73 Whaddya Got

Question 1

• The Eng 1 Hyd Pump is off
• A LOW PRESSURE light is cycling on & off above the Elec 2 Hyd Pump
• System A Flt Control LOW PRESSURE light cycling on & off
• MASTER CAUTION cycling on & off
• Amber FLT CONT annunciator (left side) cycling on & off
• Amber HYD annunciator (right side) cycling on & off

Answer 1

Since the #1 Engine Hydraulic Pump is off, the #2 Electric Hydraulic Pump is the only source of hydraulic pressure for System A. The lights may cycle during period of heavy system demand. This is normal.

Question 2

• You’re at high altitude
• Both hydraulic LOW PRESSURE lights on Side A are cycling on & off
• MASTER CAUTION cycling on & off
• Amber HYD annunciator (right side) cycling on & off

Answer 2

This is a result of foaming of the hydraulic at high altitude because the system is not properly pressurized.

Question 3

The EEC switches both go from white circle EEC to white circle EEC + amber ALTN … and you have a DSPLY SOURCE 2 annunciation shown towards the bottom left of the PFD.

Answer 3

The EEC’s take inputs from all sorts of places, including (bizarrely) the displays. So, if there is a display fault, the EEC’s will operate in a degraded mode. Deal with the EEC problem first, then the DSPLY SOURCE problem.

Question 4

You get an amber STANDBY PWR OFF light.

Answer 4

One or more of these busses are not energized:
AC standby bus
DC standby bus
Battery bus