As we know at the FAA its either black or white...so i found this interesting document. Its an extract from an email referring to NORDO aircraft.
" Since the Northwest overflight of MSP a couple of years ago,the FAA is hot and heavy on NORDO's I.E lost comms.
They make us hunt down aircraft like crazy.Since Jan 2012, the FAA has implemented a new quality control system and before a NORDO was handled by each facilty,now we just report the aircraft NORDO and a report is filed as to how long the were out of comms.Those reports go straight to the Regional Quality Assurance office and they determine wether or not to file a pilot deviation.The new standard is 20 minutes.If it is longer than 20 minutes,the Regional QA. Sends the pilot deviation report to FSDO.Not much we can do about it anymore,just make sure talking to ATC every 20 minutes"