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Do Ercoupes need TSO'd instruments?

Disclaimer: We have no professional or expert qualifications of any kind.
It's fully up to you to check any information you find here with
standard aviation industry sources such as aircraft maintenance
manuals, flying instruction books and, above all, FAA regulations!


In her struggle to comply fully with the regulations while installing the same lower-cost instruments used in the experimental aircraft fleet, Linda Abrams found the references listed in this file:

The first section is the second page of Aircraft Specification A-718 which governs the 415-C and 415-CD models, in the section titled Specifications Pertinent to all Models.

Type Certificate Data Sheet A-787, which governs all the later models of Coupes, contains the exact same critical wording.

The next section has excerpts from the Civil Aeronautics Manual 4a which specifies the exact requirements governing manufacture of our aircraft, including instruments.  Linda has highlighted the section pertaining to airspeed indicators.

With this information, Linda has received approval from her regulation-strict A&P-AI to install a non-TSO airspeed indicator.  Feel free to print this information and put it in your aircraft documents binder for use in consultation with your own A&P-AI.

Thanks, Linda!


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Here is some info from the EAA on TSO requirements . . . (thus expensive instruments). 

As you can see, they are not required in the ercoupe. So inexpensive NEW altimeters can be installed, and are available from all of the parts folks.. like Wag Aero...their catalog lists a 0 - 20,000 ft altimeter   # 064-000 at $202.75....I'm sure others also have similar non-TSO altimeters at low prices.... 

Best of luck 
Harry Francis


letter folows:

From: Joe Norris
To: Matt at LA Sport Aviation
Sent: Monday, May 05, 2008 1:56 PM
Subject: RE: TSO'd question

Hello Matt,
You will find no requirement in any regulation that requires any
piece of equipment to be built under a TSO authorization (commonly
referred to as "TSOed"). However, some regulations require that a
piece of equipment "meet the requirements" of a TSO. Examples would
be transponders and IFR GPS units. But for the most part there is
no requirement that any particular piece of equipment be "TSOed".
Of course the installation of the equipment might need to be
approved, such as modifying an instrument panel when the panel is a
structural member of the fuselage, or when changes to the primary
structure must be made to accommodate a particular piece of
avionics. But the unit being installed does not necessarily have to
be "TSOed".
(This has nothing to do with whether the aircraft manufacturer is
still in business or not.)
You do have to make sure that the certification of the aircraft
doesn't specifically prohibit or require certain equipment to be
installed, but in the case of an Ercoupe that wouldn't be an issue
(but can be an issue with later FAR Part 23 certificated aircraft).
Joe Norris
EAA 113615 Lifetime
Senior Aviation Specialist
EAA Aviation Services
Phone: 888.322.4636 Extension 6806
Fax: 920.426.6560