Jump to content

Sign in to follow this  

747-400 Vref question (30 Ref)

Recommended Posts

Greetings all,I've been reading the flight sim version of Tolstoy's "War and Peace", aka: the PMDG 747-400x manual. A LOT of reading. I have a question about V speeds. I'm pretty familiar with V1, V2, and Vref, but I'm not sure about something called "30ref". In the climb modes section, it indicates you should climb at "30ref +100" What exactly does the "30" signify? Obviously, I should be climbing at 100kts plus whatever "30ref" is, but I'm stumped as to what that is. Thanks for your help.Ron

Ron Priever


Share this post

Link to post

Hi Ron,REF 30 and REF 25 are landing speeds depending on what flap setting you choose,these can be found on the APPROACH REF Page on the FMC. Flap 25 is normaly used unless your landing near Max weight but it all depends on what airline you fly with. you would also make adjustments for wind additives eg add half the headwind speed to your landing speed. so if the runway is 360 degrees and the wind is 360/16 your speed would be VREF + 8 knots.On Departure You should use the following speeds. However if your flying under VNAV the Aircaft does the hard work for you :)Flaps up you should maintain VREF 30 + 100 knotsFlaps 1 VREF 30 + 60 knotsFlaps 5 VREF 30 + 40 knots Flaps 10 VREF 30 + 20 knots ( Light Departure)Flaps 20 VREF 30 + 10 knots ( Heavy Normal ops) Flaps 25 VREF 25 (Landing speed in FMC)Flaps 30 VREF 30 (Landing speed in FMC)Rob

Rob Prest


Share this post

Link to post

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
Sign in to follow this  
  • Tom Allensworth,
    Founder of AVSIM Online

  • Flight Simulation's Premier Resource!

    AVSIM is a free service to the flight simulation community. AVSIM is staffed completely by volunteers and all funds donated to AVSIM go directly back to supporting the community. Your donation here helps to pay our bandwidth costs, emergency funding, and other general costs that crop up from time to time. Thank you for your support!

    Click here for more information and to see all donations year to date.
  • Donation Goals

    AVSIM's 2020 Fundraising Goal

    Donate to our annual general fundraising goal. This donation keeps our doors open and providing you service 24 x 7 x 365. Your donation here helps to pay our bandwidth costs, emergency funding, and other general costs that crop up from time to time. We reset this goal every new year for the following year's goal.

    $540.00 of $25,000.00 Donate Now
  • Create New...