# NTSB CEN14LA334: Piper PA-28-140, N9898W, Granbury, TX, July 2, 2014 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: July 2, 2014, 08:42 local (13:42 UTC) - Place: Granbury, TX - Coordinates: 32.436111, -97.813331 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=32.4361&lon=-97.8133&mi=10 - Phase of flight: [Takeoff](https://openairdocs.org/ntsb-phases/300) (OpenAirDocs' grouping) - Defining event: [Takeoff: Loss of engine power (partial)](https://openairdocs.org/ntsb-events/342) - Highest injury: No injuries - Injuries: 2 uninjured - Status: Completed, report January 14, 2015 - Report: Approved by Office Director - NTSB office: Central Region - Parties: FAA North Texas FSDO, Piper Aircraft - NTSB case key (mKey): 89589 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CEN14LA334 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/89589/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=89589 - Page: https://openairdocs.org/ntsb/CEN14LA334 ## Probable cause The partial loss of engine power due to the failure of the exhaust valve. ## 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: [Piper PA-28-140, 6 cases](https://openairdocs.org/ntsb-findings/01058530/cases.md?model=7102802), [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. - [Takeoff: Loss of engine power (partial)](https://openairdocs.org/ntsb-events/342) (defining event); cases with it: [Piper PA-28-140, 47 cases](https://openairdocs.org/ntsb-events/342/sequence.md?model=7102802), [All aircraft, 1,858 cases](https://openairdocs.org/ntsb-events/342/sequence.md) - [Takeoff: Collision with terr/obj (non-CFIT) ](https://openairdocs.org/ntsb-events/470); cases with it: [Piper PA-28-140, 137 cases](https://openairdocs.org/ntsb-events/470/sequence.md?model=7102802), [All aircraft, 10,189 cases](https://openairdocs.org/ntsb-events/470/sequence.md) ## Analysis The flight instructor reported that, after takeoff, when the airplane was about 500 ft above ground level, the engine started to run roughly and lose power. The engine rpm decreased to about 1,100 rpm as the flight instructor attempted to turn the airplane 180 degrees back toward the airport. However, he was unable to land at the airport, so he made a forced landing to a field short of the runway. During a postaccident engine test run, the engine initially ran roughly, and black smoke was observed coming from the exhaust. After a brief warmup, the engine could only produce about 1,600 rpm at full throttle, and the engine test run was stopped. The examination of the No. 3 cylinder revealed that the exhaust valve was broken in several pieces and that some fragments remained in the cylinder, which produced gouging and scraping to the piston and cylinder head. The broken exhaust valve, spring, exhaust valve keepers, and rotating cap exhibited carbon buildup. Examination revealed a wear pattern on the top of the No. 3 cylinder exhaust valve rotator cap consistent with rocker arm wear. No rotational signatures were observed along the edge of the cap near the heavy carbon buildup, indicating that the rotator cap had stopped rotating, which subsequently led to a hot spot on the exhaust valve and caused the valve to fail. ## Factual narrative On July 2, 2014, about 0842 central daylight time, a Piper PA-28-140, N9898W, sustained substantial damage during a forced landing after a loss of engine power during takeoff at the Granbury Regional Airport (GDJ), Granbury, Texas. The flight instructor and passenger were not injured. The airplane was registered to Thunderbolt Aviation LLC and operated by Iron Compass Aviation under the provisions of the 14 Code of Federal Regulations Part 91 as an instructional flight. Visual meteorological conditions prevailed at the time of the accident, and a visual flight rules flight plan was filed. The airplane was departing GDJ and was en route to the Waco Regional Airport (ACT), Waco, Texas. The flight instructor reported that the airplane was about 500 feet above ground level when the engine started to run rough along with a loss of engine power. The engine rpm decreased to about 1,100 rpm as the flight instructor attempted to complete a 180-degree turn back to the airport. However, he was unable to land on the airport, so he completed a forced landing to a field short of the runway. The airplane's right wing hit a tree during the landing roll, which resulted in substantial damage to the wing. The on-site examination of the airplane by Federal Aviation Administration inspectors revealed that there appeared to be no damage to the engine and no apparent reason for the loss of engine power. The airplane wreckage was transported to an aircraft storage facility for further examination and an engine run. An engine run was conducted using an external fuel supply. After priming the fuel system with the electric fuel pump, the engine was started. The engine sounded like it was running rough, and some black smoke could be seen from the exhaust. After a brief warm up, the engine would not operate more than about 1,600 rpm at full throttle. The engine run was stopped and a compression check was performed. The No. 3 cylinder did not have any compression. The examination of the No. 3 cylinder revealed that the exhaust valve was broken in several pieces and some fragments remained in the cylinder. The broken exhaust valve, spring, exhaust valve keepers, and rotator cap all exhibited carbon build-up. The piston and cylinder head exhibited gouging and scraping consistent with secondary damage from the fragments. The examination of the No. 3 cylinder exhaust valve rotator cap revealed that it had a wear pattern on the top of the cap that was consistent with rocker arm wear, and no rotational signatures along the edge of the cap where there was heavy carbon build-up. The engine was a 150-horsepower Lycoming O-320-E2A. The last annual maintenance inspection was conducted on June 2, 2014, with at total aircraft time of 3,464 hours. At the time of the accident, the engine had about 2,040 hours since the last overhaul. The airplane had flown about 46 hours since the annual/100-hour maintenance inspection. The recommended time between overhauls (TBO) is 2,000 hours, but it isnot a mandatory requirement under Part 91 regulations. ## Aircraft - Registration: [N9898W](https://openairdocs.org/deregistered/N9898W-2018-04-06), registration cancelled 2018-04-06, S/N 28-23418, built 1967 (OpenAirDocs) - Reported make and model: PIPER PA-28-140 - Registry model: [Piper PA-28-140](https://openairdocs.org/model/piper-pa-28-140) (registry code 7102802) (OpenAirDocs) - Registry engine: [Lycoming 0-320 series](https://openairdocs.org/engine/lycoming-0-320-series) (registry code 41508, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 28-23418 - Year built: 1967 - Airframe hours: 3464 - Engines: LYCOMING 0-320-E2A 150 horsepower reciprocating - Damage: Substantial damage - Flight: Instructional, Part 91 - Operator: Iron Compass Aviation - Registered owner: Thunderbolt Aviation LLC - Airworthiness certificate: Standard, Normal - Last inspection: Annual, June 2, 2014 - Departed: GDJ, Granbury, TX - Destination: ACT, Waco, TX - Flight plan: VFR - Airport: GDJ, Granbury Regional Airport, runway 14, 3,603 × 60 ft, asphalt - Equipment: Stall warning system ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 71; injuries: none; airline transport, flight instructor; airplane ratings: multi-engine land, single-engine land; instrument ratings: airplane; medical: class 3, with waivers/limitations; last flight review June 12, 2014; seat: right; flight hours: 10,341 total, 250 in this make and model, 111 in the last 90 days, 43 in the last 30 days - Student pilot; age 51; injuries: none; medical: class 3, with waivers/limitations; seat: left; flight hours: 43 total, 43 in this make and model ## Weather - Conditions: Visual (VMC), Day - Visibility: 10 statute miles - Temperature: 81 °F, dew point 70 °F - Altimeter: 30.06 inHg - Observed at: GDJ ## 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 20140702017849A](https://openairdocs.org/incident/20140702017849A), Jul 2, 2014: Piper PA-28-140, Granbury, TX, Substantial damage. N9898W departed rwy 14 Granbury regional airport (kgdj). On climb out at approximately 500 feet AGL the aircraft began to lose engine power. Student on the… ## Other investigations on N9898W (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 MKC77DCG09](https://openairdocs.org/ntsb/MKC77DCG09), Nov 24, 1976: Piper PA-28 (N9898W), Fayette, MO, substantial damage ## Docket (10 files) The files NTSB released with the investigation on November 6, 2014, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=89589. 18.0 MB in all. - NTSB Form 6120.1 (item 1, .PDF, 3.8 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40418685&FileExtension=.PDF&FileName=NTSB%20Form%206120.1-Redacted.PDF - Engine Logbook Excerpt (item 2, .PDF, 354 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40418686&FileExtension=.PDF&FileName=Engine%20Logbook%20Excerpt-Redacted.PDF - NTSB Party Form (item 3, .PDF, 473 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40418687&FileExtension=.PDF&FileName=NTSB%20Party%20Form-Redacted.PDF - Wreckage Release (item 4, .PDF, 222 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40418688&FileExtension=.PDF&FileName=Wreckage%20Release-Redacted.PDF - Photo 1 - View of airplane on trailer (item 5, .PDF, 2.1 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40418689&FileExtension=.PDF&FileName=Photo%201%20-%20View%20of%20airplane%20on%20trailer%0D%0A-Master.PDF - Photo 2 – View of damaged piston (item 6, .PDF, 3.2 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40418690&FileExtension=.PDF&FileName=Photo%202%20%E2%80%93%20View%20of%20damaged%20piston-Master.PDF - Photo 3 – View of cylinder damage (item 7, .PDF, 2.5 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40418691&FileExtension=.PDF&FileName=Photo%203%20%E2%80%93%20View%20of%20cylinder%20damage%0D%0A-Master.PDF - Photo 4 – Exhaust valve parts (item 8, .PDF, 2.5 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40418692&FileExtension=.PDF&FileName=Photo%204%20%E2%80%93%20Exhaust%20valve%20parts-Master.PDF - Photo 5 – View of exhaust valve rotator cap (item 9, .PDF, 2.8 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40418693&FileExtension=.PDF&FileName=Photo%205%20%E2%80%93%20View%20of%20exhaust%20valve%20rotator%20cap-Master.PDF - Video of engine run (item 10, .PDF, 15 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40418697&FileExtension=.PDF&FileName=Video%20of%20engine%20run-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.