Twin Commander Aircraft LLC has engineered a solution to replacing certain wear items in Sundstrand Environmental Control Units used on various Twin Commander model aircraft.
The problem has been unavailability of replacement flexible hose couplings used in Sundstrand ECUs on the 690C, 690D, 695, 695A, and certain serial-number 695B Twin Commanders. The couplings connect metal piping in the ECU, and protect the piping from vibration and thermal expansion. The couplings are made from special materials to withstand the high temperatures and pressures. The largest of the couplings is about six inches long and four inches in diameter.
Twin Commander Aircraft recently designed, developed, and certified replacements for the couplings, and parts are available. The replacement parts are available in a kit (PK-880748), or can be ordered individually. However, it is recommended that if one coupling needs replacing, a full replacement set should be installed. Some units require five flexible hoses, some seven, depending on aircraft model and serial number.
For more information about the replacement Sundstrand couplings, contact your authorized Twin Commander Service Center.