have you any idea why the Canberra RW35 procedure we're talking about directs a track of 353M until 5000 AMSL when the 25nm MSA is 4600AMSL?
Yes. See YSCB Noise Abatement Procedures page 4, link given in previous post.
4600' is for terrain clearance.
5000' is for noise abatement.
If I was departing YSCB using the RW35 OCTG I could turn at 4600'
If you were in a Baron or a Titan, yes.
If you were in a >5700kg aeroplane like a Metro 23 - No. The Noise Abatement requirement is more restrictive than the terrain clearance.
It might be on a different AIP page, but the AIP assumes that pilots can read and understand English, and will take the trouble to follow links and directions, even if they are on another page!
If you are not yet flying >5700kg, you might not be briefed on noise abatement procedures or the principles behind them.
(or as low as 4600-965=3635' to ensure 35' terrain clearance) if I desired.
Victor, you are scaring me!
Your reference to 35' suggests that you are familiar with, and probably operating your aeroplane to
CA0 20.7.1B
If that is the case, perhaps you should take a very close look at that CAO before you start making ad-hoc decisions to clear obstacles by 35'.
Paragraphs 12.1 and 12A are normally satisfied by an operator drawing up Regulated Takeoff Weight charts and Escape Procedures (engine-out SIDs). A job that poses a challenge to a trained performance engineer!
Starts to get a bit tricky having this discussion on a bulletin board, and maybe I misunderstood your remark, but I would be planning to achieve an MSA or LSALT 'minus nothing', not -500' or -965'.