Public reporting burden for this collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing the collection of information. Send comments regarding this burden estimate or any ether aspect of this collection of information, including suggestions for reducing this burden, to Washington Headquarters Services, Directorate AFRL-HE-WP-TR-2001-0130 SUPPLEMENTARY NOTES 12a. DISTRIBUTION AVAILABILITY STATEMENTApproved for public release; distribution is unlimited. 12b. DISTRIBUTION CODE ABSTRACT (Maximum 200 words)This report presents the results of the third in a proposed sequence of studies to investigate human annoyance to noise from low-altitude military training route (MTR) flight operations. The sequence ranges from laboratory studies, in which the physical and social parameters are well controlled, but highly artificial, to field attitudinal surveys, in which these parameters are largely uncontrolled, but the setting is natural. In this third study, subjects were exposed to both real and recorded MTR noise events in their own homes for a period of four weeks. In the laboratory study it was found that MTR sounds having onset rates faster than 30 dB/second caused annoyance beyond what would be expected from the corresponding sound exposure level (SEL). The best fit to the data was found to be an onset rate adjustment to SEL, which has the form of a linear relation on a dB versus log (rate) scale, from 0 dB at a rate of 30 dB/second to 11 dB at 150 dB/second. The rented home study confirmed the laboratory onset rate adjustment, although the adjustment was found to begin at 15 dB/second rather than at 30 dB/second. The present study continued to confirm the existence of an onset rate effect. It also confirmed the equal energy principle. However, it did not show any dependence of annoyance on the sporadicity of the events.