DIN 45643 "Measurement and assessment of aircraft sound" corresponds to a fundamental revision and summary of the three parts of DIN 45643:1984. The determination of aircraft sound specified in this standard applies for the vicinity of airports and areas in which aircraft sound is present. The standard is not applicable for low-level flying military aircraft sound. The standard deals with parameters for the description and assessment of aircraft sound and describes the requirements for measurement instruments, measurement installations and the evaluation of unattended measurements. This also comprises the aircraft sound measurement installations according to Article 19a of the German Civil Aviation Law (LuftVG), which are to be installed and operated in the vicinity of airports or airfields according to Article 4, Paragraph 1, Nos. 1 and 2 of the Act on Protection against Aircraft Sound. The aircraft sound measurement installations serve the continuous registering measurement of the sound generated by approaching and departing aircraft. These installations are referred to in this standard as aircraft sound monitoring systems. In this standard, quantities and parameters for the measurement and assessment of aircraft sound are defined for different applications. These values are defined both regarding the requirements for aircraft sound measurement installations according to Article 19a of the LuftVG as well as in regards to the use of other relevant standards. The determined values for rating parameters according to this standard can be used for comparison with guideline or limit values, as long as the rating times and methods correspond. However, such guideline or limit values are not specified in this standard. In addition to the current legal basis, international standardization has also been taken into account. In contrast to International Standard ISO 20906:2009 "Acoustics - Unattended monitoring of aircraft sound in the vicinity of airports", from which contents have been incorporated into DIN 45643, DIN 45643 takes into account national characteristics and requirements. The Committee responsible for this standard is NA 001-01-02-01 UA "Fluggeräusche" ("Aircraft noise") at DIN.