Incorrect STAND ALERT lamp logic/circuit ?

[Ramsay]

I found myself diving on a target in the L-39ZA with the 'STAND ALERT' lamp lit and unable to fire because I had forgotten a switch (the pedestal 'Launch' C/B).

 

From what I can make out from the real manuals, the 'STAND ALERT' lamp is part of a 'Tally' system and confirms/warns the pilot that the selected weapon is ready to fire and ALL switches are correct (except for the Trigger 'Safety' flip switch).

 

Currently in 1.5.3 the L-39C and L-39ZA "STAND ALERT" lamp will light if

 

• 
  
• "ARMS" C/B ON position and
  
• speed is above 310 ± 15 km/h
  

even if the weapon switches are incorrect/off or the air to air missile station empty.

 

AFAIK

 

In Air to Air mode the "STAND ALERT" lamp should go out, once a A/A missile is fired until the selector is switched to the other station.

 

 

In the ZA the "STAND ALERT" lamp will only light after the "LAUNCH" C/B on the centre pedestal has been armed.

 

It is hard to tell from the descriptions which/if any other L-39ZA switches (Heating, Glowing, Rockets, Bombs, Gun-GS, etc.) block the "STAND ALERT" lamp as the arming procedures called for them to be ON before the "LAUNCH" C/B (called the "FIRE" switch in the above text).

 

NOTE: The above description suggests the rear "ARMS" C/B disables the weapons but allows the "Tally" system "STAND ALERT" to work for training purposes - currently the rear "ARMS" C/B removes power from the weapons and the "Tally" system.

 

The L-39C manual (T.O. 1T-39C has known errors) does mention the UB-16 C/B as a requisite

 

Rockets

• When "ARMS"

• and "UB-16" C/Bs are in ON position,

• rockets firing mode selector in one of the operating positions

• the speed is above 310 ± 15 km/h

- the "STAND ALERT" advisory light on the fwd cockpit upper armament indication panel and on the aft cockpit left armament indication panel comes on.

It's quite possible the Nigerian L-39ZA's the English manual (has translation errors) was written for differ from the one modelled in DCS, but seems strange there is so little feedback to confirm the ready state of the weapons system.

 

EDIT:

I'll add that in 1.5.3 the "STAND ALERT" lamp stays lit above 310 ± 15 km/h - even when the pitot system is damaged and the airspeed indicator reads zero (I don't think separate left/right pitot damage modelling is in yet).

 

The pitot schematic on page 128 of DCS_L-39_Flight_Manual_EN.pdf shows the pressure switches/sensors for the weapons, landing gear, etc. that should be affected.

Edited February 29, 2016 by Ramsay
Stand Alert also stays lit when Air Speed Indicator read zero due to pitot damage