I have the above and ATC report my mode C is at best intermittent or none existent. Please can any one offer advice on possible cause? Can the Mode C be activated or deactivated by a switch?
Thankyou
Sure. Pressing ON selects mode A only, pressing ALT selects mode A plus mode C. Mode S is active either way.
The cause will most likely be a discrete altitude encoder. They’re relatively cheap and not normally repaired.
