# NTSB CEN13LA437: Enstrom F-28A, N287Q, Danbury, TX, July 26, 2013 - Type: NTSB accident investigation - Classification: Accident · Serious injuries · Limited investigation · Final report - Date: July 26, 2013, 12:30 local (17:30 UTC) - Place: Danbury, TX - Coordinates: 29.244167, -95.345001 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=29.2442&lon=-95.3450&mi=10 - Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping) - Defining event: [Maneuvering: Flight control sys malf/fail](https://openairdocs.org/ntsb-events/333) - Highest injury: Serious injuries - Injuries: 1 serious, 1 minor - Status: Completed, report December 15, 2014 - Report: Approved by Office Director - NTSB office: Central Region - Parties: FAA, Enstrom Helicopter Corporation, NTSB - NTSB case key (mKey): 87587 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CEN13LA437 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/87587/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=87587 - Page: https://openairdocs.org/ntsb/CEN13LA437 ## Probable cause The loss of collective control for reasons that could not be determined due to extensive fire damage. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Main rotor system](https://openairdocs.org/ntsb-findings/01046200): Aircraft › Aircraft propeller/rotor · Malfunction (probable cause); cases with it: [Enstrom F-28A, 1 case](https://openairdocs.org/ntsb-findings/01046200/cases.md?model=3300406), [All aircraft, 25 cases](https://openairdocs.org/ntsb-findings/01046200/cases.md) - [Not determined](https://openairdocs.org/ntsb-findings/05000000): Not determined › Not determined · Unknown/Not determined (probable cause); cases with it: [Enstrom F-28A, 1 case](https://openairdocs.org/ntsb-findings/05000000/cases.md?model=3300406), [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. - [Maneuvering: Flight control sys malf/fail](https://openairdocs.org/ntsb-events/333) (defining event); cases with it: [Enstrom F-28A, 1 case](https://openairdocs.org/ntsb-events/333/sequence.md?model=3300406), [All aircraft, 410 cases](https://openairdocs.org/ntsb-events/333/sequence.md) - [Uncontrolled descent: Collision with terr/obj (non-CFIT) ](https://openairdocs.org/ntsb-events/470); cases with it: [Enstrom F-28A, 2 cases](https://openairdocs.org/ntsb-events/470/sequence.md?model=3300406), [All aircraft, 10,189 cases](https://openairdocs.org/ntsb-events/470/sequence.md) ## Analysis The flight instructor reported that, during takeoff, as the helicopter climbed through 300 feet, the private pilot started a right downwind turn. At that time, they heard a loud sound and ricocheting metal directly behind their heads, and the collective control was unresponsive. The flight instructor immediately took control of the helicopter and prepared to land. He lowered the collective to start a descent; however, the collective control was still unresponsive. He then chose to set the helicopter up for a long, shallow approach over an open field to the helipad. During a turn at 60 knots indicated airspeed, the helicopter began to oscillate vertically. The flight instructor heard popping sounds, and the oscillations increased. The main rotor rpm began to decrease, and the flight instructor lowered the collective and increased the throttle; however, the main rotor rpm continued to decrease. The helicopter started to shake violently, and the flight instructor observed that the blade pitch was very high. The shaking increased, and the flight instructor could no longer control the helicopter. A few seconds later, the helicopter impacted the ground. The collective walking beam was found fractured immediately forward of its pivot point. The aft end of the walking beam remained attached to the upper swashplate assembly, and the pivot point remained attached to the main transmission housing. The collective control linkages forward of the walking beam fracture were consumed by the postimpact fire. Examination of the fractured pieces from two brackets and the lower universal housing of the lower swashplate assembly, the end of the push-pull rod assembly, and the collective walking beam revealed features and deformation patterns on the fracture surfaces consistent with overstress separations. No indications of pre-existing cracks or fatigue cracks were observed. Darkened areas and/or rough surface texture consistent with heat damage were observed on all of the components' surfaces. The reason for the loss of collective control could not be determined due to extensive fire damage. ## Factual narrative On July 26, 2013, about 1230 central daylight time, an Enstrom F-28A helicopter, N287Q, was substantially damaged when it impacted the ground near Danbury, Texas. A postimpact fire ensued. The flight instructor was seriously injured and the private pilot had minor injuries. The helicopter was registered to and operated by Salaika Aviation LLC., under the provisions of 14 Code of Federal Regulations Part 91 as an instructional flight. Visual meteorological conditions prevailed for the flight, which operated without a flight plan. The flight was originating at the time of the accident.According to the written statement submitted by the flight instructor, he had flown with two other students prior to the accident flight. Those flights were uneventful and no mechanical anomalies were encountered. The flight instructor refueled the helicopter and confirmed that 25 gallons of fuel were on board. Immediately following the warm up and pre-takeoff checks, the private pilot hover taxied the helicopter to runway 24 and departed. As the helicopter was climbing through 200 feet, the private pilot initiated a turn to the crosswind. As the helicopter climbed through 300 feet, the private pilot started a right turn to the downwind, at which time a loud sound, described as a "gun shot", and ricocheting metal was heard by the instructor and private pilot. This sound was heard directly behind their heads and was accompanied by an unresponsive collective control. The flight instructor immediately took control of the helicopter and prepared to land immediately. He lowered the collective to start a descent; however, there was no response from the flight control input. The flight instructor elaborated that the collective "moved freely in [his] hand with no resistance or effect on the helicopter." He then elected to set the helicopter up for a long, shallow approach to the helipad, over an open field. During the turn at 60 knots indicated airspeed, the helicopter began to oscillate vertically. The flight instructor heard popping sounds, and the oscillations increased. The main rotor rpms began to decrease and the flight instructor lowered the collective and increased the throttle; however, this had no effect and the main rotor rpm continued to decrease. The helicopter started to shake violently and the flight instructor observed the blade pitch was very high. The shaking increased and the flight instructor could no longer control the helicopter. A few seconds later, the helicopter impacted the ground. The helicopter sustained substantial damage during the impact and the postimpact fire. Investigators with the National Transportation Safety Board (NTSB) examined the fractured and burnt remains of the collective push-pull rod assembly, cyclic, swashplate assembly, collective, and other related systems. The collective walking beam was found to have fractured immediately forward of its pivot point. The aft end of the walking beam remained attached to the upper swashplateassembly and the pivot point remained attached to the main transmission housing. The collective control linkages forward of the walking beam fracture were consumed by the post-impact fire. Fractured pieces from two brackets and the lower universal housing of the lower swashplate assembly, the end of the push-pull rod assembly, control cyclic, and collective pitch, and the collective walking beam were sent to the NTSB Material Laboratory for further examination. The examinations revealed features and deformation patterns on the fracture surfaces that were consistent with overstress separations. No indications of pre-existing cracks or fatigue cracks were observed. Darkened areas and/or rough surface texture consistent with heat damage were observed on the surfaces of all of the components. The collective walking beam was analyzed using a Thermo Scientific Niton XL3t-980 x-ray fluorescence (XRF) alloy analyzer. The alloy analyzer identified the material as ASTM A356 aluminum alloy, which is consistent with the alloy specified for the collective walking beam. ## Aircraft - Registration: [N287Q](https://openairdocs.org/deregistered/N287Q-2016-09-14), registration cancelled 2016-09-14, S/N 303, built 1975 (OpenAirDocs) - Reported make and model: ENSTROM F-28A - Registry model: [Enstrom F-28A](https://openairdocs.org/model/enstrom-f-28a) (registry code 3300406) (OpenAirDocs) - Registry engine: [Lycoming I0360 series](https://openairdocs.org/engine/lycoming-i0360-series) (registry code 41515, reciprocating) (OpenAirDocs) - Category: Helicopter - Serial number: 303 - Airframe hours: 7202 - Engines: LYCOMING HIO360C1A 205 horsepower reciprocating - Damage: Substantial damage - Fire: On-Ground - Flight: Instructional, Part 91 - Operator: Salaika Aviation LLC - Registered owner: Salaika Tim - Airworthiness certificate: Standard, Normal - Last inspection: 100 hour, May 21, 2013 - Departed: 07TA, Danbury, TX - Destination: 07TA, Danbury, TX - Airport: 07TA, Salaika Aviation Airport ## Flight crew As NTSB recorded them. NTSB leaves out names. - Flight instructor; age 31; injuries: serious; flight instructor, commercial; airplane ratings: single-engine land; medical: class 2, without waivers/limitations; last flight review December 10, 2012; seat: right; restraint: lap only; flight hours: 50 total, 50 in this make and model, 50 in the last 90 days, 20 in the last 30 days - Pilot; age 65; injuries: minor; private; airplane ratings: single-engine land; medical: class 3, without waivers/limitations; seat: left; restraint: lap only; flight hours: 0 total, 0 in this make and model ## Weather - Conditions: Visual (VMC), Day - Wind: 200° at 8 knots - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 90 °F, dew point 73 °F - Altimeter: 30.03 inHg - Observed at: KLBX ## 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 20130726019429A](https://openairdocs.org/incident/20130726019429A), Jul 26, 2013: Enstrom F-28A, Danbury, TX, Destroyed. On July 26, 2013 the houston flight standards district office (FSDO) was notified of a helicopter crash in Danbury, Texas. The aircraft was reported as N287Q,… ## Other investigations on N287Q (2) 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 FTW90LA099](https://openairdocs.org/ntsb/FTW90LA099), Apr 22, 1990: Enstrom F-28A (N287Q), Danbury, TX, substantial damage. Probable cause: PILOT IN COMMAND'S FAILURE TO SEE AND AVOID WIRES DURING THE FINAL STAGE OF AN APPROACH TO A CONFINED AREA. A CONTRIBUTING FACTOR TO THE ACCIDENT WAS THE PILOT'S DISREGARD OF THE OPERATOR'S… - [NTSB MIA77DKG47](https://openairdocs.org/ntsb/MIA77DKG47), Jun 19, 1977: Enstrom F28A (N287Q), Flovilla, GA, substantial damage ## Docket (5 files) The files NTSB released with the investigation on October 29, 2014, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=87587. 2.0 MB in all. - Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 - Pilot (item 1, .PDF, 734 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40401104&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1%20-%20Pilot-Redacted.PDF - Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 - Operator (item 2, .PDF, 895 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40401108&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1%20-%20Operator-Redacted.PDF - Statement of Party Representatives to NTSB Investigation (item 3, .PDF, 62 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40397727&FileExtension=.PDF&FileName=Statement%20of%20Party%20Representatives%20to%20NTSB%20Investigation-Redacted.PDF - Materials Laboratory Report (item 4, .PDF, 84 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40418299&FileExtension=.PDF&FileName=Materials%20Laboratory%20Report-Redacted.PDF - Release of Aircraft Wreckage, NTSB Form 6120.15 (item 5, .PDF, 204 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40418300&FileExtension=.PDF&FileName=Release%20of%20Aircraft%20Wreckage,%20NTSB%20Form%206120.15-Redacted.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.