Why ALWAYS APU first?

[Woc 21]

Hi captains,

 

My question is why in almost all FSX aircraft addons tutorials I've seen out there, after turn on the battery (or batteries), right away the next step is turn on the APU, when in real daily airliners operations, most of airlines policy is turn on the APU just a few minutes prior pushback? PLEASE, don't take this thread as a negative criticism, since I feel a deep respect for ALL of those people who spent time to nicely prepare a tutorial which will later helps thousands simmers (like me!) around the world. I really appreciate it. Just wondering why don't include this procedure as airlines really do it (huge most of cases I'm sure simmers who prepare tutorials, know this real airlines procedure). Sorry if this thread is an "out-of-topic" one.

[cyclobs 18]

The reason why airliners probably wait until pushback to turn on the APU is that they have GPU power connected and so they don't require the power (and air) from the APU until they have to plug the GPU to move the plane.

 

That doesn't mean all airliners are like this there are a few that don't use the GPU services from the airport and use APU only.

[AirborneZed 168]

In the case of using APU only before push,the relistc way of doing it would be using external power or GPU after turning on the battery.

[EGLL77W 1,508]

I'll put it down to a preference/habit. My NGX panel state is just a slightly modified 'Long' panel state that PMDG give you. I have the GPU & Air connected from start up - so I start the APU just after the Departure Briefing normally.

 

Don't worry - we'll be starting with the GPU connected on my B777 tutorials (-;

[Woc 21]

Right guys, I know this. Nowadays almost all airports have GPU units and for none is a secret how high is the fuel price (also keep in mind many noise reduction aviation administration laws). All this said, my question is why many of simmers who build FSX airliners tutorials don't take this into account

[FLEX1978 373]

Likely because 99% of tutorials are trying to teach you how to operate the aircraft, carry out the preflight, program the FMC etc etc.

 

Starting the APU first or hooking up the GPU first is more down to specific Airline SOP or restrictions at a particular airfield. As long as you have power to the aircraft to continue the tutorial it really doesn't matter how you achieved it.

 

Just to give you an example, out here one of the largest 777 & A3xx operators in the world generally keep the APU running during turnarounds, especially during the summer.

 

Regards

[Budbud 227]

 

 

Nowadays almost all airports have GPU units and for none is a secret how high is the fuel price

 

Keep in mind that GPU is not free and in some airports, it doesn't make much difference in terms of cost. Also APU provides air to the A/C, and in some hot weather, the ground air is not sufficient to cool down the cabin.

[Woc 21]

Just to give you an example, out here one of the largest 777 & A3xx operators in the world generally keep the APU running during turnarounds, especially during the summer.

Won't name it here but I can imagine what "middle east" airline you're talking about. I really don't think they have major problems to get fuel.

Starting the APU first or hooking up the GPU first is more down to specific Airline SOP or restrictions at a particular airfield. As long as you have power to the aircraft to continue the tutorial it really doesn't matter how you achieved it.

 

It make sense. Seems like don't really matters which power source is turned on first. Perhaps is my particular point of view about flight simulation. If we "fly" airliners within FSX, X-Plane, etc as real world operators do, then let's "operate them" in the same manner as well. But I repeat, is just my particular opinion about it. In FSX my habit is once in the flightdeck, always get the power from the GPU and turn on the APU when the passengers start boarding (AES software).

[machine2035 176]

Won't name it here but I can imagine what "middle east" airline you're talking about. I really don't think they have major problems to get fuel.

Woc,

 

I don't think its that they don't care about the fuel cost, more that they need the APU on so they can have air conditioning. From experience in a mild temperature (28C), the cabin can get very hot, very quickly. Combine that with the harsh climate of the ME, and people would be getting heatstroke left, right and centre :unsure:

 

Unfortunately, ground air units aren't usually colocated with an aerobridge similar to what a ground power unit is, hence why you will find many airlines operating their APU while on a turnaround (a quick way to find out is just to see the heatwaves emitting from the APU exhaust).

[Fabo 213]

 

 

It make sense. Seems like don't really matters which power source is turned on first. Perhaps is my particular point of view about flight simulation. If we "fly" airliners within FSX, X-Plane, etc as real world operators do, then let's "operate them" in the same manner as well. But I repeat, is just my particular opinion about it.

 

Thing is, many simmers (not neccessarily you) figure that there is only one right, realistic way to operate an airliner "as an airline does", while there is almost as many ways to operate a 737 as there are airlines operating is. And even more, if you account airport variations.

 

Consider, for example, lowcost such as Ryanair or similar. These operate typically on turnaround time of around 25-30 minutes. Let's say an airport bills for GPUs on basis of an hour minimal, so it might be still cheaper for them to run the APU for 20 minutes. They might use the GPU though, if they arrive, say, 20 minutes sooner. Then there are the factors of APU noise control and climate... too many variables to say one way or the other is not right.

[G-CIVA 62]

My question is why in almost all FSX aircraft addons tutorials I've seen out there, after turn on the battery (or batteries), right away the next step is turn on the APU, when in real daily airliners operations, most of airlines policy is turn on the APU just a few minutes prior pushback? PLEASE, don't take this thread as a negative criticism, since I feel a deep respect for ALL of those people who spent time to nicely prepare a tutorial which will later helps thousands simmers (like me!) around the world. I really appreciate it. Just wondering why don't include this procedure as airlines really do it (huge most of cases I'm sure simmers who prepare tutorials, know this real airlines procedure). Sorry if this thread is an "out-of-topic" one.

Probably because 99.9% of these so called 'tutorials' are created by spotty 14-18yr old lads with hoarse voices...with little explanation behind their methodology - they do the things the way they do 'just because'.

 

Thing is, many simmers (not necessarily you) figure that there is only one right, realistic way to operate an airliner "as an airline does", while there is almost as many ways to operate a 737 as there are airlines operating it.

Nail right on the head!

[Jude Bradley 659]

Probably because 99.9% of these so called 'tutorials' are created by spotty 14-18yr old lads with hoarse voices...with little explanation behind their methodology - they do the things the way they do 'just because'.

 

 

Nail right on the head!

made me laugh with this :LMAO:

[pedroqe 12]

Here in Brazil, APU is used A LOT in every airport. GPU is not that common. So here, using APU is the most realistic way.

 

I think in the point of view of a tutorial in which you don't know anything about GPU cost or availability, APU might be more suitable, since it is always available. Plus, if you take realism that serious, GPU couldn't be connected and turned on via FMC anyway, you'd have to ask for connection and wait for confirmation, whereas APU operation is easier for newbies to understand and apply correctly.

[Tabs 2,790]

In the NGX Tutorial #2 I followed the Boeing flows and have the APU start where it was in that sequence - it might be earlier than some airlines would do it but I wanted to go with what was in the manuals that came with the product.

[Don t moderate me this way 882]

What about the 'flat battery bug'?

 

Some writers might have this bug in mind and may include a workaround in their tutorials by turning on the APU early.