THISL

AcronymDefinition
THISLThematic Indexing of Spoken Language
References in periodicals archive ?
Meeker, descend via the LEEHY THREE," would mean you would fly Meeker to Myton at FL240, Myton to THISL at FL210 and so on.
So the right move would be to drop to 16,000 without waiting for THISL, but then remain at 16,000 even if you cross SPANE.
Comply with the restrictions." This means you remain at FL240 until Myton, fly FL210 from Myton to THISL, but then remain at 16,000 feet until given further instructions.