fonawah

I have noticed on some flightdeck videos I have watched, during the TO roll, PNF calls "eighty knots"...In other videos the PNf calls "one hundred knots"
I was just wondering why the difference?
Is it something to do with the particular ac or the particular companies' SOP?
Many thanks

Engineer

As per SOPs at present call 80kts in other companies it was 100kts

BRAKES HOT

it's mainly an incapacitation call to make sure the other chap is still awake, and as a reminder that stopping the a/c is a more serious matter (ie only consider stopping for a serious problem after this point)

square leg

As said it's an incapacitation check.

The actual speed depends on the A/C type.

Some A/C nosewheels can be steered by the rudder pedals (+/-6°). The range becomes progressively less until full rudder effectiveness takes over (Vmcg).

Other A/C (smaller than 737/A320) mostly need to be steered by the handwheel and at some stage a hand transition is made from the steering column to the control yoke. Here it's an incapacitation check as well as a check to make sure that the yoke is being controlled by the PF.

Then it depends on whether the F/O or Capt is doing the take-off. Here it depends on comapny SOP's. Generally the Capt always has his right hand on the thrust levers and in case of rejecting the T/O will automatically have controls. Again, every company has it's style and has optimised its procedures.

fonawah

Thanks everyone for your answers

BlueEagle

On some aircraft some of the warning systems are inhibited after eighty knots until the nose wheel is off the ground, or, in other cases, until the aircraft passes 400'agl, therefore a master caution after eighty knots is possibly going to require an abort if the safety of the aircraft is in doubt, (engine failure, fire, system failure affecting the safety of the aircraft etc. etc. as per the usual take-off/abort brief).

A Comfy Chair

In the company I work for, it isn't used as an incapacitation check, as there is no response from the PF to the call... It is primarily used as an airspeed indication check.

IE If the PF isn't showing the called speed when it is called, something is wrong... standbys could be checked, etc.

Just another spin on it.

willfly380

firstly hi guys its my first day on pprune

it used to be 100kts for 2 reasons.namely for an incapacitation cross check and also to mark a speed above which a reject for a minor abnormallity was not recommended.
the last one still didnt work out as well so the speed has been reduced further to 80 kts .

Pegasus77

That's funny, in my company they're currently raising the calloutspeed from 80 to 100 :-)

willfly380

all airlines modify their procedure according to their own experiences. for example we have a lot of rejects due to door annunciator,we know a 737 door is pretty well designed so it wont be unsafe to continue the t/o ,but legally that cant be said so i believe in consent with the authorities these procedures are modified.namely the speed callout at 80 in place of 100.and ofcourse it serves as a speed cross check . earlier the better

keithl

I think the 80kt call has served various purposes - it has quite a long history. I believe (and I'm really at the edge of my memory-envelope here) in early military use (1950s?) there was a white line painted across the runway for aircraft to use as an acceleration check. If "80kts" hadn't been called by the time you reached the line you aborted - or, as we now say, rejected.

Engineer

Here was 80kts on DC10 same on 727 but 4 some reason company i worked 4 changed 2 100 But 80 now falls in line with sop 2 give 80kts call 2 deselect thrust reverse on ldg roll

I am just bsd but proud of it