The Annual Inspection is all about making sure the aircraft is in an airworthy state. It is carried out by CAA licenced aircraft engineers; in our case Ian Surley and Barry Lytollis. Typically the work can be split in 3 categories:
a) Regular work. A thorough inspection of all parts of the aircraft in accordance with the Self Declared Maintenance Program (SDMP) which has written specifically for each aircraft. This includes cleaning most of the aircraft and lubrication of moving parts as appropriate.
b) Known Issues. Rectification of items of which have arisen in the past but were not deemed sufficiently serious to require immediate attention. We can plan for this activity and obtain spares in advance. We have a reasonable feel for what is involved in this but there can be unexpected difficulties arising.
c) Unknown Issues. Rectification of items which show up as part of the inspection work and are deemed to require attention before the aircraft can fly again. This can include more detailed inspection work and obtaining or making replacement parts.
We have had all three categories to deal with on this Annual Inspection and it is the Unknown Issues which has caused delays this time around.
Typically the Regular Work takes a day or two to complete.
This year the Known Issues on the Alliance were:
- Replacement of the rudder cables as we considered the crimps to be of unknown quality.
- Replacement of the tail wheel tube and tyre.
- Replacement of the two stick gaiters
- Replacement of the radio loudspeaker
- Investigation and adjustment of the airbrake locking force required
Of these, the rudder cables were thought to be the most likely to take more time than expected as they involve access to awkward parts of the aircraft and there is the potential to require more dismantling than expected. Experience of a similar exercise on the K21 last year has taught us to expect the unexpected!
In the event the cables themselves were not too problematic, but upon removing the rudder to fit them, it became clear that the hinge bushes on which the rudder moves had become so worn they needed replacement (the first of the Unknown Issues). Fortunately Barry was able to machine some new bushes using his lathe at home but this took several iterations to get them perfect. See pictures. Delay number 1.
Tim Fox
