ppng
I believe you may be flying from the Ice Station? (as it's become known...) If so, I was on duty when you phoned your query in.
The answer is: In our Class D CTR/CTA below FL100 you are only
required to request clearance for a speed change
IF ATC has specified a speed for you to fly at and you are not less than 4 miles from touchdown when on an Instrument approach.
However, we do appreciate being told if you or anybody else are going to fly at speeds significantly different to "standard" operations - for example, a 332 reducing to 100kts or less without warning can be seriously embarrassing
So though it's not
required to request clearance to, in the interests of harmonious relations it's best to forewarn us that you are going to slow down (or speed up, if you have the capability - 225/76?)
Come across for a visit - we might even be able to locate some coffee.
DD