The amount of air traffic worldwide is increasing, with an adverse effect on aircraft noise in the vicinity of airports as a result. Measurements and calculations have complementary benefits and limitations for the assessment of aircraft noise. A common method for the calculation of aircraft noise is ECAC Doc. 29. Various improvements of this method have been developed and studied in the past. However, research often lacks large numbers of measurements to validate these findings. The current study examined the effect of ECAC Doc. 29 model improvements on the differences between measured and calculated aircraft noise levels. The two improvements addressed in this research are: (1) The use of actual instead of standard meteorological conditions and (2) the use of derived flight performance instead of standard flight performance profiles. The calculated results have been compared with NOMOS measurements, the network of unattended microphones around Amsterdam Airport Schiphol. Using 151,108 flights and 385,001 NOMOS measurements, it was found that the difference between measurement and calculation depends on type of operation, aircraft type, and position of the microphone. The use of actual meteorological conditions showed the ability to reduce variability due to temperature, relative humidity, and pressure. The use of derived flight performance showed the ability to reduce variability due to wind up to 8 m/s. However, the absolute difference between measurements and calculations did not decrease for both improvements. Additionally, the aircraft substitution corrections were assessed. The substitution corrections based on ICAO type code showed smaller differences between measurements and calculations compared to the corrections based on aircraft configuration. It is suggested to study the substitution corrections further in the future. Moreover, it is advised to make use of the advancements in air traffic operations research for noise calculations based on derived flight performance.

Mountain ranges all over Earth have long been tourist attractions for their monumental size, beautiful nature, clean air and possible leisure activities. Though attractive, mountain activities may form a threat to human safety. Search and rescue (SAR) teams are constantly stand-by and often have multiple rescue sorties per day. These missions are slow and dangerous for the involved personnel. In extremely rare cases rescue missions use helicopters for search by pilot eyesight. These mission types on average cost e3, 300 per hour, are dangerous for personnel, have a small endurance and have a large downtime. There is a clear need to improve effectiveness and safety of these rescue missions...