Bob
Actually reading the regs will prevent you from getting it wrong:-
technically he is not allowed to disturb any 'Locking Devices' such as locking wire or split pins or tab washers. If he does, he neds a Licensed Aircraft engineer, duly 'Type Rated' on the type, to certify the work carried out.
Not so. You can replace defective safety wiring or split pins excluding those in
engine, transmission, flight control and rotor systems
And as smarthawke says, your views on certification are out of date.
I'd refrained from publishing the full list of what you can do in the hope that people would look it up using the reference I gave. However here it is:-
Pilots maintenance—prescribed repairs or replacements
12. For the purposes of article 16(7)(a), the following repairs or replacements are prescribed—
(a) replacement of landing gear tyres, landing skids or skid shoes;
(b) replacement of elastic shock absorber cord units on landing gear where special tools are not required;
(c) replacement of defective safety wiring or split pins excluding those in
engine, transmission, flight control and rotor systems;
(d) patch-repairs to fabric not requiring rib stitching or the removal of structural parts or control surfaces, if the repairs do not cover up structural damage and do not include repairs to rotor blades;
(e) repairs to upholstery and decorative furnishing of the cabin or cockpit interior when repair does not require dismantling of any structure or operating system or interfere with an operating system or affect the structure of the aircraft;
(f) repairs, not requiring welding, to fairings, non-structural cover plates and cowlings;
(g) replacement of side windows where that work does not interfere with the structure or with any operating system;
(h) replacement of safety belts or safety harnesses;
(i) replacement of seats or seat parts not involving dismantling of any structure or of any operating system;
(j) replacement of bulbs, reflectors, glasses, lenses or lights;
(k) replacement of any cowling not requiring removal of the propeller, rotors or
disconnection of engine or flight controls;
(l) replacement of unserviceable sparking plugs;
(m) replacement of batteries;
(n) replacement of wings and tail surfaces and controls, the attachments of which are designed to provide for assembly immediately before each flight and dismantling after each flight;
(o) replacement of main rotor blades that are designed for removal where special tools are not required;
(p) replacement of generator and fan belts designed for removal where special tools are not required;
(q) replacement of VHF communication equipment, being equipment which is not combined with navigation equipment.
As with all things, while it may be legal for you to do something it my well not be sensible.
Also worth pointing out that these operations can only legally be carried out by the holder of a Pilot's License who is the owner or operator of the aircraft. From Art 16 of the ANO:-
(7) The circumstances referred to in paragraph (6) are:
(a) the only repairs or replacements in respect of which a certificate of release to service is not in force are of such a description as may be prescribed;
(b) such repairs or replacements have been carried out personally by the holder of a pilot's licence granted or rendered valid under this Order who is the owner or operator of the aircraft;
(c) the person carrying out the repairs or replacements shall keep in the aircraft log book kept in respect of the aircraft under article 22 a record which identifies the repairs or replacement and shall sign and date the entries; and
(d) any equipment or parts used in carrying out such repairs or replacements shall be of a type approved by EASA or the CAA either generally or in relation to a class of aircraft or one particular aircraft.