777 QRH Vref

[blah blah blah]

Hi all,

Im going mad trying to find either tables or graphs that give Vref. Ive hunted through the QRH, FCTM, FCOM to no avail.

The best I can find are 5000' holding speeds that are based on Vref+20 etc such that I can work backwards to find the Vref for a weight. This process is clearly a bit gash.

There must be a way to work out Vref following a FMC and EFB failure?

Any help greatly appreciated!!

Blah

[Ex Douglas Driver]

FCOM2 - LANDING - LANDING PERFORMANCE - VREF Chart

[blah blah blah]

Found it! Naturally it was right in front of me the whole time...

Thanks for the pointer!!

[haejangkuk]

Im going mad trying to find either tables or graphs that give Vref. Ive hunted through the QRH, FCTM, FCOM to no avail.

The best I can find are 5000' holding speeds that are based on Vref+20 etc such that I can work backwards to find the Vref for a weight. This process is clearly a bit gash.



You really scare me...exactly like some of our NTR DECs at KAL!

[blah blah blah]

You really scare me...exactly like some of our NTR DECs at KAL!

Why?

Because Im new on type?
Because Im new to the company and these manuals?
Because I tried to find the answer to something that wasn't covered during training?

pprune is a fantastic resource thanks to the incredible amount of knowledge that is held amongst the members. pprune is however let down by the whingers, the moaners, the people that can't just give a reasonable answer to a reasonable question.

[Poire]

I use a trick since my 727 days to roughly find the Vref:
Gross weight divided by 3 then add 70 or 65 (200/300 and 300ER, respectively).
It gives you a very good approximation.

[blah blah blah]

Cheers for that Poire,

Ive just tried your rule of thumb. The 200ER comes out within 1kt, the 300ER is within 2kt. Interestingly the QRH figures come out on the low side for the 200ER but high for the 300ER.

A great ballpark start when all the electrics go down anyway!

Cheers

Blah

[8che]

Do you not have a paper QRH on board as back up ? You should.

[blah blah blah]

Yep, we have a paper QRH, hence the original question about trying to find the figures when the FMC and EFB fail.

Even so, its always good to have a trick up your sleeve such as the above rule of thumb. Anyone else have a good trick for the 777?

[Stuart Sutcliffe]

Gross weight divided by 3 then add 70 or 65 (200/300 and 300ER, respectively).
For the benefit of clarity all round, would that weight be in pounds or kiligrams?

[Virtual Reality]

I am sure it is in 'kg'. Landed this afternoon on -300 with 220T ldg wt, vref30 was 143 kts, which was spot on ......:D

Thanks Poire.......:ok:


VR :cool:

[Poire]

Sorry fellows, that will be kilograms

[dv8]

I use this rule of thumb
Vref30=(ATOW/3)+69RR +65GE

or

QRH >Performance Inflight >General >Vref