, 10,189 cases](https://openairdocs.org/ntsb-events/470/sequence.md) ## Analysis The pilot was en route to perform an aerial application pass when the airplane’s engine lost partial power. He made a forced landing in a nearby pasture; however, the airplane struck a railroad track during the landing roll, and a postcrash fire ensued. Examination of the radial engine revealed that the connecting rods for the pistons in cylinders 3 and 8 had failed, resulting in significant internal engine damage and the partial loss of power. Examination of the remains of the connecting rods for both cylinders revealed wear signatures that were mostly consistent with engine operation after failure. Because the engine continued operating after the failure, most features on the connecting rods fracture surfaces were obliterated, which made it difficult to identify the initial failure. However, further examination of the inside diameter surfaces of the wrist pin bearing of the number 3 cylinder connecting rod revealed wear signatures consistent with normal engine operation. Based on this finding, it is most likely that the event was initiated by the failure of the number 3 piston rod because it was not affected by the continued operation of the engine. The design of the engine's fuel priming system was such that cylinder number 3 was prone to piston hydraulic lock due to its low position within the priming system. Hydraulic lock is caused by excessive fuel being injected into a cylinder prior to engine start, and can be caused by either excessive priming, or a failure in the plunger or check valve assemblies, either of which could result in fuel trickling from the lowest nozzle within the system during non-operation. Postaccident fire damage precluded a thorough examination of the plunger and check valve assemblies. Hydraulic lock can result in a bent connecting rod and subsequent rod failure. The airplane was a low wing type, with integral wing fuel tanks located below the engine, and as such, it is unlikely that fuel had leaked into cylinder number 3 during non-operation. ## Factual narrative HISTORY OF FLIGHT On June 23, 2011, about 0700 Pacific daylight time (PDT), a Rockwell International S-2R, N8520V, struck a railroad track during a forced landing near Brawley, California. Farm Aviation, Inc., was operating the airplane under the provisions of Title 14 Code of Federal Regulations (CFR) Part 137 as an aerial application flight. The certificated commercial pilot sustained serious injuries. The airplane sustained substantial damage during the impact sequence, and was consumed by post crash fire. The flight departed Brawley Municipal Airport, Brawley, about 0630. Visual meteorological conditions prevailed, and no flight plan had been filed. The pilot reported that the airplane was loaded with powdered sulfur, and that while en route to the application area, he heard a bang, followed by a vibration and a total loss of engine power. He attempted to force land the airplane in a field, and during the landing roll, the airplane struck a railroad track. The collision breached the hopper, and the airplane came to rest intact about 60 feet beyond the initial impact point. The fixed-gear, tailwheel-equipped, low-wing airplane, serial number 2280R, was manufactured in 1976. The operator reported that at the time of the last annual inspection, dated June 11, 2011, the airplane had accrued a total time of 6,427 flight hours. The airplane was powered by a Pratt and Whitney R-1340-59 engine, serial number 11588, rated at 600 horsepower. The engine was a single-row, nine-cylinder, air-cooled radial type, with an integral centrifugal supercharger (blower). Maintenance logbooks indicated that Younkin Aviation, Inc., West Fork, Arkansas, overhauled the engine in May 2011, 21 flight hours prior to the accident. The records did not indicate the engines total time at overhaul. TESTS AND RESEARCH The engine was examined by the NTSB investigator-in-charge (IIC). The blower gearbox case had sustained impact damage, and had become separated from the aft section of the engine. All cylinder heads remained attached to the crankcase, all pushrods were straight, and the case was free of perforations or cracks. Removal of the rocker covers revealed the springs, valve stems, and rocker arms to be intact and wet with oil. The forward spark plugs were removed and examined. The electrodes were of the massive electrode type, and were dark grey in color, with wear signatures consistent with normal operation and a short service time when compared to the Champion Aviation check-a-plug chart AV-27. The crankshaft was seized, and could not be rotated. The engine was subsequently transported to the facilities of Younkin Aviation, Inc., for examination under the supervision of a Federal Aviation Administration (FAA) inspector. Disassembly revealed that the connecting rods for all cylinders except numbers 3 and 8 sustained bending damage, and remained attached to their respective pistons and the crankshaft/master rod assembly. The piston rod for cylinder 8 exhibited a slightcurve, remained attached to its piston, and had become separated from its link pin end, which was fragmented. Piston number 3 exhibited a slight curve, remained attached to its link pin, and had separated from its piston wrist pin, which was fragmented. Piston number 3 exhibited damage to its skirt consistent with piston rod contact. Fragmented sections of the cylinder number 3 and 8 connecting rods, link pins, bearings, and rod fragments were sent to the NTSB Office of Research and Engineering Materials Laboratory Division for examination. The fracture surfaces of the number 3 connecting rod, wrist pin end, and connecting bearings were battered such that the mode of fracture could not be determined. The piston end of the number 8 connecting rod was deformed and fractured through the I-beam and through the wrist pin bore. All fracture surfaces on the connecting rod were battered such that the mode of fracture could not be determined except for a small area, which exhibited features consistent with an overstress fracture. The inside diameter surfaces of the cylinder number 3 wrist pin bearings were free of grooves and scratches; all other recovered bearing and link pin contact surfaces exhibited deeply grooved wear scars consistent with low-stress abrasions. The complete examination report is contained within the public docket for this accident. ADDITIONAL INFORMATION The engine's fuel priming system consisted of a plunger, check valve, and distribution assembly, which supplied fuel to primer nozzles within the inlet ports of cylinders 1,2,3,8, and 9. The position of the nozzle for cylinder number 3 was at the lowest point in the priming system, with its intake manifold being the only one that flows in a downward direction to the intake valve. The Pratt and Whitney Maintenance manual applicable to the R1340 series engine states that excessive priming can cause fuel to drain to the lower cylinders, resulting in hydraulic lock and subsequent piston rod damage. Postaccident fire damage precluded an accurate assessment of the priming system prior to the accident. ## Aircraft - Registration: [N8520V](https://openairdocs.org/deregistered/N8520V-2017-07-18), registration cancelled 2017-07-18, S/N 2280R, built 1976 (OpenAirDocs) - Reported make and model: ROCKWELL INTERNATIONAL S-2R - Registry model: [Rockwell International S-2R](https://openairdocs.org/model/rockwell-international-s-2r) (registry code 7630202) (OpenAirDocs) - Registry engine: [Pratt & Whitney R1340 series](https://openairdocs.org/engine/pratt-whitney-r1340-series) (registry code 52016, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 2280R - Airframe hours: 6428 - Engines: Pratt and Whitney R1340 SERIES 600 horsepower reciprocating - Damage: Substantial damage - Fire: On-Ground - Flight: Aerial application, Part 137 - Operator: Farm Aviation Inc, doing business as Farm Aviation Inc - Registered owner: Farm Aviation Inc - Airworthiness certificate: Special, Restricted (Special) - Last inspection: Annual, June 11, 2011, 21 hours before - Departed: BWC, Brawley, CA - Destination: BWC, Brawley, CA - Airport: BWC, Brawley ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 63; injuries: serious; commercial; airplane ratings: multi-engine land, single-engine land; instrument ratings: airplane; medical: class 2, without waivers/limitations; last flight review November 1, 2009; seat: single; flight hours: 20,500 total, 2,000 in this make and model, 20,000 as pilot in command, 150 in the last 90 days, 40 in the last 30 days, 4 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 140° at 5 knots - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 79 °F, dew point 63 °F - Altimeter: 29.71 inHg - Observed at: KIPL, 10 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 20110623012599A](https://openairdocs.org/incident/20110623012599A), Jun 23, 2011: Rockwell International S-2R, Brawley, CA, Destroyed. N8520V an S2R during the repositioning for part 137 aerial application operation attempted an emergency landing due to engine issues, during the emergency… ## Other investigations on N8520V (1) 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. - [NTSB LAX04CA153](https://openairdocs.org/ntsb/LAX04CA153), Mar 11, 2004: Ayres S2R-600 (N8520V), Calipatria, CA, substantial damage. Probable cause: the failure of ground personnel to refuel the airplane with the proper fuel grade/octane, resulting in the airplane's loss of engine power. Also causal was the pilot's failure to detect the fuel… ## Docket (8 files) The files NTSB released with the investigation on June 12, 2012, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=80862. 12.0 MB in all. - Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 1.6 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40369967&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Redacted.PDF - Materials Laboratory Factual Report 12-055 (with 6 embedded images) (item 2, .PDF, 2.0 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40368831&FileExtension=.PDF&FileName=Materials%20Laboratory%20Factual%20Report%2012-055%20(with%206%20embedded%20images)-Master.PDF - Photo 1 - Airplane At Accident Site (item 3, .PDF, 1.4 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40369902&FileExtension=.PDF&FileName=Photo%201%20-%20Airplane%20At%20Accident%20Site-Master.PDF - Engine Maintenance Logbook (item 4, .PDF, 1.0 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40369968&FileExtension=.PDF&FileName=Engine%20Maintenance%20Logbook-Redacted.PDF - R-1340 Engine Maintenance Manual Excerpts (item 5, .PDF, 5.6 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40369904&FileExtension=.PDF&FileName=R-1340%20Engine%20Maintenance%20Manual%20Excerpts-Master.PDF - R-1340 Engine Maintenance Manual Excerpts-Primer System (item 6, .PDF, 32 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40369907&FileExtension=.PDF&FileName=R-1340%20Engine%20Maintenance%20Manual%20Excerpts-Primer%20System-Master.PDF - FAA Inspector Statement (item 7, .PDF, 166 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40369911&FileExtension=.PDF&FileName=FAA%20Inspector%20Statement-Master.PDF - Evidence Control Form (item 8, .PDF, 125 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40369936&FileExtension=.PDF&FileName=Evidence%20Control%20Form-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.