Guy S. Brown, Richard L. Sulzer

In a flight test at a small airport, rectangular aiming-point markings with and without the additional use of a low-cost version of the red/white simplified abbreviated visual approach slope indicator (SAVASI) served as daytime approach guidance aids. Results showed that approaches made with the SAVASI were less variable in measured approach slope, and approaches made in the last half-mile before landing were nearer the 4 degree SAVASI glidepath angle. On average, approaches made either with or without the SAVASI were deeper than 4 degree, and tracking of itinerant aircraft not informed of the testing confirmed that the usual approach for small aircraft at this runway was in the t to 6 degree range. This indicates that future installations of SAVASI or related guidance aids should be made after measuring the normal practice at a given airport. Test pilot opinion was that the SAVASI was easy to use and provided good guidance in the vertical plane and that the rectangular aiming-point markings were beneficial.

Constantine Sarkos

The purpose of this report is to document visual aids (vugraphs) presented at a progress review meeting convened at the National Aviation Facilities Experimental Center (NAFEC) on July 25, 1974, for activity 181-521-010.

Paul Sawko

Various coatings and coating processes were evaluated in a program aimed at improving the hydrolytic stability of reticulated polyurethane baffle material {1}. This material is used in fuel tanks of aircraft and ground vehicles such as racing cars to prevent sloshing of fuel and thereby reduce explosion hazards. The most commonly used foam of this type of hydrolytically unstable and, depending on the environment in which it is used, gradually degrades over a 1 to 3 year period.

Potential moisture barrier coatings, which were evaluated, include Parylene, epoxy-polyether-based polyurethane’s, polysulfides, polyolefin rubbers and several other materials. The greatest improvement in hydrolytic stability was provided by Parylene coatings of 0.2 mil (5 x 10 cm) or greater thickness, and the second best coating, in terms of hydrolytic stability, was Astrocoat 8000, a polyester-based polyurethane.

Eldon B. Nichols

To determine the fire resistance, flammability and smoke characteristics of rail transit car body structural panels and materials.

Roman M. Spangler, Jr.

A DeHavilland DHC-6 Series 100 Twin Otter was flown by five pilots of varied experience on 7.5 degree steep-gradient approaches onto a ground level STOL runway. Forty (40) approaches and landings were accomplished using an angle-of-attack indicator (airspeed indicator blocked out) as primary speed control. Pilot performance as compared to performance with the airspeed indicator as primary speed control was slightly improved. A series of 6 degree steep approaches was made in simulated certification landing tests with dry and wet runways at various water depths. Runway friction, stopping, and landing distances were measured, and stopping distance ratios are shown. Maximum vertical touchdown velocities on steep approaches were also evaluated.