Biennial Transponder Inspection FAR 91.411 & 91.413 IFR Certifications

The IFR Pitot Static Inspection Consists of:


1) Inspect Altimeter - Various test are performed on the altimeter including Scale Error Test typically to 20,000 foot.


2) Leak Check of the Pitot & Static System - Unpressurized and pressurized aircraft's Pitot & Static Systems are both required per FAA regulation to pass Pitot Static System Leak Checks. Pressurized aircraft are tested at much higher altitudes than their unpressurized counterparts. Their allowable leak rates are much smaller (usually 2% of simulated altitude loss in one minute).  Unpressurized airframe pitot static systems must be evacuated to an altitude equivalent to 1000 feet above airfield elevation and the static system must not drop more than 100 feet in one minute as indicated on the altimeter.


3) Encoder (Mode C) Data - Transponder to Encoder Altitude Data Code lines are tested at every altimeter test point to the maximum ceiling of the IFR Pitot Static Test. This test is done at the same time as the altimeter test is done.


4) Transponder Inspection - The transponder inspection consists of testing of the radio portion of the transponder. Functions such as Frequency, Power Output and Side Lobe Suppression are scrutinized during this test.