Post by CoolP on Oct 27th, 2010 at 1:54am
I think it's mainly without external air, but I'll check this and report back.
No. 3 startup on "high pressure" and without external air and power works. The "L. H. Bottle" comes up then because you've used up the one shot. Nice feature now, if it gets explained.
I like to mention that the manuals don't explain this, Lou did. Thanks!
If you open the bleed valve after the engine 3 start, you get all other engines running too with a "low pressure" start. The No. 3 bleed pressurizes the system and you then can start 4, 2 and 1 and gain more stable pressurized air with every start.
That's how it should be and that's how it works on this 707.
If you need air for the AC and Packs then, the Air Compressors have to be enabled, these are a 707 special, the modern jets do this via their bleed air too.
Still leaves this one as open and new
There shouldn't be any "low pressure" readings when the external air is not connected, the engines are off and the AC too.
Quote:
There currently always is a flow although no system is feeding it and there is no "green band" on the gauge.
Am I right?
No. 3 startup on "high pressure" and without external air and power works. The "L. H. Bottle" comes up then because you've used up the one shot. Nice feature now, if it gets explained.
I like to mention that the manuals don't explain this, Lou did. Thanks!
If you open the bleed valve after the engine 3 start, you get all other engines running too with a "low pressure" start. The No. 3 bleed pressurizes the system and you then can start 4, 2 and 1 and gain more stable pressurized air with every start.
That's how it should be and that's how it works on this 707.
If you need air for the AC and Packs then, the Air Compressors have to be enabled, these are a 707 special, the modern jets do this via their bleed air too.
Still leaves this one as open and new
There shouldn't be any "low pressure" readings when the external air is not connected, the engines are off and the AC too.
Quote:
| 1. Conditioned Air Duct Pressure Indicator Displays pressure differential between main cabin and distribution duct. Reflects ventilation flow rate. 6-10 INCHES – Desired operating rate. GREEN BAND – Operating range. |
There currently always is a flow although no system is feeding it and there is no "green band" on the gauge.
Am I right?