Avionics Retrofit Experiences to Avoid (and How...)

With a multitude of retrofits available for the flight decks of older business aircraft, the lure of an upgrade can be strong. Ken Elliott provides an outline on how to avoid ending up with an avionics retrofit experience you come to regret...

Ken Elliott  |  24th October 2023
Back to Articles
Ken Elliott
Ken Elliott

Ken Elliott is a veteran with 52 years of aviation experience, focussed on avionics in General and Business...

Read More
An Avionics Technician at work on a private jet flight deck


For corporate aircraft there are four situational changes that may involve or require avionics retrofits, upgrades or changes.

These include: 1) Continued airworthiness and operational improvement for your own aircraft; 2) Used aircraft pre-purchase maintenance and upgrades; 3) An operating category change between FAR Part 91, Part 91K and Part 135 requiring an equipage change; and 4) New aircraft post- delivery upgrades and changes.

For corporate aircraft avionics there are seven main circumstances that may lead to avionics retrofits, including:

1)    Obsolescence

2)    Software and hardware changes

3)    New capabilities

4)    New product availability

5)    Provisioning for future product upgrade

6)    The need to expand on existing capability

7)    Mandated or an operationally required upgrade.

Avionics retrofits range from simple additions (such as power outlets and USB ports) to complex avionics suite upgrades (impacting several major sub systems within the cockpit).

By the very nature of competitive marketing and required certification, most upgrades on offer are not necessarily something ‘to be avoided’, but different approaches to each upgrade may be preferable to others. There is also key guidance that can be applied to any upgrade.

Taking the four situational changes of an aircraft, and the seven avionics circumstances into consideration, unique dynamics come into play.

The Unique Dynamics of an Avionics Upgrade

One example of unique dynamics has occurred several times over the last 50-plus years, and it involves aircraft Original Equipment Manufacturers (OEMs) and their approach to fleets of production aircraft during a mandated equipage upgrade cycle.

OEMs may tout their own retrofit or upgrade program for continuity, compatibility, quality and an ability to provide worldwide product support.

This has tremendous merit and is certainly valid self-promotion when it comes to new and recent in-production aircraft models. However, the situation becomes murkier with older pre-owned aircraft models (a good example being the recent international government agency mandate for aircraft to upgrade for ADS-B Out).

Aircraft and avionics OEMs worked in unison to provide turnkey upgrades to their existing avionics packages, and, understandably, the newer the aircraft, the quicker the solution became available. In some cases they became available too quickly – proving to be premature...

ADS-B Out Version 0 and 1 were found to be inadequate and were later upgraded to Version 2, which necessitated an additional modification to any aircraft and equipment that were already provisioned or completed.

Despite the commendable proactive effort by OEMs regarding their more recent aircraft models, there appeared to be a lag in solutions made available to earlier aircraft models, opening the door for alternative third-party ADS-B Out solutions.

Dan Buzz (formerly with Duncan Aviation) set up CMD Solutions as one option, helping fill the void. This third-party provider designed and certified – via Approved Model List (AML) Supplemental Type Certificates (STCs) – economical solutions for no fewer than 38 models of pre-owned aircraft and their derivatives.

For their owners and operators, this provided an equal alternative to the OEM solutions as they later emerged.

Avoiding an Undesirable Avionics Upgrade: Key Guidance

For any retrofit there is key guidance that, if ignored, could result in an undesirable upgrade. Starting with Maintenance Repair & Overhaul (MRO) shop selection there are three choices:

  • Aircraft OEM (using its MRO division and possibly separate location, source by aircraft model).
  • Third-Party MRO Center (can be sourced via the National Business Aviation Association (NBAA) website or other regional Business Aviation association).
  • Avionics-specific MRO Center (can be sourced via Aircraft Electronics Association (AEA), which is US based but provides worldwide coverage).

For any MRO center you consider for the upgrade, ensure you check the following with respect to your aircraft and equipment:

  • MRO Capabilities List: An internally-created document showing the full capability of the MRO center and its partner entities.
  • MRO STC List: An internally-created document showing all STCs created and owned by the MRO center. If the MRO shop does not own the STC(s), check its record of STC implementation to your aircraft model.
  • OEM Approvals & Certifications at the MRO Shop: As an example, if you own a Gulfstream G550 and are considering a Honeywell avionics upgrade, does the MRO center have the approvals, training, manuals, test and hangar equipment, and the certifications for your aircraft and its avionics?
  • Repair Station Ratings: These are separate to OEM approvals. MRO centers, as repair stations, are required to obtain and maintain Repair Station Certificates, as issued by the airworthiness authority in the country where the MRO shop operates. There will be multiple ratings, and these must include those that will permit the MRO center to complete your retrofit. That includes certification for the repair station to work on your aircraft if it’s enrolled on a foreign registry.

Avionics Upgrade: The ‘Four Gates’ of MRO Selection

Once you’ve narrowed down your selection to those MRO centers that can complete your aircraft retrofit, there are four major ‘gates’ to navigate...

1. Schedule: MRO facilities mostly schedule work based on hangar and manpower capacity. There are increasingly more and larger corporate aircraft flying today all requiring corresponding hangar capacity.

Both the OEMs and the independent MRO centers are busy expanding their capacity, and the OEMs are also increasing their post-delivery capability in order to manage their fleets and better control procurement. When scheduling your avionics retrofit, avoid shops that cannot assure you of adequate hangarage throughout the visit, or where it’s evident manpower will be a problem.

Where possible, schedule major retrofits to align with major inspections. If scheduling with paint, however, plan carefully.

You do not want any external fuselage disruption after new paint completion. Moreover, during the re-paint, aircraft access is closed – so you cannot ‘double-dip’ on the schedule with an avionics upgrade during that same period.

Because the checkout and delivery phases of a project are always up against the clock, and unsuspected issues may need resolving, the aircraft operator should not schedule any trips immediately after the original scheduled completion of the upgrade. Add a two-day cushion, however painful that may be to your flight department.

Note: It will be difficult to add avionics during a pre- purchase inspection when brokers are keen to conclude a transaction. In that instance, try to close the sale and then keep the aircraft at the facility for any additional work.

2. Procurement: Supply chain constraints have impacted all industry sectors, and for aviation it goes deep into sourcing the components that are necessary to build the equipment for each aircraft. For retrofit considerations, ask questions on procurement, such as:

  • What are the lead times on the delivery of new equipment?
  • What is the availability of accessories, wiring, antennas and parts for avionics?
  • What is the process and turn-times for any equipment needing to be modified?

While there are bound to be risks, minimize them by knowing what they are, and how they can impact your schedule. Plan to avoid a retrofit fraught with delays, potentially grounding your aircraft for longer than necessary.

3. Engineering: For avionics retrofits, both electrical and mechanical engineering should be completed before your aircraft enters the hangar. Harnesses and other pre-build should also be waiting on the aircraft’s arrival.

Monitor the engineering progress between project approval and aircraft input to avoid delays and mistakes. And while STCs and factory Service Bulletins (SBs) are often sold as ‘plug-and-play’ ready, this may not ultimately be the case. Many aircraft require at least some modification or equipment change that may not be in the documentation or is listed as an easily missed caveat or sub-note.

4. Certification: This is perhaps the most likely area to look for avoidable pitfalls. Typically, the priority of certification goes to the aircraft in-house or to those with an issue that may arise post-delivery. Operators with pending upgrades should monitor the status of advance certification. In particular, look out for:

  • Potential delays connected with the airworthiness authority.
  • Concerns that could arise from dealing with subcontracted certification personnel (Designated Engineering Representatives – or DERs).
  • Processes that need additional time and steps that are dependent on previous steps awaiting approvals.

It may benefit you to create your own certification and release checklist to avoid an aircraft delay or a potential grounding. At the very least, after a retrofit, check the following have been issued or updated...

  • Instructions for Continued Airworthiness (ICAW)
  • Electrical Load Analysis (ELA)
  • Equipment List
  • Weight & Balance
  • Flight Manual Supplements (FMS)
  • Minimum Equipment List (MEL)
  • Avionics Prints
  • Any Form 337, 8110, and 8130
  • Activated Subscriptions, Software Updates & Databases
  • Registered Warranties, Additional Placards & Crew Training
  • Any STCs and all Logbook Entries.

To learn about specific avionics upgrade situations to avoid, continue reading this article in the AvBuyer MRO Special Industry Guide digital edition. Click the link below.

Do you have a specific aircraft maintenance, upgrade or repair need?

Use Advantage to outline your maintenance requirements by completing our quick form, and your enquiry will be passed to qualified service providers. Receive the feedback you need to help you choose the right partner and the best deal.
Start now

Related Articles

SHARE THIS ARTICLE

Print

Other Articles

Need Avionics Services?

Use AvBuyer’s Maintenance/ Upgrade Locator Service todayConnect now
Gulfstream G450
Please email
South Africa
Cessna Citation CJ1+
Please call
United Kingdom - England
Bombardier Challenger 604
Please call
India
Airbus ACJ330
Deal pending
Switzerland
Boeing 767
Make offer
United States - FL
Embraer Legacy 500
Deal pending
United States - TN
Hawker 800A
Please call
Mexico
Gulfstream G550
Please call
United Kingdom - England
Gulfstream IVSP
Make offer
United Kingdom - England
Dassault Falcon 7X
Make offer
Luxembourg
loder image