Positive Rate/Positive Climb?
 

Could somebody please explain why after Take-Off in the Boeing FCTM the PM calls Positive Rate where as in the Airbus FCTM the PNF calls Positive Climb.

Apparently it's to do with where their get their information from. i.e. one determines it from the VSI and the IRS where as the other determines it from the Altimeter and the ADIRU which in the manufacturer's eyes determines the climb away.

Any substantive info would be welcome.

I think it's only manufacture/company fancy and it's only callout.
Pilots should confirm that they are really climbing by looking on VSI and altimeter, then call sth appropriate to PF (according to SOP).

FWIW my Boeing FCTM does refer to confirming positive rate of climb as part of the takeoff procedure but the standard callout, as detailed in the FCOM Part 1, is "positive climb".

The same callout, "positive climb", also applied on my previous Boeing type so I suspect you've been misinformed.

It changes every 10 years anyway..don't worry!

positive climb is one where in 02 separate instrument inputs advise that u r climbing.
Conventional (without RA) os VSI and ALti
With advanced
RA is one and VSI is the other..

I suppose with the IVSI, one could use RA/IVSI/Alt..
and the call out could reflect which is the Second one one looks at..
Just my tupenny bit..

Positive rate or positive climb calls after take-off.
 

Make sure that you do have a positive rate before selecting the undercarriage up. The VSI is not as good as the IVSI in giving you this information.

In the company I work for, the Pilot Monitoring (PM) calls 'positive rate'
when a positive climb is indicated on his / her Altimeter. B757 B767

I suppose it is all a question of Company history.

I rather strongly suspect that's all there is to this.

It's been "positive climb" in my lot on all the large Boeings for over 20 years, irrespective of whether it's triple INS, triple IRS, ADIRU, VSI or IVSI, etc etc........

Positive Rate- Source-VSI
Positive Climb - Source- RA or altimeter.

Nor a big issue in a medium , but a big one in a heavy. Very often you have positive rate just after rotating the nose wheel , but the MLG is still running.

Better to check the climb.

In my previous (EU legacy carrier) we said "positive climb" even though we flew mainly mediums, in my current (major SE Asian carrier) we say "positive rate" even though we operate widebodies exclusively... so yes, company history I suspect.

"positive rate" = VSI says we go up.
"positive climb" = we ARE going up!

I was told it's because the VSI (being driven from the IRS) will give a positive rate of climb during rotation. Not a good time to select the wheels up so multiple sources used to confirm a climb (rad alt etc).

FWIW

From a current Boeing Ops Manual/FCOM

P2... "Cross checks flight instruments and when radio height is increasing calls "Positive climb"

I suspect ;) some of us are "sweating the small stuff" here, since rule one, common to us all, is: "don't crash"....the exact answer as to procedure and terminology is going to vary from company to company. IMHO the correct answer is do as your FCOM says, as your trainers teach and what your checkers check, regardless of whether it's a Boeing or an Airbus.

Positive rate, positive climb, Auto-throttles, Autothrust...Just one manufacturer trying to act like it's the innovator or something by not using the other's terms.

I think the RA increasing is pretty important as you can have a positive RoC on the VSI and still be on the ground when there's a significant upslope. THR comes to mind.

The combination of the two will stop you raising the gear when the ground falls away temporarily but you're not actually going up...

Boeing FCTM
 

"Retract the landing gear after a positive rate of climb is indicated on the Altimeter"


The Altimeter is the primary indication of a climb for Takeoff and Go-Around.


Altimeter requires a change in pressure to indicate a climb. There is some lag and will help to keep you safe in a windshear event.



The IVSI uses IRU/ADIRU and will indicate a climb with a pitch change, if you are not climbing it will return to zero. Some years ago Boeing removed VSI from the above requirement for a positive rate.


Rad Alt will indicate a climb if the terrain is falling away.


Why is there such a rush to get the gear up? I regularly see guys calling for gear up before the ground/flight relays open.

positive climb
 

I changed 3 companies flying Airbus all calling "positive climb"
Actually i find this call out a little bit strange as there would be no "negative" climb.
Arent i right?
Although i am so used to say positive climb , it makes much more sense to use "positive rate"
Different point of view :)

I just use my best elevator voice and say "going up":ok:

Wiggy, I suspect you have company ammendments. Our stndard FCOM1 says
.

"Why is there such a rush to get the gear up? I regularly see guys calling for gear up before the ground/flight relays open"

I suspect second stage climb?

I suspect it's because they're imagining how "cool" it looks to have the doors cycling, and the gear retracting, as they leave the ground. There'd Lso be a bit if good ole make machismo, "look at me, I can get it done quicker than you".

On the matter of positive rate v positive climb, I don't believe the intent or reference instruments are different. Just a different term.

Ive had one bloke tell me how the Rad Alt is his reference for positive rate. :ugh:

Capt Claret
And why does that make you bang your head? Seems reasonable to me.

Tyropicard
 

Because both Boeing and Airbus recommend something else - that why he is banging his head.

And the radalt may just show a positive increase during rotation (because the antenna are forward of the wing leading edge) with the mains still on the ground.

And, I've had enough people call "positive rate" with the altimeter indicating an altitude less than that at the start of the takeoff run, to know they're not really seeing any true indication that we're climbing.

Seriously?
You wanna think about this one again?:E

Nope. What do you think needs rethinking?

Read the airbus books again.....

-POSITIVE CLIMB..................ANNOUNCE
Announce positive climb, when the vertical speed indication is positive and the radio altitude has increased.

Any questions?

No mention in the manual of how to determine positive rate.

I still reckon if the altimeter shows a level lower than that at the start of the takeoff roll, one should not call "positive rate" yet.

when the cows on the field are getting smaller and smaller its a sure way to determine you are climbing i would say :ok:

I'd agree.

But when the call "gear up" or "positive rate" is made as the mains leave the ground, one can't always be sure that the cows will remain in sight. :ok: :eek:

I don't yet fly aircraft with retractable gear so please forgive the question, but what are the criteria which need to be met for the 'gear up' call? Is it just a case of "positive rate" from the pilot monitoring results in an automatic "gear up" call from the pilot flying, or is there more to it than that? Thanks, Rich

In theory, the PNF/PM observes two indications of climb, usually altimeter and VSI, and then calls "positive rate/climb". The PF confirms same, and calls "Gear Up".

exeng, Claret
Any actual thoughts on why RA is not a suitable reference for the call? airbus might be wrong...

G'day TP,

Until this conversation I'd not considered Rad Alt as a source, probably because for 20 odd years I've used VSI plus Altimeter, so I wouldn't be brave enough to suggest Airbus (no bus time personally) has it wrong.

However, much like an engine failure where two instruments should be used to identify the failed engine, I believe it unwise to rely on only one source for positive rate. I guess my main bone of contention, is being asked to retract the gear as the mains leave the ground with no thought of what might happen should the aircraft encounter a downdraught or for whatever reason not really be climbing away. Sort of like the occasional incidents of folks selecting gear up on the ground and relying on the squat switch to keep the gear from retracting (admittedly this is usually associated with light aircraft).

In the 717 FCOM, there's no explanation as to why Boeing recommends the PNF observe positive rate, call it, then the PF confirms same before calling for gear up. But were I a betting man, I'd reckon that at least one reason is to slow the process of gear retraction just a little, to ensure the aircraft is properly gaining altitude, and doesn't settle back onto the runway on its belly.

When you're up to your arse in crocodiles, you forget that you came to drain the swamp.

So stop creating crocodiles.

If you are climbing, it will be at a rate. It matters not what call you use (company sop of course).

Just make sure the gear is off the deck and the aircraft is going up!

"Positive climb" always makes me smile. A climb is always positive; otherwise, it would be a descent... unless you call that a "negative climb"!

So in my case, "positive rate" it is. And yes, that means increasing VSI, ALT, and IAS. Plus of course the houses getting smaller (if in VMC)...

But at the end of the day it's just one manufacturer trying to be clever...

Cheers :cool:

For me, positive rate makes me think of VSI, positive climb is the A/C flying away from the ground, checking all available sources, VSI,ALT, RA, houses getting smaller etc, some VSI, not dampenned by the IRS, can indicate a climb during the change of attitude at rotation. Calling positive climb seems to be indicating that I've checked the A/C is climbing for real!

If you're taking off from Courchevel's airport you are guaranteed to get a positive rate from the RA even if you're actually descending instead of climbing. This is an extreme example, but there are plenty of airports out there where the ground falls off rather sharply after the runway threshold, thus making RA readings irrelevant for the purpose of establishing whether the aircraft is actually climbing as opposed to the ground just dropping off more or less sharply.

Ciao,

Dg800