Question on fuel indicator: Su-27 & Su-25T

[DarkFire]

I understand that the fuel indicator on the Su-27 and Su-25T indicates volume of internal fuel in 10s of %. My question is what the small yellow lights to the left of the gauge mean? Are they indicators for individual internal tanks being empty?

 

A second question in relation to the Su-25T (and I guess the Su-25): is there an indicator that shows when the external tanks are empty?

[ShuRugal]

The fuel level is indicated in metric tons. The yellow lights are indeed to indicate empty tanks. don't know about a light for externals, i never bother with them on the 25

[Ironhand]

...

 

A second question in relation to the Su-25T (and I guess the Su-25): is there an indicator that shows when the external tanks are empty?

Yup. Both the fuel quantity indicator (Su-25T) reflects the extra fuel and the empty tank lights are illuminated when they're empty.

[DarkFire]

Ah thanks, so the total fuel shown on the gauge includes any fuel stored in external tanks. Makes sense.

 

I don't usually use externals on the -25T but I'm practising a medium to long range SEAD mission against higher-end SAM sites for which I've found the best approach is a terrain-following trip through the mountains (around 80km in total) followed by a pop-up attack from ~25Km range. Doing this sort of approach to the IP sucks up a LOT of fuel. First time I tried it I ended up having to divert on RTB due to lack of sufficient fuel to make it back across the mountains, even at high (for the -25 anyway) altitude. Hence the externals.

 

The Su-25 / -25T can also be a real pig to fly through narrow valleys at max weight. Makes for some interesting edge-of-envelope flight training :joystick:

[Ironhand]

Ah thanks, so the total fuel shown on the gauge includes any fuel stored in external tanks. Makes sense.

 

I don't usually use externals on the -25T but I'm practising a medium to long range SEAD mission against higher-end SAM sites for which I've found the best approach is a terrain-following trip through the mountains (around 80km in total) followed by a pop-up attack from ~25Km range. Doing this sort of approach to the IP sucks up a LOT of fuel. First time I tried it I ended up having to divert on RTB due to lack of sufficient fuel to make it back across the mountains, even at high (for the -25 anyway) altitude. Hence the externals.

 

The Su-25 / -25T can also be a real pig to fly through narrow valleys at max weight. Makes for some interesting edge-of-envelope flight training :joystick:

SEAD with an Su-25T loaded to the gills? There's an adventure for you. :)