Pilot Debrief

CONTINENTAL COPTERS INC. TOMCAT MK5A near Arlington, MN — 2013-09-06

Final reportCEN13LA537
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Date
2013-09-06
Location
Arlington, MN, USA
Aircraft
CONTINENTAL COPTERS INC. TOMCAT MK5A
Registration
N9005T
Category
Helicopter
Highest injury
None
Fatalities
0
Phase of flight
Maneuvering

Probable cause

The pilot’s failure to maintain control of the helicopter while maneuvering when he removed his hand from the collective control while plugging in his radio connection to his helmet, which resulted in the collective moving to the full-down position.

NTSB narrative

After taking off, the pilot applied pesticides to a field and proceeded to the next field located about 3 miles away. While en route, the pilot wanted to call his truck driver over the two-way radio. However, the radio connection to his helmet was unplugged, so he reached to plug it in with his right hand while his left hand transferred from the collective to the cyclic. Immediately after he plugged in the radio connection to his helmet, the collective slammed into the full-down position. The pilot then quickly grabbed the collective and raised it up. He noticed that the helicopter was losing altitude, that the main rotor rpm was decreasing, and that the engine rpm and main rotor rpm needles were split. He twisted the throttle control back and forth with no effect and then attempted to autorotate. The helicopter touched down hard, which resulted in substantial damage to the tailboom. Examination of the helicopter did not reveal any mechanical anomalies that would have precluded normal operation. Also, a review of the maintenance logbooks for the helicopter did not show any entries regarding malfunctions with the collective control during previous flights, and the helicopter operated normally during the first flight of the day. The pilot stated that he could have chosen to not unplug his helmet and keep his hand on the collective control at all times, which would have prevented the collective from slamming down while he was connecting his radio cables to his helmet. This model helicopter does not have a friction control mechanism on the collective control, and, if it is not held in place by the pilot, it can move up or down during flight. It is likely that, when the pilot removed his hand from the collective control and was distracted with plugging in his helmet radio connection, the collective moved to the full-down position and that he did not have enough altitude to recover the helicopter.

Analysis

Primary failure mode
Human factors
First missed decision gate
Pilot could have kept hand on collective while plugging in radio.

NTSB coding

Evidence available

  • 3 docket documents
View NTSB final reportView NTSB docket

Docket documents3

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