Just to clairfy, at NWA, a seniority list instructor was required for all "motion on" events.
You could only teach on an aircraft you were currently holding. If you lost your seat, you lost your IP job as well (but nothing stopped you from applying for your new aircraft).
In practice, you needed at least a years experience on the aircraft before they'd consider you for an IP position, unless you had a LOT of IP/Checkairman experience. Even if the contract permitted it (which it didn't) the likelihood of getting an IP job on an aircraft you had no experience on would have been zip.
Nu