When many aircraft operators hear the word “Retrofit” it is often accompanied by an undeniable $$ KACHING $$ (sound of a cash register). When taken in the appropriate context, the word makes perfect sense: “To provide with parts, devices, or equipment not in existence or available at the time of original manufacture.” Of course, implementing any of those words in an aircraft always sounds expensive. A significant percentage of aircraft used in business and commercial aviation were manufactured prior to the turn of the century; with technology advancing at warp speed, it all too often becomes necessary to evaluate the capability of the equipment to fulfill present and future missions.
There are all kinds of reasons for upgrading business aircraft avionics: whether the change is mandated, or to take advantage of the latest technology that revolutionizes safety, communications, situational awareness or operational capability. In some cases, adding an electronic flight bag (EFB) may deliver many of the desired upgrades without the expense and downtime associated with complete retrofits.
Determining the criteria
So, what are the criteria to determine whether to renew, replace, or retire present equipment? Numerous factors should be considered, first of which is continued supportability of the airframe. A Hansa Jet for example, was considered by some to be a business jet that was ahead of its time when introduced into service in 1964. Production was limited to around 40 aircraft with fewer than a dozen in flyable condition today. A recent Airworthiness Directive limits the life of the aircraft to 15,000 flights or flight hours. Designing, engineering, and installing a new digital avionics suite and automatic flight control system for such an aircraft would be a sign the perpetrator has more dollars than sense.
It should also be understood that some aircraft and subsequent components have design life limitations. A few models, through ongoing evaluation, have been allowed to exceed the proposed life limits of their designers. Operators of those aircraft still have to contend with a little known factor called Commercial Life. The concept of producing and supporting components for as long as profit exists is a big part of a free enterprise system; as time goes by the spares inventories tend to evaporate, making the technician’s life more challenging. Some equipment manufacturers are willing to share their perspective regarding equipment life and this information should be solicited as part of project planning.
Recent or current production airframes, where at least several hundred have been produced, are often good candidates for upgrades and if the manufacturer can be involved in the process added value is almost certain. As most airframe manufacturers are in business to sell aircraft, it is often contrary for them to support refurbishment of out-of-production products. It will at least be advantageous to find out to what degree the airframe manufacturer will continue to support the machine once the retrofit is accomplished.
One question that is usually worth asking during the equipment selection process is: Has this been done before? And if so, in how many other aircraft of my type? Ingenuity is often a good thing but having a one-off type of aircraft can be another cause for elevated blood pressure in maintenance technicians when it comes to support and continued airworthiness.
Research and preplanning will be the key to success in any avionics refurbishment.
Project input should be solicited regarding the primary mission of the aircraft, along with an estimation of how much time the aircraft will be performing other than primary functions. That is, will the aircraft be used primarily for short trips within a specific geographic region and do a periodic overseas flight?
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