How to Choose an Avionics Shop for Your Aircraft

Your aircraft needs new avionics. Maybe a glass panel, a new autopilot, a transponder or a satellite phone. The shop you pick decides how well it works, how long the aircraft sits on the ground and what the paperwork looks like when you sell. This guide shows how to choose.

What an avionics shop does

Avionics are the electronic systems on an aircraft. Radios, navigation, displays, autopilot, weather radar, transponders and cabin connectivity. An avionics shop installs, repairs and tests this equipment. Some shops are part of a larger maintenance company. Others do only avionics.

Check the approval first

In the US, a shop that installs or repairs avionics for other people normally holds an FAA repair station certificate under Part 145. Avionics work falls under the Radio and Instrument ratings, and often a Limited rating for specific equipment. Ask for the certificate number and the ratings. Our guide on what a Part 145 repair station is explains how to read them.

In Europe, look for an EASA Part-145 approval that lists avionics in its scope. If your aircraft is registered in a different country from the shop, ask how they will release the work for your registry.

Manufacturer dealer status matters too. Garmin, Honeywell, Collins Aerospace and Universal Avionics all have authorised dealer networks. A dealer gets training, technical support and warranty access that a non-dealer does not. Check the maker's own dealer locator, not only the shop's website.

STC or Form 337: how the install gets approved

Every change to a certified aircraft needs approval. For avionics there are two common paths.

• Supplemental Type Certificate (STC). The equipment maker has already proven the install on your aircraft type. The shop follows the STC data. This is the cleanest path and the easiest to explain to a future buyer.
• Field approval. There is no STC for your combination of aircraft and equipment. The shop writes up the change on FAA Form 337 and an FAA inspector approves it. It takes longer and depends on the local FAA office.

Ask which path applies to your project before you agree a price or a date. A shop that says it will work that out later has not planned the job.

Experience on your type

A rating says the shop may do the work. It does not say they have done it on your aircraft. Wiring, antenna placement and panel layout differ a lot between a Cessna single, a King Air and a Challenger. Ask how many of your type they have completed in the last two years, and ask to speak to one of those owners.

Downtime

A full panel upgrade can keep an aircraft on the ground for weeks. Ask for a written schedule with a start date and a return date. Ask what happens if parts are late. Ask whether the shop will start on your aircraft the day it arrives, or whether it will wait behind other jobs.

If you fly for business or charter, downtime is money. Some owners combine the avionics work with a scheduled inspection so the aircraft is down only once. Our how to choose an MRO guide covers how to plan that.

The quote

A good avionics quote lists:

• Each piece of equipment with a part number and a price.
• Labour hours and the hourly rate.
• The approval path, STC or field approval.
• Any structural or electrical work the install needs, such as a new antenna or a bigger alternator.
• Removed equipment and whether you keep it or trade it in. Used avionics have resale value.
• Warranty terms on both parts and labour.

Compare at least two quotes. If one is much lower, check what it leaves out.

Paperwork when you sell

Avionics upgrades add value only if the records are clean. Make sure you get the logbook entries, the STC paperwork or the approved Form 337, updated weight and balance, and an updated equipment list. A buyer's inspector will ask for all of them. Our pre-purchase inspection guide shows what they look for.

Six questions before you sign

1. What is your repair station number and which ratings cover this job?
2. Are you an authorised dealer for the equipment I want?
3. Is there an STC for my aircraft, or will this be a field approval?
4. How many of my aircraft type have you done this on?
5. What is the fixed return date, and what happens if you miss it?
6. What is the warranty, and who do I call if a display fails six months later?

Sources: FAA, 14 CFR Part 145 and FAA Form 337 guidance (faa.gov); EASA Part-145 (easa.europa.eu); manufacturer dealer programmes (Garmin, Honeywell, Collins Aerospace, Universal Avionics).

Need an installer? Browse shops in our Avionics directory.