G7USL

Positive Rate

Recommended Posts

What are the requirements criteria for the call 'Positive Rate'?

Share this post


Link to post
Share on other sites
Help AVSIM continue to serve you!
Please donate today!

On most airlines, it is typically that the PNF makes that callout when there are two indications of a climb, these being the VSI and the altimeter. It differs on Boeings to Airbuses, one SOP says use the phrase 'positive rate', the other says use 'positive climb', but personally I sing this instead, as it is far more fun lol: https://en.wikipedia.org/wiki/The_U.S._Air_Force_(song)

Since it is the PNF that makes the call, that's kind of ironic, because if the PNF is in the right seat, it's actually the altimeter on the left seat instruments which sends the transponder altitude data to ATC scopes lol.

But really, one should not rely too much on the VSI's reading, since it gives pretty much an 'instantaneous' reading of what the aircraft is doing, thus it can potentially indicate you are climbing when you might simply have hit a minor bit of turbulence or bump on the runway which bumped you up off the runway for a second or so; you could still then settle back down onto the runway (same with the radar altimeter as well, especially since the sensor for th RA is right at the rear of the aircraft, where it will be affected by being far from the pivot point of the main gear and would actually show a descent when you rotated lol).

The altimeter is a far better indicator for a true positive rate of climb, because it works off air pressure from the static port, so it has a bit of lag in displaying a climb, which means if you see your altimeter needle indicating a decent climb, you really are going up at a positive rate.

So long as you are nowhere near Vle (maximum gear down speed), then there is no rush to give the callout (personally, I'd say give it at least 100-150 feet altimeter indication before making the call; it's better to be safe than sorry by trying to be cool and get the gear up the moment you lift off, because if you settle back onto the runway with the downlocks off, your career as an airline pilot is probably going to be over.

In other words, the reading on the VSI might say you are going up, but the needle on the altimeter actually means you are going up!

 

  • Upvote 1

Share this post


Link to post
Share on other sites

There is no formal requirement except good sense.

DJ

  • Upvote 1

Share this post


Link to post
Share on other sites

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