AIR FORCE LANDING SYSTEM

e [Music] low visibility no Prospect of a change for hours under such conditions a pilot calls upon radio to become his eyes the pilot who knows his radio and his instrument flying can utilize special radio AIDS in conjunction with his instruments to land safely even in most adverse conditions by following the Air Force instrument Landing system when a pilot wishes to make such a landing uses radial compass for approach alignment a special Runway localizer to determine Runway position the altimeter for altitude the directional gyro and Artificial Horizon involing his Glide path and the marker Beacon receptor for locating the two special guidance stations these guiding stations are usually established in trucks so that they may be moved about and set up according to wind conditions each station is equipped with a radio Compass locator and a beam projector which actuates the marker Beacon receptor in the airplane a new device now being added to the basic Compass locator system is the runway localizer which operates as a miniature range station The Guiding stations are set up on the downwind side of the field the interstation is established near the edge of the field the outer station is located 3 and2 miles from the Inner Station the runway localizer is placed on the upwind side of the field thus a line drawn from the outer station through the interner station and the runway localizer is Into The Wind and straight along the runway following the radio range an airplane approaches the field on which it is desired to make an instrument Landing homing with a radio compass it is flown to the Inner Station here the compass immediately is tuned to the outer station thus the approximate Runway alignment is determined and set up on a directional gyro at the outer station a turn is negotiated and altitude is loost so that the airplane returns to the station at a specified height here the compass is immediately tuned to the Inner Station while flying in on the compass the gyro is checked and the exact Runway alignment is established meanwhile as seen here in a side view a Glide has been started so that the airplane will reach the Inner Station at a predetermined altitude from the interstation to the actual Landing a steady Glide is held the compass is disregarded and control is maintained by the runway localizer the directional gyro and the Artificial Horizon thus the basic principles of the instrument Landing system can readily be seen by alternately tuning His Radio Compass to the two stations a pilot is able to determine the exact alignment of the runway and verify this by means of the runway localizer by coordinating this line with his altitude at two points of known distance from the field he is able to establish is heading and glide so as to affect the landing with no visual reference to the field the detailed procedure for making an instrument Landing will be demonstrated here on the instrument trainer where by leaving the hood off the Pilot's activities can be observed in the cockpit the flight path is accurately traced on the recorder arriving in the vicinity of the field the pilot contacts the tower to make sure that the instrument Landing equipment is set up and to secure field and weather information upon learning the field elevation pressure he sets it on his altimeter pressure scale the altimeter must be set with extreme acis so that the exact elevation above the field will be known at all times now to begin the actual Landing procedure he Tunes to the Inner Station and centers the radio compass at this time he also Tunes in the runway localizer and then turns on the marker Beacon receptor the directional gyro is caged at 180° to be used later at an altitude of about 1,000 ft he flies to the Inner Station a flash from the marker Beacon receptor indicates that he is directly over the Inner Station after receiving this signal the pilot Tunes to the outer station centers the radio compass and UNC cages the directional gyro at 180°. Guided by the radio Compass he flies to the outer station upon reaching the upper station he continues for 30 seconds at 180° on the gyro at the end of this time he executes an offset turn this is accomplished by first turning 60° to the right for 20 seconds and then executing a standard rate turn to the left for approximately 270° during the turn he slowly loses altitude to 800 ft the turn is stopped when the radio Compass is centered when the flash indicates that he has returned over the auto station the pilot does the following rapidly Tunes to the inner station properly centers His Radio compass resets the gyro if necessary to 0° and establishes a 400 ft per minute rate of descent by proper use of the throttle holding the airplane level or a little nose High by the Artificial Horizon Guided by the radio Compass he flies to the Inner Station when he reaches the inter station altitude should be 200 ft from this point he disregards the radial Compass continuing descent at 400 ft per minute he maintains control by means of the runway localizer the directional gyro and the Artificial Horizon on contact with the ground the AL reading zero he cuts the gun but continues to fly the airplane in Direction and Pitch until the tail comes down of its own accord the basic situation as demonstrated here applies to all instrument Landing problems there may be some variations in the initial approach but in every case the most satisfactory way to get in is to pick up the routine pattern as soon as possible in review we approach the southeast leg of the beam followed through to the cone of silence pass the inter station and the outer station made a procedure turnaround returned to the outer station and flew straight to the Inner Station and landed at the field in coming into land should an altitude of 200 ft be reach short of the inter station the airplane is leveled off at 200 ft arriv driving at the interstation a rate of descent is established as before at 400 ft per minute until contact is made on the other hand should the pilot find himself above the established altitude limit at the inter station he has no choice but to pull up go around and try for a new Landing the directional gyro and the Artificial Horizon are the principal instruments used in flying from the interner station to the field speed and vertical speed indications can be considerably smoothed out with the aid of the Artificial Horizon as long as it functions correctly it has no lag and its indications require virtually no interpretation on the part of the pilot for losing altitude and Landing the Artificial Horizon is held in the same position as for medium slow cruising in this slightly nose up position The Descent is more readily checked when power is applied than if a more nose down position were assumed when using the Artificial Horizon remember that as small a change as 132nd of an inch in the pitch indication corresponds to a one degree raising or lowering of the nose the Air Force instrument Landing system has been proved in actual service it is adaptable to many different types of airplanes with no fundamental changes it fits practically all sights and field conditions with a minimum of variation and it can easily be Mastered by pilots in a short time [Music]