Ice and Rain Minimum Qualification Standards for Pitot and Pitot-static Probes
This SAE Aerospace Standard (AS) establishes minimum ice and rain performance criteria for electrically-heated pitot and pitot-static probes intended for use on the following classes of fixed-wing aircraft and rotorcraft. The classes of fixed-wing aircraft are defined by aircraft flight envelopes and are shown in Figure 1. The flight envelopes generally fall into the classes as shown below:
Class 1: Cruise altitude ≤ 23 000 feet
Class 2: Cruise altitude ≤ 31 000 feet
Class 3: Cruise altitude ≤ 42 000 feet
Class 4: Cruise altitude > 42 000 feet
Class R: Rotorcraft
The user of this standard must evaluate the aircraft level installation requirements for the probe against the class definition criteria to ensure adequate coverage for the application. It may be necessary to step up in class or modify the test conditions in order to meet the applicable installation requirements.
NOTE: Class 2 is divided into two subgroups identified as either Class 2a or Class 2b. Class 2a probe applications typically include aircraft that operate within the mid to lower end of the Class 2 altitude range and that only use probe output to display basic airspeed and/or altitude. As such, Class 2a probes do not have to test ice crystals at an altitude-capable icing tunnel. Class 2b applications are for probe installations intended to serve a critical function and should be tested at an altitude-capable icing tunnel. Probes qualified to Class 2 of this standard shall be identified as either Class 2a or Class 2b.
In addition this performance standard applies only to the probe types listed below and is limited to only the performance of the probe itself as defined from the aerodynamic sensing aperture on the probe to the aircraft pneumatic interface connection.
Type I – Pitot Pressure, Straight and L-Shaped
Type II – Pitot and Static Pressures, Straight and L-Shaped
NOTE: This specification, when used in conjunction with AS8006, provides a comprehensive design and test standard for the devices that fall within the scope of this document.
NOTE: This document is technically equivalent to EUROCAE ED-225, dated TBD.
Rationale: This standard provides a consistent means to evaluate electrically heated pitot and pitot-static probes for in-flight ice and rain conditions that may be experienced in service. This standard does not address other functions that are sometimes combined with pitot and static pressure measurements, such as aircraft AOA.