WHAT IS NOTAM?

Pilot and Aeronautical Information Notices to Airmen(NOTAMs) Notices to Airmen, or NOTAMs, are time critical aeronautical information either temporary in nature or not sufficiently known in advance to permit publication on aeronautical charts or in other operational publications. The information receives immediate dissemination via the National Notice to Airmen (NOTAM) Sytstem. NOTAMs contain current notices to airmen that are considered essential to the safety of flight, as well as supplemental data affecting other operational publications. There are many different reasons that NOTAMs are issued. Following are some of those reasons:

*Hazards, such as air shows, parachute jumps,kite flying, and rocket launces

*Flights by important people such as heads of state

*Closed runways

*Inoperable radio navigational aids

*Military exercise with resulting airspace restrictions

*Inoperable lights on tall obstructions

*Temporary erection of obstacles near airfields

*Passage of flocks of birds through airspace (a NOTAM in this category is known as a BIRDTAM)

*Notifications of runway/taxiway/apron status with respect to snow, ice, and standing water
 (a SNOWTAM)Notification of an operationally significant change in volcanic as or other dust contamination (as ASHTAM)

*Sofware code risk announcements with associated patches to reduce specific vulnerabilities.


Source:

https://www.faa.gov/regulations_policies/handbooks_manuals/aviation/media/pilot_handbook.pdf