Estimated completion time including certification is another factor that could have a significant impact on what actually gets accomplished. Autopilot compatibility with newer generation flight systems is one thing that can cause a price estimate to quickly add numbers between the dollar sign and the decimal point (along with an extension to downtime) and may require a series of flight tests before certification is complete.
Last but not least is consideration of the financial contribution the aircraft owner is willing to make, along with determination of aircraft value after the project has been completed.
Choosing a manufacturer
Once it has been decided what features are to be added, it is worthwhile to make inquiries about which avionics manufacturers can accommodate the need. Some additional questions should be asked including the manufacturer’s ability to maintain the system once it is in service, as some use dealer networks to get their product distributed and supported. It will be worth knowing who will be the point of contact for service, operating hours, and typical lead time to deliver parts to customers.
If international borders separate equipment manufacturers from customers, then shipments will require a customs clearance. This has been known to add days to an AOG situation.
It is also worth inquiring about a loaner equipment pool. Manufacturers have different policies in the event of component malfunction during the warranty period. In some cases a new replacement will be issued, while in other situations a repaired or overhauled device may be supplied as a replacement. Consideration should be given that obtaining a device with similar time in service may not be easily achievable. It is also worth the time to verify that the specific equipment planned for installation is not unique to only one aircraft. That will definitely hamper possibilities of obtaining a timely replacement.
Interfacing with existing systems
A determination should be made regarding what equipment will remain. In some cases, the cost of interfacing existing devices with new technology may come close to or even exceed the price of a replacement. Often components such as coax cables and wiring are planned for continued use and if that is the case it should be predicated on their being thoroughly tested. Antenna coax does tend to degrade with age and replacing radios without changing the transmission line can result in less than desirable operation of the new device. Existing wire routing should also be analyzed. In some cases co-locating certain types of wire can result in electromagnetic interference (EMI).
In addition, adhering new wires along with existing bundles may present unwanted situations as excessive tightening of wire clamps, or tie wraps can compress insulation and alter the impedance of circuits. Existing splices and terminal connections should be inspected for security and general condition. A minor amount of dirt or corrosion in an electrical connection can have a significant impact to a circuit that may now be expected to carry milli-amp current flow. In the event low power digital weather radar is planned, it may well be worth the expense of having the radome either overhauled or tested to verify it will not hamper radar transmission.
Weight and balance should be considered along with a pre-installation calculation prior to finalizing a retrofit sales agreement. A recent situation occurred where a non-aviation savvy individual procured a helicopter and contracted a local shop to outfit it with all the latest equipment. Once completed, it was discovered that when fully fueled, the ship could carry the pilot and one-half a passenger with no luggage.
This may be acceptable if the aircraft is intended to carry only a few passengers short distances. Unfortunately, that wasn’t the case.
Consider impact of changes
Technology upgrades tend to supply many advantages. Newer equipment is frequently lighter in weight, consumes less electrical power, and produces less heat than predecessors. The above statement is not categorically true and does point out several factors.
A preview of the Electrical Load Analysis is a good starting point. Size and weight of components will influence location and structural attachment to the airframe. When determining the site for a new device, maintenance accessibility is an important factor. Equipment with a known high reliability may not require a position in the most convenient location, but if their planned installation does impede access to other devices, further consideration may be in order.
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