Wednesday, May 31, 2017

Bell 206B, N43CM, DC Helicopters Incorporated: Accident occurred March 24, 2015 in Taylors Island, Maryland

Ronald Lopes of Staten Island, New York gives a thumbs up at Denny's in Cambridge, Maryland,  with Vincent Giglio of Howell, New Jersey, who safely landed the helicopter they were flying in Tuesday, March 24, 2015 after it lost engine power near the mouth of the Little Choptank River.





The National Transportation Safety Board did not travel to the scene of this accident. 

Additional Participating Entities:
Federal Aviation Administration / Flight Standards District Office; Baltimore, Maryland
Rolls Royce; Indianapolis, Indiana
Bell Helicopter; Lexington Park, Maryland

Aviation Accident Final Report - National Transportation Safety Board: https://app.ntsb.gov/pdf

Investigation Docket - National Transportation Safety Board: https://dms.ntsb.gov/pubdms

Aviation Accident Data Summary - National Transportation Safety Board: https://app.ntsb.gov/pdf

DC Helicopters Incorporated: http://registry.faa.gov/N43CM 

NTSB Identification: ERA15LA179
14 CFR Part 91: General Aviation
Accident occurred Tuesday, March 24, 2015 in Taylors Island, MD
Probable Cause Approval Date: 03/06/2017
Aircraft: BELL 206B, registration: N43CM
Injuries: 2 Uninjured.

NTSB investigators may not have traveled in support of this investigation and used data provided by various sources to prepare this aircraft accident report.

The commercial pilot reported that the helicopter was in cruise flight when he heard a "loud bang," which was followed by a partial loss of engine power. He performed an autorotation to shallow water near a shore, where the tailboom sustained substantial damage. A postaccident examination of the airframe and engine, which included an engine operational check, revealed no evidence of any mechanical malfunctions or failures that would have precluded normal operation. The loss of engine power that occurred during the accident flight could not be duplicated during a test run. Following the engine test run, the fuel control unit (FCU) was removed and tested separately. Tests revealed that the FCU operated erratically due to a bellow anomaly. However, because this condition was discovered only after the engine had successfully completed its test cell runs, a direct correlation could not be drawn between the condition of the FCU and the reported loss of engine power.

The National Transportation Safety Board determines the probable cause(s) of this accident as follows:
A partial loss of engine power during cruise flight for reasons that could not be determined because postaccident examination of the airframe and engine did not reveal any anomalies that would have precluded normal operation.




On March 24, 2015, about 1730 eastern daylight time, a Bell 206B, N43CM, was substantially damaged during an autorotation near Taylors Island, Maryland. The commercial pilot and one passenger were not injured. Visual meteorological conditions prevailed and no flight plan was filed. The helicopter was registered to and operated by DC Helicopters Incorporated as a personal flight, which was conducted under the provisions of Title 14 Code of Federal Regulations Part 91. The flight originated from Monmouth Executive Airport (BLM), Farmingdale, New Jersey, about 1530.

The pilot reported that the helicopter was in cruise flight at 3,000 feet above ground level, when there was a sudden drop in altitude followed by a 90 degree rotation to the left and a loud "bang." The pilot lowered the collective and noted that the torque gauge went below 10 percent. He then rolled the throttle to idle, entered an autorotation and landed on a shore.

Postaccident examination of the helicopter by a Federal Aviation Administration (FAA) inspector revealed that the helicopter's tailboom was buckled near the tail rotor gear box. Further examination revealed that the tail rotor drive shaft was broken.

Flight control continuity was confirmed by hand movement of the controls. The cyclic exhibited free movement in all quadrants and the collective exhibited free up and down movement. Corresponding control movement was observed up to the main rotor hub assembly. The tail rotor pedals were moved and control movement was seen at the tail rotor. Drive continuity was established through the drive system with movement observed to the main mast and to the tail rotor drive system. The tail rotor driveshaft on the tailboom exhibited a torsional crack. The tailboom exhibited evidence of tail rotor blade strikes. Both fuel boost pumps were shown to operate when the battery was turned on. The airframe fuel filter was removed and found to be filled with clear and clean fuel and the filter was also clean. The fuel valve was in the off position and motored on when the battery and fuel valve were switched on. The boost pumps were then energized and a steady flow of fuel was present out the "IN" line to the airframe fuel filter.

During a postaccident examination of the engine all B-nuts and fittings were checked by hand for torque, and none were loose. The bleed valve was checked by hand for proper operation. The valve operated smoothly with no lateral play of the poppet valve. The engine mounts were intact with no apparent deformities. The engine exhibited no evidence of having been damaged during the accident sequence. The engine cowlings were removed to facilitate examination of the compressor inlet. Examination of the compressor revealed no evidence of compressor damage or failure. Both the N1 (compressor) and N2 (power turbine) rotor systems were rotated by hand. The N1 rotated smoothly with no unusual noise or resistance. Continuity from the compressor through the auxiliary gearbox to the starter/generator was confirmed. Rotation of the N2 confirmed continuity to both the main rotor and tail rotor drives.

The engine was removed to be run in a test cell in an attempt to replicate the reported loss of power. A pre-run examination of the engine found no anomalies with the engine, or any damage which might preclude running the engine on a test cell. The engine was installed on a test cell, started, ran normally and met all serviceable engine standards. The engine produced normal power and responded properly to all power demands, including wave-off and sudden throttle and load changes.

After the engine test run, the owner of the helicopter sent the engine's fuel control unit (FCU) out for testing. During testing it was noted that one of the technicians found a "slight bend" in the FCU bellow's assembly. The condition of the bellows did not warrant rejection, and the FCU was reassembled and tested in accordance with manufacturer's specifications. During the test it was noted that the FCU performed erratically on the test stand, and failed to meet serviceable standards. The bellows assembly was replaced with an overhauled bellows assembly, and the FCU performed satisfactorily. The subject bellows assembly was then installed on a serviceable FCU, tested, and failed to pass serviceable standards.



NTSB Identification: ERA15LA179
14 CFR Part 91: General Aviation
Accident occurred Tuesday, March 24, 2015 in Taylors Island, MD
Aircraft: BELL 206B, registration: N43CM
Injuries: 2 Uninjured.

This is preliminary information, subject to change, and may contain errors. Any errors in this report will be corrected when the final report has been completed. NTSB investigators may not have traveled in support of this investigation and used data provided by various sources to prepare this aircraft accident report.

On March 24, 2015, about 1730 eastern daylight time, a Bell 206B, N43CM, was substantially damaged during an autorotation near Taylor Island, Maryland. The commercial pilot and one passenger were not injured. Visual meteorological conditions prevailed and no flight plan was filed. The helicopter was registered to and operated by DC Helicopters Incorporated as a personal flight, which was conducted under the provisions of Title 14 Code of Federal Regulations Part 91.

According to the pilot, he was in cruise flight at 3,000 feet above ground level, when there was a sudden drop in altitude followed by a 90 degree rotation to the left and a loud "bang." The pilot lowered the collective and noted that the torque gauge went below 10 percent. He then rolled the throttle to idle, entered an autorotation and landed on a shore. 

According to the Federal Aviation Administration inspector that examined the helicopter, the tail boom was buckled near the tail rotor gear box. Further examination revealed that the tail rotor drive shaft was broken. The helicopter was recovered and is awaiting further examination.

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