Questions and Answers – Vacuum System TroubleshootingWritten by Steve Ells
Q: Dear Steve,
I own a Piper PA-28-181 and I have a vacuum system problem. From what I understand, the vacuum system in my Cherokee is similar to a lot of other single engine Pipers, so this is likely a system problem rather than a Cherokee problem, but here goes.
As I climb, the vacuum pressure drops off. On the ground it’s right in the middle of the green but the needle slowly moves toward the left side of the gauge as I climb. Above 7,000 feet the pressure indicates below the green arc.
During my private pilot school I was taught that it’s important to keep the needle in the green but I’ve kept a close eye on both the DG and artificial horizon instruments when the vacuum level drops and they both seem to indicate correctly.
Can you tell me what’s going on? What do I need to do to fix it?