All,Got a aft cargo fire little while ago in the 744F. The aft cargo fire bottle armed, and the plastic guard comes off the discharge button. But when the button is pushed, the bottle doesn't discharge. Known bug or "feature?"Thx

Does anyone from PMDG read this forum?

Yes, they do. And one of the guidelines of this forum is to sign your post with your real name. Since I have never used them, makes me wonder if they have modeled that system to do so. But that is just gueeing on my part.

The bottles wont discharge if no fire is detected

The fire was detected, why do you think I was trying to put it out?I'll wait here for the forum police. Dan be a good chap and let them know I'm the guy wearing the Carmen Miranda banana hat?

Well I´ve tested the cargo fire fighting system and it works fine with me. Both fwd and aft cargo fire suppression works.But you have to be patient, it takes some time to extingush a cargo fire( all four bottles will provide a total of 195 min fire suppresion!). Fwd cargo took about 5 min and aft cargo took a while longer and even needed bottles C and D ( I got an eicas message saying that bottles A and B have been discharged)!So you see the system works fine. If it doesn´t on your system, its a bug or something.

I was at altitude when the bottle wouldnt discharge. I just tried it on the ground and the bottles fired fine, and I got the discharge light on the button along with the EICAS message. I'll try the inflight again.

There's no need for forum police, but it's certainly a snappy and disrespectful retort to reply to someone that way, all the while continuing to ignore our forum rules.Please edit your signature to include your real name, or at least submit it in your posts, as per our wishes.Thanks.

"The bottles wont discharge if no fire is detected"Where does it say this, Paul?All my manuals indicate otherwise.Cheers.Quincy>

Q,Actually nowhere, forget what I said...However, the point is that theres no gauge indicating that cargo fire bottles are discharging. The only clue you will get is either the EICAS message >CGO BTL DISCH after approx 30 min wich means bottles A and B are done or the fire warning stopping wich means the fire has been supressed. And it takes some time to either supress the fire or to empty bottles A and B. And my guess (its really only a guess I dont want to be offensive to anyone) is that our still nameless guy was a bit impatient and expected to have the fire supressed within seconds wich of course didnt happen and he suspected a bug or something like that.

I'm not sure if the original poster was talking about the DISCH light or the CGO BTL LOW EICAS indications.The DISCH light on the cargo fire panel is triggered by a 25psi pressure in the line from Bottles A and B (pressure in the discharge line is normally cabin pressure prior to discharge). Since there is 360 psi in the bottles, one would assume that the DISCH light would illuminate immediately. The DISCH light is kept illuminated after the pressure in the line has decayed below 25psi by "less-than-300psi" pressure switches on the bottles themselves.Bottle A and B lines are large diameter, so the bottles will discharge relatively quickly... I don't think we are talking minutes here, but one big blast in seconds. My notes are a little vague in this area, however.If the fire reignites prior to 30 minutes elapsing, I think you'll be in big trouble. Cheers.Q>

ur mayb right but it took about 6 min for my fwd cargo fire warning to go out