# NTSB CEN13IA270: Piaggio P180, N139SL, Clearwater, FL, April 24, 2013 - Type: NTSB incident investigation - Classification: Incident · No injuries · Incident investigation · Final report - Date: April 24, 2013, 17:20 local (21:20 UTC) - Place: Clearwater, FL - Coordinates: 27.905, -82.687225 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=27.9050&lon=-82.6872&mi=10 - Phase of flight: [Landing](https://openairdocs.org/ntsb-phases/550) (OpenAirDocs' grouping) - Defining event: [Landing-landing roll: Sys/Comp malf/fail (non-power)](https://openairdocs.org/ntsb-events/330) - Highest injury: No injuries - Injuries: 6 uninjured - Status: Completed, report March 24, 2014 - Report: Approved by Office Director - NTSB office: Central Region - Parties: FAA - NTSB case key (mKey): 86858 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CEN13IA270 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/86858/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=86858 - Page: https://openairdocs.org/ntsb/CEN13IA270 ## Probable cause The failure of the nose landing gear steering manifold during landing, which resulted in an uncommanded and uncontrollable right turn, and the overhaul facility’s improper overhaul of the nose landing gear steering manifold. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Landing gear system: nose/tail landing gear](https://openairdocs.org/ntsb-findings/01023220): Aircraft › Aircraft systems · Malfunction (probable cause); cases with it: [Piaggio P180, 1 case](https://openairdocs.org/ntsb-findings/01023220/cases.md?model=6960204), [All aircraft, 185 cases](https://openairdocs.org/ntsb-findings/01023220/cases.md) - [Maintenance](https://openairdocs.org/ntsb-findings/02062000): Personnel issues › Task performance · Maintenance personnel (probable cause); cases with it: [Piaggio P180, 2 cases](https://openairdocs.org/ntsb-findings/02062000/cases.md?model=6960204), [All aircraft, 143 cases](https://openairdocs.org/ntsb-findings/02062000/cases.md) - [Knowledge: knowledge of procedures](https://openairdocs.org/ntsb-findings/02032010): Personnel issues › Experience/knowledge · Maintenance personnel (probable cause); cases with it: [Piaggio P180, 1 case](https://openairdocs.org/ntsb-findings/02032010/cases.md?model=6960204), [All aircraft, 41 cases](https://openairdocs.org/ntsb-findings/02032010/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: Runway excursion](https://openairdocs.org/ntsb-events/300); cases with it: [Piaggio P180, 3 cases](https://openairdocs.org/ntsb-events/300/sequence.md?model=6960204), [All aircraft, 3,643 cases](https://openairdocs.org/ntsb-events/300/sequence.md) - [Landing-landing roll: Sys/Comp malf/fail (non-power)](https://openairdocs.org/ntsb-events/330) (defining event); cases with it: [Piaggio P180, 1 case](https://openairdocs.org/ntsb-events/330/sequence.md?model=6960204), [All aircraft, 994 cases](https://openairdocs.org/ntsb-events/330/sequence.md) ## Analysis During landing, the nosewheel touched down, and the pilot heard the tire "squeal" and then felt the airplane gradually veer right. The pilot attempted to correct the turn by applying left rudder, left braking, and left-engine reverse thrust. The airplane came to a stop with the nose pointed more than 90 degrees right of the runway centerline. Examination of the nose landing gear steering manifold revealed that it had recently been overhauled but that the overhaul was not conducted in accordance with the manufacturer's component maintenance manual (CMM); the overhaul facility used unapproved alternative tooling because it did not have the required tooling to conduct the overhaul as specified in the CMM. The nose landing gear steering manifold exhibited internal damage consistent with metal tooling marks that resulted from the use of improper tooling during the overhaul and led to the failure of the nose landing gear steering manifold during landing. ## Factual narrative On April 24, 2013, about 1720 eastern daylight time, a Piaggio P180 airplane, N139SL, received minor damage during a runway excursion at the St. Petersburg-Clearwater International Airport (KPIE), Clearwater, Florida. The air transport pilot and 5 passengers were not injured. The airplane received minor damage to the nose landing gear and wheel. The airplane was registered to Anoil Co. and operated by Avantiar under the provisions of 14 Code of Federal Regulations Part 91 as a business flight. Visual meteorological conditions prevailed for the flight and no flight plan was filed. The local flight originated from KPIE about 1550. During landing, when the nose wheel touched down, the pilot heard the sound of a tire squeal and then felt the airplane gradually veer to the right. The pilot attempted to correct the turn by applying left rudder, left braking, and left engine reverse thrust. The airplane came to a stop with the nose pointed more than 90 degrees to the right of the runway centerline. Only the nose landing gear exited the runway. The operator examined the nose landing gear after the event and performed multiple tests in attempt to determine the cause of the malfunction. When the hydraulics were turned on and the electric steering turned off, the steering actuator actuated the wheels 50 degrees to the right. When the electric steering was turned on, the steering actuator actuated the wheels back to the center position or 0 degrees. The steering manifold, serial number M/DAG74/04; part number 114180003, was removed from the nose landing gear and retained for further examination. The nose landing gear and steering manifold were overhauled by Advantage Aviation Technologies II, LLC (AAT) on March 15, 2013. According to the AAT work order, the steering manifold was overhauled in accordance with Component Maintenance Manual (CMM) 32-50-50, Revision 6. A post incident examination was conducted on the steering manifold. The purpose of this examination was to reveal any mechanical malfunctions or failures of the component. It was also to discover and evaluate the overhaul procedures used by AAT. The testing procedures used by the group were the manufacturer's Component Maintenance Manuals (CMMs) which are the correct manuals to use when overhauling the landing gear and its components. The feedback and control readings were all completed on an analog scale as provided by AAT, not a digital scale as specified in the CMM. The Test Box DRT66770, as specified in the CMM, was not available during testing and was never used by AAT during the overhaul because they do not possess one. A 1985 era Dowty-Rotol Ltd. wiring diagram, 460006820 - sheet 2 of 5, was located at AAT and was used to engineer a replacement test box which was used in all tests performed by AAT and by the group. None of the other required tooling and test boxes, as specified by the CMM, were available at AAT. The steering manifold was first connected to an exemplar Piaggio P180 landinggear. With the system electrically de-energized and hydraulic pressure available the actuator steered left without any commands or inputs. The bias steering check was accomplished and the actuator always actuated to the left. The test was performed twice and the actuator arm moved 6 degrees the first time and about 14 degrees the second time. The tests did not replicate the uncommanded right turn as experienced during the runway excursion. The steering manifold was then connected to a hydraulic test rig and tested per CMM 32-50-50, Revision 8, which was the most current revision at the time of the examination. The group decided that the tests were invalid because ATT did not possess the specified test box. The manifold did not pass any of the other CMM functional tests because the solenoid valve inside the manifold would not close properly. The manifold was then disassembled and examined in order to reveal any anomalies inside the unit that would not allow normal operation. The examination revealed multiple scratches and damage noted to the armature plate and retainer ring. One wave washer and two shims, which measured 0.003 inches in thickness, were located inside the sleeve assembly. The wire connected to the electrical connector was damaged and had a white insulation sleeve placed over it, which ATT had installed during the overhaul. The installation of the insulation sleeve was not a specified procedure in the CMM. A review of the original overhaul paperwork revealed multiple discrepancies. ATT omitted procedures during the overhaul. AAT used alternative tooling which was not approved by the CMM and not referenced in the overhaul paperwork. AAT did not possess any written procedures to which they worked from to validate that the work was completed properly. The manifold was not able to be tested as required in the CMM, as the overhaul facility did not possess the required equipment and tooling and testing equipment. ## Aircraft - Registration: [N139SL](https://openairdocs.org/deregistered/N139SL-2018-08-09), registration cancelled 2018-08-09, S/N 1104, built 2005 (OpenAirDocs) - Reported make and model: PIAGGIO P180 - Registry model: [Piaggio P180](https://openairdocs.org/model/piaggio-p180) (registry code 6960204) (OpenAirDocs) - Registry engine: [Pratt & Whitney PT6A series](https://openairdocs.org/engine/pratt-whitney-pt6a-series) (registry code 52032, turbo-prop) (OpenAirDocs) - Category: Airplane - Serial number: 1104 - Airframe hours: 7989 - Engines: Pratt & Whitney PT6A-66 850 horsepower turbo prop; Pratt & Whitney PT6A-66 850 horsepower turbo prop - Damage: Minor damage - Flight: Business, Part 91 - Operator: Avantair Inc - Registered owner: Anoil Co - Airworthiness certificate: Standard, Normal - Last inspection: Continuous airworthiness, April 23, 2013, 2 hours before - Departed: KPIE, Clearwater, FL - Destination: KPIE, Clearwater, FL - Airport: KPIE, St Petersburg-Clearwater Inter, runway 36R, 9,730 × 150 ft, asphalt ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 48; injuries: none; airline transport, commercial; airplane ratings: multi-engine land, single-engine land; instrument ratings: airplane; medical: class 1, without waivers/limitations; last flight review January 30, 2013; seat: left; restraint: 3-point; flight hours: 6,553 total, 1,115 in this make and model, 9 in the last 90 days, 3 in the last 30 days, 3 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 320° at 10 knots - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 82 °F, dew point 61 °F - Altimeter: 30.09 inHg - Observed at: KPIE ## FAA reports on this event (1) The FAA's own accident and incident reports, matched to the aircraft by N-number and date (OpenAirDocs). - [Incident 20130424006479I](https://openairdocs.org/incident/20130424006479I), Apr 24, 2013: Piaggio P180, Clearwater, FL, No damage. Following a normal touch down for landing and subsequently lowering the nose wheel to the ground, the nose wheel was not centered, the aircraft turned right… ## Docket (6 files) The files NTSB released with the investigation on January 31, 2014, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=86858. 13.5 MB in all. - Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 271 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40394585&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Redacted.PDF - Evidence Control Form - Steering Manifold (item 2, .PDF, 184 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40394591&FileExtension=.PDF&FileName=Evidence%20Control%20Form%20-%20Steering%20Manifold-Redacted.PDF - Reports from Parties to the Investigation - Operator (item 3, .PDF, 123 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40394621&FileExtension=.PDF&FileName=Reports%20from%20Parties%20to%20the%20Investigation%20-%20Operator-Redacted.PDF - Maintenance Records - Repair Facility (item 4, .PDF, 57 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40394622&FileExtension=.PDF&FileName=Maintenance%20Records%20-%20Repair%20Facility-Redacted.PDF - Photograph 1: Steering Manifold Parts (item 5, .PDF, 6.5 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40397100&FileExtension=.PDF&FileName=Photograph%201%3A%20Steering%20Manifold%20Parts-Master.PDF - Photograph 2: Steering Manifold Part - Retainer Ring (item 6, .PDF, 6.4 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40397101&FileExtension=.PDF&FileName=Photograph%202%3A%20Steering%20Manifold%20Part%20-%20Retainer%20Ring-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.