PPRuNe Forums - View Single Post - Classic B747 - Electrical relationship between Ignition & Engine anti-ice!
Old 6th April 2002 | 02:44
  #14 (permalink)  
tinyrice
 
Joined: Aug 2001
Posts: 147
Likes: 0
From: Minneapolis, MN,USA.
Is this a JT9D powered Classic, or one of those "bastardized" versions? If its a JT9D, the only connection that comes to mind would be to ensure that either start switch electrical system, and thus its associated ignition, doesn't have some fault that prevents the pylon valve or high stage valve from functioning correctly. The Nac A/I valve is electrically actuated, air operated. Potentially then, the Nac A/i valve might not get sufficient flow and temp air for de-ice / anti-ice for Take-off if either valve's stuck somewhere they shouldn't be. When you dexterously advance the throttles,the high stage closes and the core engine provides all the air. That said,the high-stage and pylon valve lights should clue you to these failure modes. It's weak but it's all I got..............
tinyrice is offline