Rigga
What are you smoking?
Firstly chinnook wheels are always extended! so what do you mean the proximty switchs lock them fore and aft??-they are fixed mate. I think what you meant to say was the aft gear can be locked or in swivel or steer.
A Chinnook does have a ground contact switch on the aft gear which illuminates a ground contact light on the panel also these switchs drive the LCT's to ground position and it also removes 50% authorithy in fore aft cyclic through the AFIC's.
Not sure what's Rigga's on about but he got one thing right- it certainly was simple