Casualties unknown

Helicopter Crash Due to Uninstalled Cyclic Interconnect Tube (N3536T)

Cameron, LA, US

On November 19, 1990, a Mbb BO 105CB4 (registration N3536T) operated by Petroleum Helicopters, Inc. was involved in an aviation accident near Cameron, LA. Investigators recorded the probable cause as: Maintenance personnel's failure to install the cyclic interconnect tube after removing the dual controls, which resulted in a loss of control. This summary draws on records from the U.S. National Transportation Safety Board (NTSB) historical archive; 8 related events involving the same aircraft type or operator are linked below.

Sourcesthe U.S. National Transportation Safety Board (NTSB) historical archivePrimary reportUpdated 2026-06-10Data APIEditorial standards

A helicopter crashed after the pilot lost control during a right turn. The accident was caused by maintenance personnel failing to install the cyclic interconnect tube after removing dual controls.

What happened

The pilot lifted the helicopter off the helipad and initiated a turn to the right. As the aircraft climbed to approximately thirty feet, it began to nose slowly downward before rolling to the right. The helicopter then descended in an uncontrolled manner, impacting the terrain and striking several cars in an adjacent parking lot. During the impact, the pilot was thrown from the cockpit because his seatbelt failed. It was noted that he was not wearing a shoulder harness at the time of the accident.

The investigation

A post-accident examination of the aircraft revealed a critical maintenance error. Company maintenance personnel had previously removed the dual controls from the helicopter but failed to reinstall the cyclic interconnect tube. This missing component prevented proper control linkage between the pilot and co-pilot stations, rendering the aircraft unmanageable during flight.

Findings

The primary factor contributing to this accident was the failure of maintenance personnel to install the cyclic interconnect tube. This omission occurred after the dual controls were removed, creating a direct mechanical deficiency that led to the loss of control. The pilot's inability to maintain attitude and heading resulted in the fatal crash.

Safety message

This incident highlights the critical importance of verifying all maintenance actions are completed correctly. Ensuring that all components, such as interconnect tubes, are properly installed after any modification or removal is essential for flight safety.

Probable cause

Maintenance personnel's failure to install the cyclic interconnect tube after removing the dual controls, which resulted in a loss of control.

Investigation report by the U.S. National Transportation Safety Board (NTSB) historical archive. Original record: https://carol.ntsb.gov/event/20001212X24612. This page is a structured re-presentation; facts and quotes are in the National Transportation Safety Board (NTSB), United States.