1. Title of the invention
Angle Of Attack (AOA) approach Indexer for carrier landing aircraft
2. Field of invention
AOA approach Indexer will be used for aircraft applications
3. Use of invention
The AOA approach Indexer provides a head up display of angle-of -attack (or airspeed) information in the form of three illuminated signáis. The central amber circle or "doughnut", comes on when the aircraft is in the optimum landing AOA range. The lower (red) and the upper (green) chevrons indícate that AOA is too low or too high for landing, respectively. They also indícate, by the direction of the chévron angle , in which direction to change the AOA so as to achieve the correct AOA for landing.
4. Prior art
An AOA approach Indexer comprises of three lamps. Conventíonally the lamps of the AOA approach Indexer are of simplex type. The indexer accepts only a single input for each lamp. In case of any fault or a wíre cut, the indicator will not light up thus depriving the pilot vital information while landing on a carrier.
5. Draw backs of prior art
The AOA approach Indexer is of simplex type. It accepts only a single input for each lamp. In case of any fault or a wire cut, the indicator will not light up thus depriving the pilot vital information during landing in a carrier.
6. Comparison between prior art and present invention
In the present invention, the AOA approach Indexer is quadraplex type as against simplex type in the prior type of indexer. The reliabilíty of the indexer is higher in a quadraplex type when compared to simplex type. Also the present invention is a compact assembly of three lamps occupying minimal space.
7. Aim of the invention
The aim of the invention is to provide a quad redundant AOA approach Indexer in order to interface with a quad redundant fly by wire computen
8. Summary of the present invention
The AOA approach Indexer, located nearthe Head Up Display in the cockpit, consists of three indexer lights. The upper Chevron (V) ¡s green and indicates a high AOA. The centre donut (O) is amber and indicates the optimum AOA, and the lower chevron (A) is red and indicates a low AOA. Two intermedíate conditions are also indicated by illumination of the donut (O) with the upper or lower chevron. The Indexers provide the principal reference for controlling airspeed during carrier landing approaches.
9. Brief description of drawings
10. Statement of invention
The AOA approach Indexer, located near the Head Up Display in the cockpit, consists of three indexer lights. The upper Chevron (V) is green and indicates a high AOA. The centre donut (O) is amber and indicates the optimum AOA, and the lower chevron (A) is red and indicates a low AOA. Two intermedíate conditions are also indicated by illumination of the donut (O) with the upper or lower chevron. The Indexers provide the principal reference for controlling airspeed during carrier landing approaches.
11. Detailed description of invention
AOA approach Indexer provides the pilot with a head up display to assist ¡n optimizing the aircraft speed and Angle of Attack during final approach on a carrier. This display informs the pilot whether the aircraft is approaching too fast, too slow or at optimum speed. The High indication presented when the upper green chevron (V)iHuminates., alerts the pilot that the approach speed istoo slow and the nose should go down by increasing power. The Low indication presented when the lower red chevron illuminates (A)/ alerts the pilot that the approach speed is too fast and the nose should go up by decreasing power. The amber O in the middle of the indexer when illuminated alerts the pilot that the approach speed is optimum. Two lights are illuminated during transition. i.e. when the aircraft configuration is between optimum and high/ both the." O" and "V" lamps will be illuminated.
The indexer accepts twelve open-ground input signáis from the computer to ¡Ilumínate the appropriate lamps. Each of the three lights has four inputs for drivíng the indexer. The four inputs are provided by the flight control computer which is a quadraplex system. Henee each light has 4 redundant inputs. This increases the reliability of the indexer.
Also the assembly of the lights is a compact arrangement occupying mínimum space.
12. Drawings &Worked examples
TitleLAngle Of Attack (AOA) approach Indexer for carrier landing aircraft

Claims
We claim thát
1. The AOA approach indexer displays to the pilot the deviation frorh the datum AOA selected for Approach on a carrier.
2. This is a quad AOA approach indexer for better redundancy.
3. AOA approach indexer can be integrated on anytype of aircraft intended for carrier take-off and landing applications with compatible interface sy'stem.
4. The compactness and simple interface technique (both mechanical and electrical) of the AOA approach indexer make it feasible for easy installation or removal on aircraft.
5. With modularization approach in the design of AOA indexer, improvement in maintainability is achieved.