Calculating SGR

[flying67]

Hey everyone, I'm studying for the CASA atpl performance & loading exam and cant seem to get this SGR calculation correct. Would someone be able to confirm if i'm using the wrong fuel flow/GS?

Determine SGR with the following
- EMZW 78t
- ISA dev +5 degrees
- Wind -15kts (HW)
- FL: FL330
- Mach 0.79

The correct answer is 10.13.

I've calculated TAS as 465kts or using the B727 blue book I get 459kts. Then calculating for GS which is just minus 15kts.
Either 450kts or 444kts.
The fuel flow I calculated is (1490*3*1.2) = 5364kg/hr
SGR = 11.9 or 12.1

So still off. Is anyone able to help? Thanks

[Capn Bloggs]

I agree with your TAS (464 off my prayer wheel) and GS. Where is the source for your fuel flows?

[lucille]

“The fuel flow I calculated is (1490*3*1.2) = 5364kg/hr”

Whats the 1.2?

Coincidentally, 10.13 x 1.2 is pretty close to 12.1. …. Just sayin’

[flying67]

The fuel flow I calculated based off the B727 Performance and Operating Handbook - the one for CASA exams. I realised my mistake after and was meant to multiply by 1.02 for the temp deviation, not 1.2.