Alligning the IRS[Answered]

[rnurse.bc]

Hello,

Should the IRS be alligned before or after starting the engines? If after the engine start, the IRS takes so long that over 2000 pounds of fuel burns away, making that impractical. When is the official time to allign the IRS.

The manual seems to state After Electrical Startup, not After Engine Start.

The manual does also state to be careful when switching GEN from EXT to ON so that the IRS do not lose power. So, this probably means to shift the Generators from EXT to GEN On one at a time, so the IRS maintains power after engine start.

Please advise. Thanks

[Slayer]

Yes you should, as you have noted it would be a waste of fuel otherwise.

[rnurse.bc]

When do you allign the IRS when flying this airplane? Before starting?

[rnurse.bc]

Ok I just did a full allignment by using electrical power only. I established electrical power by connecting the GPU, turning on the Engine Master Switches, setting the GEN switches to EXT, and Signalling External Airflow Start.

I successfully alligned the INS, and am ready to start

Now the problem is when I try to start, I crank the left engine and the sound of the engine spooling is heard, but no increase in RPM is seen. So you are left hearing that spooling up sound of the engine, and the crank switch remains in Engine Right position. This never stops until I reset the airplane.

So like the manual says, I can only align the INS after start. Because this problem exists.

[JonathanBleeker]

What I would do is warm up on electrical power, not alignment. That's where most of the time is taken, waiting for the Heat light to go out in standby mode. It isn't going to cool down quickly while you start the right engine (start right first not left as that's the one that drives the bus the INS is on), and then you can switch to align while running only one engine and start the left whenever you wish. That way you don't waste as much fuel.

[rnurse.bc]

Please advise on the engine start issue I discussed above. I cannot run on electircal power for long. Advisors indicate that the INS must be alligned before engine start, and on electrical power.

[JonathanBleeker]

Please advise on the engine start issue I discussed above. I cannot run on electircal power for long. Advisors indicate that the INS must be alligned before engine start, and on electrical power.

You remembered to signal external airflow via the addons menu to that engine?

[rnurse.bc]

Yes. I leave this on since before the allignment procedure to cool the CNI.

[JonathanBleeker]

That's actually the command to signal airflow for a particular engine and has to be done for each engine before you move the start switch.

[rnurse.bc]

I'll describe the issue for you:

Before starting the engine I can turn on the master switches, install the GPU, and the set the Generator switches to EXT. That establishes electrical power to the aircraft. This is suppose to be for indefinate. To cool the system as the manual indicated, it is mandatory that you turn on External Airflow to cool the equipment.

No here is the problem. If you leave the aircraft int his state for too long, as malfunction happens. This is the state that is required for engine start. So I crank the right engine, you hear the spool up sound, but there is no increase in RPM for the right engine. This situation continues indefinately, as the crank switch remains in Right, the spool up sound reaches to the end and then starts over, and the engine RPM remains at zero.

You can switch to the left enine Crank, but same condition takes place. The crank switch does not return to center.

I signal External Airflow again and again, to no resolve.

Later this evening I will try using the right generator only to power the airplane in EXT, leave it for a while and then seeing if the left engine generator, which was off will get the airplane to work.


At this time, due to this issue, I am forced to allign the IRS after engine start.

[JonathanBleeker]

I see. I'm not sure what I can do as I don't handle the engine start code (our ADV dev is highly occupied with our commercial projects at the moment).

At this point I would suggest turning the GPU off and back on again after warm up is completed (before moving from STBY to ALIGN) and then starting the right engine while you align as that part is the quickest. You can also do a partial alignment and then restart it and it should go quicker.

[rnurse.bc]

Ok I understand.

But this is such a big issue because it prevents normal operation of the airplane, and you can't expect to allign the INS after startup, totally unrealistic as it burns WAAY too much fuel.

INS allignment normally happens on electrical power, before startup.

So, I would open up a new thread clearly describing the issue, expecting no reply, so that you can check it in the future. You would easily find it when ready to work on it.

Because I am continuously advertising this product, people are going to buy it. So you have to fix it, at your convenience though since you are busy.