The approval process

Several LAA members have recently questioned the need for such a document-heavy approach to approval when at least some of the necessary information could more easily be gleaned by practical demonstration. As with most good ideas, the LAA has followed up on this and a more practically based process is in development.

Many modern glass-panel systems, and indeed more than a few retrofit upgrades, come complete with internal back-up batteries. These systems, if properly installed and maintained, completely remove dependence on alternators and main batteries and, as such, need a less complex assessment of the electrical system.

The LAA IFR team is currently working on an approval based on inspection of the installed systems in place of some of the more complex investigations and calculations. The process is not yet finalised, but may include a physical duration test of the various systems on the ground. In simple terms, will the required systems continue to operate for 45 minutes without the engine running? Why 45 minutes you might say, CS-23 only requires 30 minutes of reserves? The simple answer is that all the commonly available back-up systems are capable of at least 60 minutes and the extra 15 minutes over and above the required duration gives a margin of safety to take account of the inevitable loss of capacity with age that will be experienced with all batteries.

In addition to endurance checks, there will be a requirement to physically assess the aircraft for single points of failure. Do both radios switch off when the avionics-switch is opened? How is a trim runaway dealt with? Think of this part of the assessment as a practical Failure Modes and Effect Analysis while sitting in the cockpit.

The first aircraft are going through this system now and, once approved, it is hoped the process can be extended to all suitable aircraft.

It should also be noted that there has always been a fast-track process for aircraft previously type-certificated aircraft historically cleared to fly IFR. In simple terms, if the aircraft has previously held IFR certification and it can be shown to be in substantially the same configuration as it was when certified, the process is quite simple. There are some caveats. For obvious reasons, aircraft originally certified under some very old standards with a primary and back-up AI both powered from a single venturi, are required to fit an alternative power source for one AI and accept strict limits on OAT to ensure they are not impacted by icing.