Airbus guarded switches colour
 

Hi,

Does anybody know why some guarded switches on the Airbus or red while others are black? A possible reference would be appreciated!

Thanks!

The red ones provide for non-reversible actions.

I just made that up, yet strongly believe that it the case. No reference :)

Red- Action on this switch is irreversible.
Black- Action on this switch is reversible.

:ok:

Thats what me and my colleague came up with as well...

However on the 380 the AC ESS override is guarded red but reversible...
Equally you can stop fuel jettison, so even though close it's not conclusive...

Appreciate the input!

for the A320, FCTM OP 040 ECAM HANDLING:

"in general, all guarded switches must be xchecked by pf & pm (except on grd) to prevent the flight crew from performing irreversible actions"

however, they don't say anything about the colours.

i will tend to agree with emach: Red- Action on this switch is irreversible. Black- Action on this switch is reversible.

True...but you can't get the fuel back.

I was just going to say that.

"Red" is required by regulation for emergency controls, i.e., controls used only for emergency procedures. see 25.1555

For what it's worth, the FCTM for the A350 sheds a little light on the Airbus Guarded Switch philosophy:

"...The flight crew must crosscheck the above-listed controls, in order to prevent any inadvertent action by the flight crew with irreversible effects (i.e. when the flight crew operates red guarded controls). If the flight crew inadvertently operates a black guarded control, the subsequent effect is reversible."

This is from A350 FCTM, AOP-30, "HANDLING OF COCKPIT CONTROLS".

Effectively, on the A350 anyway, the red guarded switched are irreversible, black guarded are reversible.

This obviously isn't necessarily applicable to all airbus aircraft, but it certainly gives some insight into the general Guarded Switch philosophy, and does appear to hold up for the A330.

I was told during ground school that the black guarded switches are more related with maintenance action whereas the red ones are to be controlled during flight in abnormal and emergencies.

Red can't be reversed, such as RAT deployment. Black, you need to be sure of such as MAN engine start or EVAC command.

It now holds for all Airbuses A320 including

I was told that the Eng and APU Fire Pbs were reversible. They are in the sim - without a "Systems Reset". There is nothing to that effect in the FCOM (unless you know differently) and one would have to be in a lot of trouble to even consider relighting a damaged engine.
Does anyone have any information which might confirm or contradict this assertion?

Hi mcdhu,

I can't find the official incident report of BA 9 24 June 1982 but from memory and confirmed by wikipedia, No 4 engine failed first and the Fire Engine Checklist was completed as far as pulling the FCH and arming the bottles. After the remaining 3 engines had also failed (I guess that would count as "one would have to be in a lot of trouble to even consider relighting a damaged engine"), the first engine to be relit was No 4. Fortunately Flt Engineer Barry Townley-Freeman re-stowed the FCH (not in the QRH relight procedure) - so well done Barry.

We have one A320 which has a High Altitude Landing pb and it has a Red guard.Obviously the switch has a reversible action.It reschedules the altitude at which Pax 02 deploys

I'd guess when you switch it OFF when in High Altitude envelope, you get 'rubber jungle' in the cabin. So it is kinda irreversible...

On the A330 there are 2 red guarded switches that are reverseable.
Ditching PB and the AC essential feed PB.

Black guarded switches are reversible, red ones are not.

Reference is from the latest FCTM 22 march 2017.

Red - Once pressed can be re-set only on ground !
Black - Once pressed can be re-set on air and some used for maintenance.

Ditching pb is black on the A320.

The reversible-non reversible philosophy seems to be valid for the A320