1977 Volume 1977 Issue 16 Pages 15-33
Analysis has been made on altitude deviations of aircraft, B747s and DC10s.
Aircraft were on scheduled services between Tokyo and Chitose.
Data were collected from 25 to 27 July 1976 and flights were at 31,000 to 35,000 feet. A total of 336 samples were extracted from 35 flights.
The device used for measuring altitude deviations was the Mitsubishi Slotted Array Height Measuring System. This is a breadboard model of a 3D Radar we have been trying to develop for an ATC use.
The system provides a continuous record of an aircraft altitude. The result of an aircraft altitude calculation is marked out on both the printer and typewriter at an interval of 25 seconds. A complete configuration of this system is shown in Figure 4.
The data in the study were obtained by the system. It was, therefore, possible to evaluate altitude deviations from a cruise altitude in terms of the magnitude of altitude fluctuations of an aircraft operated at a high altitude.
We have expressed the analysis results in terms of standard deviation of fluctuation errors. If the system accuracy was assumed to be from 50 to 75 feet in standard deviation at a range of 20 to 30 nautical miles from the system, the result showed that the magnitude of altitude fluctuations was within ±250 feet, and 80 feet in standard deviation for the altitude range in which the data were taken.
