Abstract: A combined altitude and height-above-ground indicator for an aircraft enables the altitude and the height of an aircraft to be displayed simultaneously. The combined indicator includes a first sensor and a second sensor which respectively sense altitude and height above ground, means for processing the information supplied by the first and second sensors, and means for displaying the sensed altitude and height-above-ground information by superimposing the altitude and height-above-ground information on the same scale against a pointer. The scale includes a transparent first part which represents a pressure-altitude display, and a second part which is a mask positioned under the first part so that it masks the background of the indicator for altitude levels which are below the measured height above ground.

Abstract: A combined altitude and height-above-ground indicator for an aircraft includes a first sensor and a second sensor which respectively sense altitude and height-above-ground, a processor for processing the information supplied by the first and second sensors, and a display for displaying the altitude and height-above-ground information, showing the two items of information against each other, on the same scale against at least one pointer.

Abstract: The invention relates to a compound of formula (I) ##STR1## Wherein: B is adenine, guanine or hypoxanthineZ is hydrogen or a negative chargeR is --[CH.sub.2 CH(R.sup.1)--O].sub.n -R.sup.2, --CH.sub.2 CH.sub.2 X, in whichR.sup.1 is hydrogen or (C.sub.1 -.sub.6) alkylR.sup.2 is hydrogen or (C.sub.1 -.sub.6) alkyln is a number from 1 to 6X is OH, F, NR.sup.3 R.sup.4R.sup.3 and R.sup.4 are independently from each other hydrogen or (C.sub.1 -.sub.6) alkyland to methods of enzymatically treating these compounds with biocatalysts having cyclic phosphodiesterase activity.

Abstract: The present invention concerns a device for indicating the position of an aircraft (H) notably a helicopter (H) with respect to a beam (F).In accordance with the invention, said indicator includes fixed first means (6) indicating the position of said aircraft (H), movable second means (7) indicating the position of the beam (F) in a predefined direction with respect to said aircraft (H), and third means (8) indicating which way to steer the aircraft (H) in the predefined direction to capture the beam (F) to said third means (8) being activated only when the aircraft (H) has crossed the beam (F) completely and is outside it.