Step climb departure best practices

[Mikehotel152]

I don't have access to the jeppy or aerad plate for the Compton 5X but can view the AIP.

In common with the WATFO and HEN altitude restictions, the specific altitude at the D18 boundary is a not-above, not-below restriction. Together with the notes on the plate warning of a step climb, I would certainly set 3000 on the MCP and not climb above unless specifically cleared by ATC. I would also have the 4000 and 5000 restrictons in the FMC to prevent level busts later in the SID.

Compare and contrast with a Clacton 8R from Stansted where the CLN D28 3000 altitude on the AIP is a not-below restriction whereas those at D21,16 & 13 are shown as not-above, not-below. I would therefore set 4000 on the MCP for departure, have it and the subsequent 5000 and 6000 restictions as hard altitudes in the FMC. Doing so, I have never had a word from ATC. It goes without saying that climb performance is not an issue and therefore being above 3000' at D28 is not a problem, but I would stop at 4000' unless cleared above.

It is therefore my understanding that a step-climb with the above type of restrictions does not allow a continuous climb to the highest altitude on the SID. The airspace around London is a bit complicated, with three major airports and plenty of GA traffic, so I can understand ATC's concern.