How to Prepare for Your Permit Inspection

Paperwork

About 1/3 of the work in revalidating a permit to fly involves the paperwork. It makes the inspection much easier if the following are in place for example:

Logbooks complete and up to date?

Registration certificate/permit to fly/limitations certificates available?

Operator’s handbook available?

Batten plan?

Modifications approved and logged?

Weight and balance report up to date, logbook entry?

Maintenance up to date, logbook entries?

Mandatory permit directives (MPD’S) up to date, complied with?

Engine and airframe service bulletins actioned and recorded?

Compass swing within date?

Radio licence valid?

Physical inspection

Cleaning and lubricating the aircraft is a good way to find faults. Work progressively around the aircraft, much like a “gold standard” preflight inspection. Don’t let anyone distract you.

Move and wiggle joints - ensure there are no loose fasteners and that split pins/rings are in place.

Have a good overall look at the aircraft for symmetry - for example if one wing is low there could have been a heavy landing and undercarriage damage.

Does the spinner line up with the cowl? if there is a mismatch, there could be a damaged engine mount or noseleg mount.

Check controls are full and free and move in the correct sense, including trim tabs.

With a clean aircraft it is much easier to spot fatigue cracks - look especially around engine and undercarriage mountings.

Some areas can only be inspected with a borescope or by disassembly. It is a good idea to remove the bolts and slide a flexwing roll bearing along the keel to look for cracks at the bolt hole edge. Some areas can usefully be inspected with a mobile phone inside a structure.

Is the wiring tidy and secure? Untidy and loose wiring can be especially hazardous in carbon fibre airframes where a short circuit can cause a fire.

Tyre pressures/condition? brake pads? Move the aircraft on it’s wheels and check suspension condition and function.

Wooden propellers shrink and swell - are the bolts present and at the right torque?

Control cable tensions? This can change seasonally in wooden aircraft.

Sails

Aircraft with sails can be subject to UV light degradation. The main body fabric can be affected as well as the stitching. Polyester sails and stitching tend to be affected the most. Kevlar (Aramid) is particularly prone to strength loss through UV light breakdown.

Sails must be protected from UV light as much as possible - a cover (e.g. an old sail) is a good investment.

For these materials an objective strength test with a Bettsometer or Brooks meter is necessary.