# NTSB ERA16LA094: Robinson Helicopter R22, N404LE, Lindenhurst, NY, January 27, 2016 - Type: NTSB accident investigation - Classification: Accident · No injuries · Class 3 · Limited · Final report - Date: January 27, 2016, 11:57 local (16:57 UTC) - Place: Lindenhurst, NY - Coordinates: 40.67139, -73.379165 - Nearby events: https://openairdocs.org/map.md?lat=40.6714&lon=-73.3792&mi=10 - Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping) - Defining event: [Enroute-cruise: Powerplant sys/comp malf/fail](https://openairdocs.org/ntsb-events/340) - Highest injury: No injuries - Injuries: 2 uninjured - Status: Completed - Report: Approved by Office Director - Investigation class: Class 3 - NTSB office: Eastern Region Aviation - Parties: Continental Motors, Lycoming Engines, FAA/FSDO - NTSB case key (mKey): 92643 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=ERA16LA094 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/92643/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=92643 - Page: https://openairdocs.org/ntsb/ERA16LA094 ## Probable cause A rough running engine as a result of an intermittent failure of the left magneto for reasons that could not be determined, which resulted in a subsequent autorotation, impact with a sign, and rollover. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Ignition system: magneto/distributor](https://openairdocs.org/ntsb-findings/01057414): Aircraft › Aircraft power plant · Failure (probable cause); cases with it: [All aircraft, 101 cases](https://openairdocs.org/ntsb-findings/01057414/cases.md) - [Not determined](https://openairdocs.org/ntsb-findings/05000000): Not determined › Not determined · Unknown/Not determined (probable cause); cases with it: [All aircraft, 2,247 cases](https://openairdocs.org/ntsb-findings/05000000/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Enroute-cruise: Powerplant sys/comp malf/fail](https://openairdocs.org/ntsb-events/340) (defining event); cases with it: [All aircraft, 820 cases](https://openairdocs.org/ntsb-events/340/sequence.md) - [Enroute-cruise: Loss of engine power (partial)](https://openairdocs.org/ntsb-events/342); cases with it: [All aircraft, 1,858 cases](https://openairdocs.org/ntsb-events/342/sequence.md) - [Autorotation: Off-field or emergency landing](https://openairdocs.org/ntsb-events/440); cases with it: [All aircraft, 3,365 cases](https://openairdocs.org/ntsb-events/440/sequence.md) ## Analysis According to the flight instructor, the helicopter had been airborne for about 2 hours when it began to experience vibrations, which increased in intensity. He stated that the vibrations became “very violent” as he began to reduce engine power and were soon followed by the activation of the low rotor rpm horn and light warning system. The flight instructor performed an autorotation to a street in a residential area. The helicopter touched down and bounced, the main rotor blades struck a sign, and the helicopter rolled over onto its right side, which resulted in substantial damage to the airframe. A postaccident engine test run revealed that after the engine was started, it operated smoothly at idle and when the rpm was increased; however, when the left magneto was selected, the engine shut down. Both magnetos were removed and functionally checked on a test stand with no malfunctions noted. Subsequent disassembly of the left magneto revealed that the internal magneto timing was off by two teeth, which would have increased the gap between the distributor gear finger and the distributor block’s stationary electrodes; but not precluded the magneto’s ability to function. The flight instructor was using full carburetor heat throughout the accident flight. It is likely that the cumulative effect of carburetor heat, which would have reduced engine rpm, and an intermittent failure of the left magneto for reasons that could not be determined resulted in the engine roughness that preceded the autorotation. ## Factual narrative On January 27, 2016, about 1157 eastern standard time, a Robinson R22 Beta, N404LE, was substantially damaged when it was involved in an accident near Lindenhurst, New York. The flight instructor and student pilot were not injured. The helicopter was operated as a Title 14 Code of Federal Regulations Part 91 instructional flight. According to the flight instructor, the helicopter had been airborne for about 2 hours and was returning to Republic Airport (FRG), Farmingdale, New York, when it began to experience vibrations, which increased in intensity. He further stated that, as he began to reduce power, the vibrations became “very violent” and were soon followed by the low rotor rpm horn and light warning system. The flight instructor performed an autorotation to a street in a residential neighborhood. The helicopter touched down and bounced, the main rotor blades struck a sign, and the helicopter rolled over onto its right side. The flight instructor stated that he was using full carburetor heat throughout the entire flight. On-site examination of the helicopter by a Federal Aviation Administration (FAA) inspector revealed that the tailboom separated just before the vertical fin, and the tail rotor gear box and tail rotor blades displayed damage consistent with ground contact. An unquantified amount of fuel was observed in the helicopter’s fuel tanks. The carburetor heat control was observed in the “ON” position. A subsequent engine test run revealed that after the engine was started, it operated smoothly at idle and when the rpm was increased; however, during a magneto check, when the left magneto was selected, the engine shut down. The engine continued to operate if the right or both magneto position was selected. Further examination of the left and right magnetos revealed that, when placed on a test stand, each respective magneto’s terminals produced a blue spark across a 7-millimeter gap throughout all magneto rpms. The torque putty on the left magneto’s case half mating screw was compromised. Subsequent disassembly of the left magneto revealed that the internal magneto timing was off by two teeth, which would have increased the gap between the distributor gear finger and the distributor block’s stationary electrodes. ## Aircraft - Registration: N404LE (not matched to a registry record) - Reported make and model: ROBINSON HELICOPTER R22 (Beta) - Category: Helicopter - Serial number: 4040 - Year built: 2006 - Airframe hours: 4669 - Engines: LYCOMING O-360-J2A 145 horsepower reciprocating - Damage: Substantial damage - Flight: Instructional, Part 91 - Operator: Academy of Aviation, LLC - Registered owner: November Alpha LLC - Airworthiness certificate: Standard, Normal - Last inspection: 100 hour, October 24, 2015, 92 hours before - Departed: FRG, Farmingdale, NY - Destination: FRG, Farmingdale, NY - Airport: FRG, Republic - Equipment: Unknown ## Flight crew As NTSB recorded them. NTSB leaves out names. - Flight instructor; age 26; injuries: none; flight instructor, commercial; instrument ratings: helicopter; medical: class 2, without waivers/limitations; last flight review July 30, 2015; seat: right; flight hours: 1,080 total, 600 in this make and model, 1,020 as pilot in command, 350 in the last 90 days, 100 in the last 30 days, 2 in the last 24 hours - Student pilot; age 27; injuries: none; seat: left ## Weather - Conditions: Visual (VMC), Day - Wind: 290° at 11 knots, gusting 19 - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 43 °F, dew point 21 °F - Altimeter: 30.04 inHg - Icing: Unknown - Turbulence: Unknown - Observed at: FRG, 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 20160127013559A](https://openairdocs.org/incident/20160127013559A), Jan 27, 2016: Robinson Helicopter R22 BETA, Lindenhurst, NY, Substantial damage. On Wednesday January 27, 2016 at approximately 1145 local hours a Robinson Helicopter registration number N404LE had a forced landing in the town of… ## Docket (7 files) The files NTSB released with the investigation on December 8, 2020, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=92643. 2.3 MB in all. - Pilot/operator aircraft accident report, NTSB form 6120.1 (item 1, PDF, 9 pages, 456 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=11548866&FileExtension=pdf&FileName=1_PO_RPT_FORM_Redacted-Rel.pdf - FAA inspectors statement (item 2, PDF, 1 page, 115 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=11550282&FileExtension=pdf&FileName=1a_FAA_Inspectors%20Statement_Redacted-Rel.pdf - FAA inspector statement - engine examination and test run (item 3, PDF, 2 pages, 83 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=11549820&FileExtension=pdf&FileName=2_FAA%20Engine%20Run%20Report-Rel.pdf - NTSB memorandum - magneto examination (item 4, PDF, 1 page, 131 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=11550300&FileExtension=pdf&FileName=2a_Memorandum%20Magento%20Exam-Rel.pdf - Maintenance records (excerpts) (item 5, PDF, 8 pages, 614 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=11550332&FileExtension=pdf&FileName=5_Maintenance_Records_Redacted-Rel.pdf - Statement of party representatives to NTSB investigation (item 6, PDF, 15 pages, 223 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=11549686&FileExtension=pdf&FileName=4_NTSB%20Party%20Statements_Redacted-Rel.pdf - Investigation photographs (item 7, PDF, 4 pages, 4 photos, 655 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=11550096&FileExtension=pdf&FileName=8_Investigation%20Photos-Rel.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.