Pitot/Static, Transponder, Altimeter, Altitude Encoder and ADS-B Requirements

Transponders are required to be inspected by an FAA Certified Repair Station
every 24 calendar months according to FAR 91.413 in accordance with FAR 43
Appendix F.  If you have an altitude encoder interfaced to your transponder,
the correlation must be checked with your altimeter at the same time according
to FAR 91.411 in accordance with FAR 43 Appendix E Part c.  Other information
on altitude reporting systems can be found in FAR 91.215, 91.217 and AC 43-6C.
Even if you only fly VFR your transponder, encoder/altimeter correlation, and
pitot/static system still must be checked by Federal Law.  Anytime your transponder
is in the ALT position, it will be sending signals to air traffic control, as well as, other
aircraft with traffic advisory systems telling them your altitude.  If you don't have the
altimeter/encoder coorelation checked, your transponder may be sending them
incorrect altitude information.  This should be correct for the safety of everyone under
air traffic control and flying with traffic advisory systems.  In addition to the above, to
fly in IFR conditions, the altimeter must be recertified according to FAR 91.411 in
accordance with FAR 43 Appendix E.

The following refers to non-charter general aviation aircraft. ADS-B Output will be
required January 1, 2020 for aircraft that will be flying into Class A (18,000 ft and above),
Class E (10,000 ft to 17,999 ft), Class B or above (Very Large Airports), Class C or above
(Large Airports) airspace and 30nm Mode C rings or above.  ADS-B Output will also be
required when flying within 12nm off the US shore and above 3000 feet MSL. ADS-B Output
will not required in Class E (10,000 ft to 17,999 ft) airspace IF you stay below 2,500 feet
AGL, for example flying over mountains. ADS-B will not be required to fly into Class D
airspace or uncontrolled airfields, as long as they are not located within a 30nm Mode C ring
and you stay out of Class B and Class C airspace. To clarify, you will not be able to fly above
Class B or Class C airspace either without ADS-B Output.  See picture below.  That being said,
there are approximately 87,000 flights in the US per day. ADS-B Output gives ADS-B Input
equipped aircraft traffic information on their position, altitude and direction of flight. This
makes the aviation community much safer. With ADS-B Input you would receive traffic and
weather information for free right now! FAR 91.225 is the rule on ADS-B Output equipment.

ADS-B Output requires a WAAS GPS positioning source. Unless you have a WAAS GPS, your
GPS cannot be used for ADS-B Output positioning. In that case, you would have to go with an
all inclusive ADS-B system which has a built-in WAAS GPS receiver, display/controller and a
WAAS GPS antenna would have to be mounted on your aircraft. These are referred to as UATs.
They transmit on 978MHz.  Some models transmit on 978MHz and 1090ES. In most cases,
you could keep your existing Mode C transponder if you installed a UAT.  A separate UAT antenna,
which is a transponder type antenna, would be installed on your aircraft. All transponders transmit
on 1090MHz, however, ADS-B Output Mode S transponders use an extended squitter and are
referred to as 1090ES. They utilize one tranponder antenna. In order to utilize an ADS-B Output
transponder, a WAAS GPS receiver must exist or would have to be installed in your aircraft.
1090ES will be required in Class A (18,000 ft and above) from either a Mode S transponder with
ADS-B Output or a UAT which transmits 1090ES, and would suffice in all other airspace.  In all
other airspace (below 18,000 ft), a UAT which transmits on 978MHz would suffice.  FAR 91.217
states that an ADS-B UAT must receive the same altitude reporting information as the transponder.
So, the same encoding altimeter, blind altitude encoder or air data computer must be interfaced
with the transponder and the ADS-B unit.  Several ADS-B UATs provide ADS-B Output and Input
and are referred to as ADS-B transceivers. They will display on various WAAS GPS units and Multi-
Function Displays. Separate WiFi or BlueTooth units can be installed to receive ADS-B Input
information on iPads and other handheld devices.

Lafayette Avionics, Inc. is a full service avionics facility, FAA Certified
Repair Station with Class I, II, III, limited instrument, and limited airframe
ratings, that can perform the required transponder and altitude reporting
inspections for you. They can also install ADS-B in your aircraft.

Give us a call at (765) 743-3828 for information on  all  your
avionics needs.  The FAX number is (765) 743-0000.

Hoping we can be of service,


               Ron and Josh

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