Both packs start working simultaneously if their buttons already in and you switch the bleed on. No harm to ears.

There is no FCOM limitation nor internal airline SOP that I am aware of, against pushing both batteries or both anti-ice switches at once.

It was definitely taught on our maintenance course to hit one switch at a time and wait for the response. Good airmanship etc.

I'm talking about after takeoff with packs OFF.

I’m also in the one button at a time camp.

A little like jumping in your car on a cold day and immediately setting off - nothing says not to, but a little “sympathy for the machine” can’t hurt!

Engine anti ice switches deal with different engines and have no connection with each other. Wing anti ice has only one switch. But both batteries are part of the same system.

Long gone are the days of 'sim' start in The Lightning.
Gang bar up for 16 switches, followed by double button push for engine start.
But then that operation was designed for.

Civil aircraft may not have the design requirement, but certification testing normally identifies any suspect systems, which by convention (now requirement) are changed to protect them from errant human activity vice relying on the human 'not to do something'.

Even pushing one has caused serious problem. In Australia one A320 or 319 when descending to 3000ft from 7000ft passing 5000ft they were cleared for approach. Pilot stabbed EXPED instead of APP then trying to press EXPED again to cancel it (that doesn't cancel EXPED) this time he stabbed ATHR causing THR LK which he disconnected using ID button which increased thrust to climb, then he disconnected AP causing 38kt flap overspeed. Pressing any switch is see, identify and do action. Any memory Muscle or otherwise or habit should play no part in it. Incidentally both PF and PNF were check pilots.

Ahh.. The five finger stab.

With most switches on Airbus or Boeing looking the same, as a trainer, I always advised to push one at a time though it may take 1 or 2 seconds longer any mistake or error could be reversed. And of course, it is a good idea to check you are at the right place, not the ones nearby. Too many times I have seen the stab effect leading to the packs coming off, fuel pumps off, anti ice on at 25C etc or in the case of one A330 I flew which had been “Boeingised” by reversing the switch direction, lights off when cleared to depart and on passing 10k in the climb.

A lesson well learnt when flying the C130 with its complex fuel system: the FE would point at the fuel source, follow to where it was needed and then push the buttons. Never saw a mistake.

Me

Lear requires both batteries on at the same time. Also has identical switches with near identical names for completely opposite action. (Emer Press and Emer Depress)

IMVHO the long slow poke one at a time is just good airmanship (airpersonship?) on any type.

The type of pilot that stabs quickly at buttons is also the type of pilot who doesn’t check the relevant system responds as requested. Thinking of the stages of error trapping, (Avoid, trap, mitigate), the button stabber will almost certainly be operating at the lowest level, mitigate. They’ll need ECAM / EICAS to tell them there’s a problem or will notice an issue after a period of time. The long slow poke followed by checking things are as expected (eg 1st pack on after t/o, feel the air volume entering the flight deck increase, then second pack on, same again) allows the person to operate at “trap” continuously and “avoid” if the slower actions prevent a mis selection.

The crew that is operating at the higher end of error trapping is also operating at the higher level of Situational Awareness. The levels of SA are Notice, Understand, Think Ahead (NUTA). If you correlate SA to error trapping, NOTICE = MITIGATE. UNDERSTAND = TRAP. THINK AHEAD = AVOID.

The crews who slow down and make singular selections are more likely to be operating at avoid/think ahead level which reduces their workload, avoids errors and allows them to maintain good SA, a positive feedback loop. They’re the crews most likely to have a calm, unrushed sector with a positive outcome (sim and flight).

The crews that make multiple rushed selections are more likely to make mistakes, forcing them to mitigate, upping their workload, causing them to rush, make more mistakes, mitigate again etc. a negative feedback loop. This is the crew that a sim check unravels quickly or has an incident on the line.

A calm, deliberate single selection at a time is a far more desirable behaviour than quick jabbing at buttons.

All IMVHO.

LD

And on the 'bus - read the panel section on the side and then move across to the button needing the action .

"Fuel"
"Crossfeed"
"On"



@lockeddoor - it's "airperchildship" as "son" is gendered :). Though some say that "child" is ageist, I haven't gone that far yet.
/s

Technically there is probably nothing wrong with pushing or not pushing those buttons at the same time. Humanly there is a lot to discuss... it’s the basis of why your lightning had a gang bar to start (military ops, 16 manipulations vs 1 under strong time pressure), and ie the 737 only to activate lights. Years ago there was a tv show on a certain Air Force with a pilot explaining his nickname: TOBI. Turn On Battery Idiot. Had to swap aircraft on quick react because it refused to start.

As we are not out on intercepts, let’s train them to go consciously step by step so they don’t get lost when systems don’t react as we expect them to? Let’s walk.

Ah... Makes sense then. Never did it in my life (Packs off take off that is), so this didn't come to my mind 🙃

But that was that just an instructor’s ‘ism’ that they themself picked up from being an engineer on the Herc in the ‘60s?

There are no technical issues with two switches at once - they're either hardwired to their respective system or the switch positions of the whole panel are polled and sent out over a data bus.

It is, in my opinion, unprofessional. Much like some crews who seem to pride themselves on running through ECAM as quickly as possible instead of sitting on their hands for a bit, pushing the button and making sure it does what you expected is just common sense. Fuel pump / battery / anti-ice / pack... it doesn't matter. Taking just a second or two to think through what you're about to do instead of relying on instinct is the way forward.

As a very new co-pilot on A320, I was a little too enthusiastic in my first non-normal in the FFS. "GEN 1... OFF THEN ON". Reached up and jabbed the button. A lot of relays and contactors clunking, followed by a silence broken only by the trainer wetting himself with laughter taught me a valuable lesson.

You can use the BAT switches for an interesting lesson in itself. My students would hit one, then observe that one switch was dark while the other had a message lit up. This of course led them to think that they needed to then push the dark switch, which switched that particular battery OFF again. It would lead to a quick recap of the dark cockpit concept (and the 'read the instructions' bit... the lit up message clearly states 'OFF').

We use a touchscreen based procedure trainer that only accepts one input at a time anyway at the touchscreens are not multi-touch :cool:

Modern systems are certainly not flawless and the old adage of ‘undo what you did last’ certainly still applies.
You can generate all sorts of transient gremlins in an electrical system when mashing buttons.
In pneumatic, fuel and hydraulic systems you can have valves that move slow or are briefly stuck while flow starts or pressure builds.
Theres no purpose in trying to turn everything on in 0.3 seconds.