747-400 Vertical Speed Display Query
 

The Boeing Maintenance Manual has this sentence about V/S indications...

"The scale defined for the 2000 to 6000 feet per minute range is extended to the upper or lower display range limit when the vertical speed exceeds the analog display range limit and the pointer parks in view at the upper or lower limit."

I'm having trouble understanding it.

According to the manual, the adjacent digital fpm display (which appears if V/S's are above 400fpm) has a limit of 9999fpm.

The 2000~6000fpm range is linear, according to the manual. If the scale and needle were to extend to 9999fpm, they would (graphically) interfere with the digital display.

http://www.ozemail.com.au/~b744er/Ve...SpeedScale.JPG

Has anyone seen this in the sim... or lived to see this display in real life? :}

Thanks.
Rgds.
NSEU

You see how there's still a little bit of space above the 6000 fpm climb and below the 6000 fpm descent (more on the descent)? Well, that's where the pointer would go, i.e. it would point above 6000 fpm climb, right to the very top of the grey bit and then it would stop. The actual grey bit is not added to when the limit is exceeded, just the needle goes further than the 6000 fpm line until it reaches the limit of the display, i.e. it is 'extended' beyond the limit line. Of course, the digital display will tell you what you're really doing.

Thankfully, never been there but the aerobatic aces of China Airlines and a few others have been, as I'm sure the NBO crew from BA would be able to attest :eek:

Thanks, Fratemate.

I thought it sounded too complicated to be true :)