Sandia Aerospace SAC 7-35 - Manual (Page 17)

3.4 STATIC AND PITOT PORT CONNECTION
Standard 1/8 - 27 NPT brass fittings are provided on the front plate of the SAC 7-35 for attach-
ing to the aircraft static and pitot systems. An adapter may be used to convert these to match the
aircraft static and pitot plumbing. When attaching the mating fittings, make sure that they are
secure and free from leaks that can induce errors in the static and pitot systems. To reduce the
likelihood of the brass fitting rotating while installing the static line, a “D” shaped hole is used
to mount the brass fittings into the front panel. Upon completion of the installation of the SAC
7-35, a Case Leak test is to be performed per FAR Part 43 Appendix E.
NOTE: Since significant force can be applied to the SAC 7-35
during static and pitot fitting installation, dual wrench techniques
are always recommended to avoid damage to the airdata com-
puter.
3.5 OUTSIDE AIR TEMPERATURE (OAT) PROBE INSTALLATION
The SAE 7-35 is supplied with the STP 78 OAT probe P/N 305561-91. Avoid mounting the
OAT probe in or near prop airstream, engine or heater exhaust, transmitting antennas or on dark
painted surface. Failure to do so will result in improper OAT readings. The OAT probe re-
quires a 7/16” hole be drilled in the skin of the aircraft. The installer should consider fabricating
an appropriate doubler plate in accordance with accepted installation practices as outlined in
AC 43.13-1B. Skin thickness including doubler should be a minimum of 0.050” and a maxi-
mum of 0.188”. See figure 3-4 for mounting details. The OAT probe comes with a three wire
pigtail approximately 2 feet in length. The installer can cut this cable to length or extend it by adding
additional wire. Make sure that any connections are away from areas that can accumulate water or
chemicals.
Figure 3-3
STP 78 OAT Probe Dimensions
16
305561-91