the flight path, it is easy for the pilot to control precisely with built in corrections for the wind. Radar Guidance Accuracy - The accuracy of the radar tracking is 5 meters (rms) slant range, 0.05 degrees (rms) in azimuth and elevation. This gives an overall radar accuracy of about 8 meters at 2.5 miles range. The inertial velocity accuracy of the Inertial Reference System (IRS) is about 1 kt(rms).
The total accuracy of the radar guidance system described above for the HUD was determined by flight tests to be less than 5 meters.
Fig.16 Simulation Test of Radar Guidance
SIMULATION TEST RESULT 17)
Fig.16 shows the second simulation test results for the Radar Guidance evaluation test described previously. The test started from a distance 2 nautical miles, height of l000 feet and lateral deviation of 0.1 nautical miles. The aircraft approached to the per-spective runway by level flight correcting the lateral deviation. After G/S capture the aircraft descended to the touch down point along the selected approach path of 6 degrees. The flight condition and the test condition are shown in the Fig.16.
The tests were evaluated by the G/S and Loc. rms error which were calculated during the height from 900 feet to 300 feet. This simulation tests were done to evaluate for no HUD, Radar Guidance V.V. mode and and Radar Guidance A mode on VMC, and for *.he Radar Guidance VV mode, A mode, B mode, and C mode on IMC(Category II). The Radar Guidance V.V. mode is basically same format of the Radar Guidance A mode only without the Perspective runway. The results shows that there are no large difference between no HUD and all Radar Guidance modes for VMC and IMC. But no HUD on IMC was not done in this simulation tests as shown in Fig.16.
FLIGHT TEST RESULT
The HUD was used for all 97 flights of Aska flight test program. The digital airspeed indicator had better resolution than the original analog indicator and the flight path acceleration symbol gave good controllability of the velocity. The pitch scale and heading tape had better resolution than normal ADI and HSI instruments and did not disturb the pilot's view because these symbols are in harmony with the outside view. The flight path symbol had a much higher response rate than the normal rate of climb indicator and was particularly useful for approach and flare control, especially in the ground effect region.
Two pilots and two research engineers from the NASA Ames Research Center came to JAPAN for an evaluation of the Aska They spent one week on the flight simulation of the Aska and made five flight evaluations of the aircraft during a two week period.
There were no problems in the use of the HUD system. They used the pseudo modes for up and away evaluations and the radar guidance modes for landings. The Pseudo/Radar guidance B mode was used for landing evaluations. Because of their experience with the NASA QSRA powered lift aircraft, they were able to help significantly with the Aska flight test program. They gave us several very useful comments on the Aska program.
The results of the NASA flight are as follows:
1 Excellent precise landing 8 m dispersion for 3 landings with radar guidance mode(see table 2)
2 Evaluation of the one engine failure Take-off and Landings
3 Demonstration of a new Landing Configuration and new Take-off procedures
