# NTSB ERA10LA237: Piper PA 46-350P, N779MA, Parkersburg, WV, April 16, 2010 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: April 16, 2010, 15:20 local (19:20 UTC) - Place: Parkersburg, WV - Coordinates: 39.345275, -81.439163 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=39.3453&lon=-81.4392&mi=10 - Phase of flight: [Landing](https://openairdocs.org/ntsb-phases/550) (OpenAirDocs' grouping) - Defining event: [Landing-landing roll: Landing gear collapse](https://openairdocs.org/ntsb-events/094) - Highest injury: No injuries - Injuries: 2 uninjured - Status: Completed, report June 27, 2011 - Report: Approved by Office Director - NTSB office: Eastern Region Aviation - Parties: FAA/FSDO - NTSB case key (mKey): 75791 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=ERA10LA237 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/75791/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=75791 - Page: https://openairdocs.org/ntsb/ERA10LA237 ## Probable cause The inadequate design of the engine mount by the manufacturer, resulting in collapse of the nose landing gear. Contributing to the accident was the failure of the operator to adhere to the manufacturer's suggested engine mount inspection schedule. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Design: equipment design](https://openairdocs.org/ntsb-findings/04011010): Organizational issues › Development · Manufacturer (probable cause); cases with it: [All aircraft, 35 cases](https://openairdocs.org/ntsb-findings/04011010/cases.md) - [Landing gear system: nose/tail landing gear](https://openairdocs.org/ntsb-findings/01023220): Aircraft › Aircraft systems · Fatigue/wear/corrosion (probable cause); cases with it: [All aircraft, 185 cases](https://openairdocs.org/ntsb-findings/01023220/cases.md) - [Landing gear system: nose/tail landing gear](https://openairdocs.org/ntsb-findings/01023220): Aircraft › Aircraft systems · Failure (probable cause); cases with it: [All aircraft, 185 cases](https://openairdocs.org/ntsb-findings/01023220/cases.md) - [Inspection: scheduled/routine inspection](https://openairdocs.org/ntsb-findings/02061520): Personnel issues › Task performance · Pilot (probable cause); cases with it: [All aircraft, 167 cases](https://openairdocs.org/ntsb-findings/02061520/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Landing-landing roll: Landing gear collapse](https://openairdocs.org/ntsb-events/094) (defining event); cases with it: [All aircraft, 1,787 cases](https://openairdocs.org/ntsb-events/094/sequence.md) - [Landing-landing roll: Runway excursion](https://openairdocs.org/ntsb-events/300); cases with it: [All aircraft, 3,643 cases](https://openairdocs.org/ntsb-events/300/sequence.md) ## Analysis During landing, the airplane veered hard to the right when the nose gear was lowered to the runway after touchdown. The pilot attempted to maintain directional control with rudder input, but the airplane veered to the right and departed the runway. Initial examination of the airplane at the site revealed that the nose landing gear had collapsed and the attachment components between the nose landing gear actuator and the engine mount were fractured. Each of the right and left two-piece attachment feet were fractured at the nose landing gear actuator attach location. Detailed examination of the right foot showed evidence of fatigue, which covered a 0.75-inch arc and approximately 0.04 inches of the 0.06-inch wall thickness of the foot. The left foot also showed evidence of fatigue, which covered a 0.35-inch arc and was approximately 0.03 inches deep. The manufacturer had issued a series of Service Bulletins (SB 1103, with subsequent revisions A, B, and C) for PA-46-350P models that required inspections for cracks in the engine mounts in the areas of the nose landing gear actuator attachment feet. Inspections were to take place at the next regularly scheduled maintenance event, and at each 100 hours time in service or annual inspection, whichever occurred first. Records showed that SB 1103B was accomplished on the accident airplane during an annual inspection in 2007, but records of subsequent annual inspections in 2008 and 2009 showed that SB1103 was not accomplished. Previous nose gear failures and runway excursions resulted in the redesign of the original engine mount due to compliance (flexibility) in the engine mount actuator attach feet structure. This compliance issue was sometimes exasperated at various speeds, resulting in a high speed shimmy effect and subsequent uncommanded left or right turn of the nose wheel during takeoff and/or landing. The new engine mount incorporates a one piece design at the actuator attach point, eliminating the two piece feet design. The one piece design provides a less compliant structure, which prevents relative motion between the two feet in the original engine mount design. The Federal Aviation Administration did not mandate the actions outlined in SB 1103B, but compliance could have alerted the operator of any problems because the SB inspection criteria called for examinations of the engine mount in the areas where the fatigue cracks were located. Replacement of the engine mount with the new design that had one-piece nose landing gear actuator attachment feet would have relieved the operator of the manufacturer's repetitive inspection requirement, but because the accident airplane still had the welded two-piece attachment feet it was subject to the repetitive inspection per the service bulletin. ## Factual narrative On April 16, 2010, about 1520 eastern daylight time, a Piper PA 46-350P, N779MA, was substantially damaged when the nose landing gear collapsed upon landing at Parkersburg, West Virginia (PKB). The airplane was operated by P & C Aviation LLC. The commercial pilot and one passenger were not injured. Visual meteorological conditions prevailed, and an instrument flight rules (IFR) flight plan was filed for the business flight conducted under the provisions of 14 Code of Federal Regulations Part 91. The pilot reported that he was landing on runway 21 at PKB. The main landing gear touched down normally and as the nose gear was lowered to the runway, the airplane veered hard to the right. The pilot attempted to maintain directional control with full left rudder, but as the airplane slowed and rudder authority became less effective, the airplane departed the right side of the runway into the grass. An inspector from the Federal Aviation Administration (FAA) responded to the accident site and examined the wreckage. The structure surrounding the nose gear and engine mount was substantially damaged. A cursory examination of the nose gear revealed that the attachment components between the nose landing gear actuator and the engine mount were fractured. Photographs were taken of the affected components and the airplane was moved to a hangar and secured. The engine mount was subsequently disassembled and the fractured sections were removed and sent to the NTSB Materials Laboratory for examination and analysis. NTSB Materials Laboratory Examination / Findings: The engine mount was of a welded tubular construction, and the attachment feet were positioned at the aft end of the engine mount. Each attachment foot was constructed by welding a tube to a disk. The welded attachment feet on the airplane were of an older design (Newer attachment feet have since been redesigned to be machined from a single solid piece.). Each attachment foot was welded to three support tubes that extended forward and down and were welded to the engine mount. The right attachment foot was completely separated from the support tubes by fractures. The left attachment foot was separated from two of the support tubes by fractures, and one of the tubes supporting the left attachment foot was bent. Along the inner edge of the right attachment foot where the foot was welded to its center support tube, the fracture surface was smooth and retained curving crack arrest markings consistent with fatigue cracking emanating from multiple origins along the toe of the weld joining the foot and the support tube. The fatigue cracking propagated primarily through the parent metal of the attachment foot. The fatigue cracking extended over an arc length of approximately 0.75 inch, and penetrated at least 0.04 inch through the estimated 0.06-inch wall thickness of the foot. There was significant oxidation of the fracture surface in the area of fatigue cracking on the right attachment foot. No weldingdeficiencies (such as incomplete penetration or incomplete fusion) were observed in the welds joining the right attachment foot to the support tubes. Along the lower inner edge of the left attachment foot where the foot was welded to its center support tube, the fracture surface retained several regions that were smooth and had curving crack arrest markings consistent with fatigue cracking emanating from multiple origins along the weld joining the foot and the support tube. The fatigue cracking propagated through the parent metal of the center support tube and in the weld metal between the center and bottom support tubes. The area of fatigue cracking extended over a length of approximately 0.35 inch, and penetrated a maximum of approximately 0.03 inch deep. There was very little oxidation of the fracture surfaces in the area of fatigue cracking on the left attachment foot. No welding deficiencies (such as incomplete penetration or incomplete fusion) were observed in the welds joining the left attachment foot to the support tubes. A factual report (Materials Laboratory Factual Report No. 10-102) describing the detailed examination of the engine mount components is available in the public docket of supporting documentation for this accident investigation. Service Bulletin / Engine Mount Design Information: Beginning in April 2002, Piper issued a series of mandatory Service Bulletins (SB 1103, with subsequent revisions A, B and C) for PA-46-350P models, requiring inspections for cracks in the engine mounts in the areas of the nose landing gear actuator attachment feet. Inspections were to take place at the next regularly scheduled maintenance event, and at each 100 hours time in service or annual inspection, whichever occurred first. Replacement of the engine mount with the new design that had one-piece nose landing gear actuator attachment feet would have relieved the repetitive inspection requirement, but since the accident airplane still had the welded two-piece attachment feet, it was subject to repetitive inspection per the service bulletins. Maintenance Information: An examination of the airplane maintenance logbooks revealed that Piper SB 1103B was accomplished during an annual inspection on May 4, 2007. An examination of the logbook entries for the subsequent annual inspections accomplished on May 1, 2008 and June 5, 2009 revealed that Piper SB1103 was not accomplished. The operator did not provide a reason for why the inspections were not accomplished after May 4, 2007. ## Aircraft - Registration: N779MA (not matched to a registry record) - Reported make and model: PIPER PA 46-350P - Category: Airplane - Serial number: 4636279 - Airframe hours: 1670 - Engines: LYCOMING TIO 540 SER 350 horsepower reciprocating - Damage: Substantial damage - Flight: Business, Part 91 - Operator: P & C Aviation LLC - Registered owner: P & C Aviation LLC - Airworthiness certificate: Standard, Normal - Last inspection: Annual, June 8, 2009, 124 hours before - Departed: CLT, Charlotte, NC - Destination: PKB, Parkersburg, WV - Flight plan: IFR - Airport: PKB, Mid-Ohio Valley Regional, runway 21, 6,781 × 150 ft, asphalt ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 52; injuries: none; commercial; airplane ratings: single-engine land, multi-engine land; instrument ratings: airplane; medical: class 2, with waivers/limitations; last flight review July 23, 2009; seat: left; flight hours: 1,450 total, 281 in this make and model, 1,263 as pilot in command, 59 in the last 90 days, 25 in the last 30 days, 5 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 270° at 14 knots, gusting 30 - Visibility: 6 statute miles - Lowest ceiling: 6,000 ft broken - Temperature: 68 °F, dew point 55 °F - Altimeter: 29.94 inHg - Observed at: PKB ## 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 20100416032519A](https://openairdocs.org/incident/20100416032519A), Apr 16, 2010: Piper PA 46-350P, Parkersburg, WV, Substantial damage. During the touchdown phase of landing, the main landing gear touchdown was normal; but, during the nose landing gear touchdown, the aircraft veered hard right… ## Docket (5 files) The files NTSB released with the investigation on April 15, 2011, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=75791. 6.9 MB in all. - Materials laboratory Factual Report 10-102, Nose landing gear actuator attachments (item 1, .PDF, 510 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40339510&FileExtension=.PDF&FileName=Materials%20laboratory%20Factual%20Report%2010-102,%20Nose%20landing%20gear%20actuator%20attachments-Master.PDF - Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 2, .PDF, 798 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40339646&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Redacted.PDF - Excerpts from Airframe and Engine Logbooks (item 3, .PDF, 3.3 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40339669&FileExtension=.PDF&FileName=Excerpts%20from%20Airframe%20and%20Engine%20Logbooks-Redacted.PDF - Photo 1: Tire Marks on Runway Leading to Main Wreckage (FAA Digital Photo) (item 4, .PDF, 1.4 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40339670&FileExtension=.PDF&FileName=Photo%201%3A%20Tire%20Marks%20on%20Runway%20Leading%20to%20Main%20Wreckage%20(FAA%20Digital%20Photo)-Master.PDF - Photo 2: Main Wreckage, View from Right, Showing Collapsed Nose Gear (item 5, .PDF, 956 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40339671&FileExtension=.PDF&FileName=Photo%202%3A%20Main%20Wreckage,%20View%20from%20Right,%20Showing%20Collapsed%20Nose%20Gear-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.