Avionics and connectivity

Avionics purchasing turns on a distinction that catches buyers from other industries every time: the approval of the box and the approval of the box on your aircraft are separate things, held by possibly separate companies, and a supplier can be entirely honest about the first while leaving you to discover the second.

The article and its authorisation

A technical standard order sets a minimum performance standard for a class of article, and a TSO authorisation is the FAA's approval for a manufacturer to produce the article to it.¹ The authorisation covers design and production of the article itself; putting the article on a type-certificated aircraft takes its own approval.¹ So the first question to a supplier is which approvals its equipment carries, and the second is what approval path exists for your airframe: a supplemental type certificate, an approved model list, or fitment under the aircraft's own type design.

The FAA publishes its design approvals, so the claims are checkable: TSO authorisations, parts manufacturer approvals and supplemental type certificates can all be looked up in the agency's own system.² A supplier whose approval claims do not appear in the register has a conversation to have before you do.

The software underneath

Modern avionics is software with a bezel. Airborne software is developed against design assurance guidance published by RTCA, and the design assurance level tells you how much rigour went into the code for the function it performs.³ You do not need to audit that yourself; you need the supplier to say plainly what level each function was developed to and to show the environmental qualification of the hardware, which is tested against RTCA's environmental conditions standard.³ Vague answers here are a real signal, because a company that has done this work is proud of it and specific about it.

Support is the long half of the price

An avionics purchase lives for decades. Ask how long the supplier commits to repairing the unit, what the exchange pool looks like, and what happens when a component inside the box goes out of production. Ask what the software update path is and what an update costs. Ask whether the databases the unit depends on come from the supplier or a third party, and what the subscription runs. A cheap box with an expensive database is not a cheap box.

Questions that sort suppliers

Ask for the approval numbers and check them in the register.² Ask which functions carry which design assurance level.³ Ask who holds the installation approval for your aircraft and who does the certification work if none exists. The suppliers listed below appear on public facts, each line linking to its source; the approvals conversation goes faster when you have already read them.