Northolt CPT5X SID
 

Hi,

This SID has quite a large climb gradient required to 3000 feet (13%)
There is a note in the jepessen chart that says something along these lines:
Aircraft unable to comply with the SID contact ATC prior to departure.

My question is this: What do you do if you know with all engines operating you can comply but with an engine out you can't?
Do you need to assume the engine failure case and therefore reduce your weight(This option is the safest one)
If this is impractical and you contact ATC to let them know you are unable to comply, will ATC give you alternate departure instructions while taking off in 07?

I would appreciate an answer from a controler that knows about this particular case.

Thank you,

JAG

JAG,

It's nice that someone actually reads their plates... the number of pilots that don't say anything and don't make the altitude is a worry. All the airway SID's from 07 should have that warning.

All airways departures from Northolt are transferred by Tower direct to the Outbound TC controller, but the bit in between 2400 feet and the runway is airspace that is controlled by the Northolt Radar controllers. So to reduce pilot workload of having to keep swapping frequencies, the departures controller will procedurally release aircraft.

So if you can't make 3000' by the London Control Zone Boundary (thus remaining within the protection of CAS), the departures controller will (as part of the release approval) instruct tower to keep you on their frequency until passing 2400 feet (so you’re back inside CAS), whilst radar monitoring your flight.

This release approval will be given subject to the departure controller ensuring that all aircraft outside CAS will be at least 5nm away from your flight. So effectively you will be receiving a Deconfliction Service until you’re established inside CAS.

I hope that this makes sense.

Regards

MM

I know you wanted a controller's opinion but I think you'll find that the majority of published minimum climb gradients are for airspace, noise and other such reasons but not terrain considerations. The published gradients are for all engines operating and if you can't make these gradients you will have to reduce your TOW. But all bets are off N-1 when you should follow your aircraft's T/L tables. Although 13% is significantly greater than a normal SID, most modern twins should be achieve this to 3,000'.

PM