"Marc Lattoni" wrote in message
news:c3%hc.1386$2q2.192@edtnps84...

Do modern airliners not have an alternate static source as on my 172?


Modern airliners have multiple static ports, but they do not have one like
your 172. The alternate static port in your 172 uses cabin air. Airliners
are pressurized, so an alternate static port like on the 172 would be
worthless.