for the correct type of instrument. This manual
lists the part number of the instrument.
troubleshooting charts.
If you cannot find an exact replacement for
an instrument, an interchangeable instrument may
INTERCHANGEABILITY OF
sometimes be used to prevent delay in returning
INSTRUMENTS
an aircraft to service. Aviation supply items
with the same stock numbers are operationally
You need to be careful when substituting
interchangeable, regardless of the manufac-
aircraft instruments. Check the illustrated parts
turer or the manufacturer's part number. An
breakdown (IPB) manual for the specific aircraft
Table 6-4.-Troubleshooting Chart--Airspeed Indicator