Sikorsky S61 Visits Maxcraft

1978 Sikorsky S61N

The S61 Fits Perfectly in the Maxcraft Hangar

Aircraft & Owner:

Canadian Helicopters is the largest helicopter transportation services company in Canada with 25 bases and a fleet of over 90 light, medium, and heavy lift helicopters. The Sikorsky S-61N is the civilian version of the Sea King military helicopter. The N model is capable of being amphibious, however this specific aircraft has had the landing gear replaced with the non-amphibious “L” model gear. Designed primarily for passenger transportation, the S61 can seat up to thirty passengers. This helicopter is impressive in size at over 58 feet in length, with five 31 feet long rotor blades.

Need:

This installation was part of a two-helicopter upgrade plan to comply with ADS-B mandates in United States airspace as well as improving reliability. Installing this new transponder also required a supplemental type certificate (STC) to keep the aircraft certified.

NEW EQUIPMENT LIST

GTX 335	ADS-B Out Transponder (Garmin)
SSD120-30NE-RS232	Altitude Encoder (Trans-Cal)
LED Annunciator	ADS-B Fail Annunciator (Mil Spec)
SH20-31	Supplemental Type Certificate, Installation of Garmin GTX Transponder System (Maxcraft)

The Newly Installed Transponder in the Center Pedestal

The Seats are Removed to Provide Easier Access to Run Wire and Install the Transponder

Maxcraft Solution:

We opted to install the Garmin GTX 335 transponder which combines standard mode S and automatic dependent surveillance broadcast (ADS-B) into a single unit. We were able to interface the existing GPS 500W GPS to provide the position source data for the ADS-B transmissions. We also installed an LED remote annunciator on the main panel to indicate to the pilot in the rare occasion the ADS-B fails or has any issues. This is required when the transponder is outside the pilot’s primary field of view, and failures are not annunciated on other system displays. Maxcraft also revised our previously issued supplemental type certificate for installing the GTX transponders in the Sikorsky S61 for this installation.

The ADS-B Fail Annunciator on the Main Panel

The Story:

Our original plan for this project was complete installations in both helicopters by May of 2021, but due to one helicopter requiring extensive repairs and repainting, along with the other helicopter being required for operations, the timeline was delayed. When the operational helicopter was enroute back to the lower mainland, we arranged for it to stop by Maxcraft for this install before continuing its journey to receive heavy maintenance. After completing the install Maxcraft was able to perform the required STC validation test flight while enroute to the heavy maintenance facility.

The Transponder Installed and Powered on.

A fun fact about this specific helicopter is Maxcraft’s President Daryl MacIntosh worked on it in the early 1980s when Canadian Helicopters had it stationed in Thailand.