CRJ-200 – Quicktips – AC External Power and Service Config
Posted by Jeffrey on January 9th, 2009
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There are two very small AC power functions on the CRJ200 you should know about. I’ve combined them here because they basically compliment each other.
When you pull into the gate or arrive at the airplane from an overnight or airplane swap, in order to save some jet fuel, consider having External Power connected, if it isn’t already. You will save hundreds of dollars in jet fuel, decrease the wear on the Auxiliary Power Unit (APU), and reduce noise associated with the APU, which can be very loud!
In my experience, I have seen two different ground power sources:
1) ground power from the terminal via an electrical cable
2) an engine-driven ground power unit (GPU)
CRJ200 Electrical Power Service Panel
Now, if you arrive at the airplane and one of these is hooked up, you will see a green AVAIL light on the Electrical Power Services panel over AC. This indicates that the electricity being provided is the correct FREQUENCY, PHASE, and VOLTAGE, and that it is safe to use.
Beware though! There have been many times when I’ve stepped into the airplane and it was already powered up but the Master Switch was not selected to ON.
Maintenance or more likely ground personnel had moved the airplane from its overnight location to the gate, attached the ground power and pressed the AC AVAIL pushbutton and never turned the Master Switch ON. For reasons I’ll explain in another entry, this could cause the Air Driven Generator (ADG) to deploy on the ground and then you have a real mess on your hands.
AC External Power
CRJ200 - AC Synoptic - AC External
The proper use of the AC External Power is to have ground personnel connect the cable. Check that the BATTERY MASTER switch is selected ON. Check the AC Synoptic Page and insure you have the correct voltage and frequency. Next, check the ELECTRICAL POWER SERVICES panel and insure that the green AC “AVAIL” light is illuminated. Press the AC “AVAIL” pushbutton in and now you have all the electrical power you need to pre-flight the airplane.
A few problems that I’ve had with ground power is that the external plug will occasionally fall out or be too loose to stay connected or the power itself will trip offline. You will see power trip off most often when you check the hydraulics because the hydraulic motors use a lot of electricity and sometimes the ground power just can not handle the electrical load.
If this happens, then it might be time to start thinking about using the APU.
AC Service Config
CRJ200 - AC Synoptic - Service Configuration
This configuration will most often be used by ground personnel when they clean the airplane on an overnight.
With ground power hooked up, and the SERVICE CONFIG button pressed on the AC Service Panel on the right side of the nose of the airplane, the interior lights and cargo lights will have power but basically nothing else. Only UTIL BUS 1 and UTIL BUS 2 are powered. Also, note the “SERVICE CONFIGURATION” in the top left-hand corner of the synoptic page.
If after you power down the airplane, the rampers complain that they have no lights in the cargo bay but ground power is hooked up and working (you will know because of the green AVAIL light is illuminated), the problem is usually that the SERVICE CONFIG button is not pressed in.
As a side note, during SERVICE CONFIG operations, there is no AC cooling going on but that is fine because the main displays (MFD1(2), PFD1(2), and ED1(2)) are not powered.
Anyway, there you have it, two minor systems of the CRJ200 that are essential to ground operations. The next time you are in the airplane. Have a look at the panels that I’ve mentioned as well as the synoptic pages. It will tell a story!
Be safe…
Jeffrey
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Forums worth visiting:
- Airliners.net - Nice picture of the flight deck on the CRJ-200.
- AirlinePilotForums.com – Good source of information for aspiring pilots.
- AirlinePilotCentral.com - One of the best sources for information anywhere.
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