Piper 88417-003 Environmental Control System (ECS) Crossover Tube Kit

The Piper 88417-003 Environmental Control System (ECS) Crossover Tube Kit is an upgrade was announced in Service Letter 1104 on March 14, 2008. It was designed to minimize potential fluctuations in cabin pressure and improve the accuracy of the flow control pressurization sensor. The basic concept behind the upgrade was to reduce down the crossover tube's diameter, thereby increasing the pressure and minimizing the work required by the subsequent parts in the system. This enabled a more accurate measurement of air flow and had less potential for deviations.

The upgrade was provided in two different kits. Kit #88417-002 replaces all parts with factory new components. Kit #88417-003 used overhauled parts and did not include the Mass Flow Sensor Assembly or the Mass Flow Controller, both expensive parts.