Hold at Cruise Definition

[BrassAPE]

If a fuel reserve policy includes 45 minutes hold at cruise altitude, at what mass and altitude is this calculated? Is it at:
i) the end of main mission cruise mass and altitude and min fuel flow speed;
ii) the mass just before or after the landing phase at the alternate and at the associated optimum cruise altitude for the min fuel flow;
iii) Something else.

CONTEXT: C-Series performance data uses this definition.

Many thanks

[+TSRA]

Hi BrassAPE,

As the C-Series is Canadian built, the original references from the Canadian Aviation Regulations will apply, save for any amendments required with any import certificate.

Fuel for transport category aircraft is referenced in CAR 602, CAR 705, and CASS 725. In short (and combined for clarity), it requires that reserve fuel is calculated for the aircraft to hold for 30 or 45 minutes (jet or turboprop respectively) at an altitude of 1,500 feet above the elevation of the alternate airport at the planned landing weight.

The difference between the Canadian requirement for a 30-minute jet holding time and the 45 minutes you outline may be a requirement of the import certificate (e.g. the UK requires 45-minutes for jets) or it may be nothing more than a carry-over/copy-paste error made by the tech editors. Either way, 45 minutes is better than 30!

For most other Bombardier products, there are specific holding fuel charts which outline the fuel burn and airspeed to fly during a hold. I would suspect the C-Series would be no different, and you can find these in the AOM Performance Volume.

[BrassAPE]

Thanks for your response +TRSA. I am familiar with the 30/45 min rules but at 1500ft but not at cruise altitude.

It seems to be a Bombardier thing. I saw it on some C-Series marketing material and have also seen it quoted explicitly on some unrelated Bombardier used aircraft sites (both Jet powered). As I lost my old login, I cannot share the links.