From 18 June 1944, when it landed in France, until the present
date (3 March 1945) the 225th AAA Searchlight Battalion has performed many
assignments, including the defense of airports, the defense of seaports, and the
defense of bridges. The 225th is attached to the 51st AAA Brigade.
The greater part of these assignments has been the defense of airstrips, ranging
from the first strips constructed on the Normandy beachhead to those now
operating near the present front line in Northern France and Belgium.
The battalion's role has been a dual one, consisting first of the discovery and
engagement of hostile aircraft operating over or near objectives which it had
been assigned to defend, and second to assist the Allied air force in the performance
of its mission by means of homings, alerts, and a multitude of other services
through which its lights and radars have been able to be of assistance.
Airstrips which it has been defending have been directly attacked seven times by
enemy aircraft. Eight aircraft definitely identified as hostile have been
illuminated and many others have been engaged by the lights, which, although
they were not definitely identified, may be presumed to have been hostile due to
evasive action or other suspicious and unusual conduct observed. The battalion has
one confirmed Category I "kill" to its credit.
The comparatively infrequent appearance of the the German air force, however, has
without minimizing the primary defensive role of the searchlights, made it
possible to develop the secondary role of assistance to the Air Corps to a greater
and greater extent.
Of the various types of assistance which the 225th has been able to offer, unquestionably the
most frequently called for and the most important has been the homing of friendly
aircraft. These searchlight homings have come to be so valued that they are now regularly
used not only in the cases of lost or disabled aircraft, but also in almost all routine
night landings at airstrips around which this battalion's searchlights are deployed.
The homings have been given in a number of different ways, including canopies, beacons,
indirect homings, radar homings, the illumination of runways, and the use of lights during
daytime hours to illuminate the ends of runways during bad weather. Since reaching France,
a total of 1,922 homings of all types have been given. No accurate data have been
maintained as to the number of aircraft which landed safely under each homing, but
incomplete figures show an average of about two planes a homing, giving a total of
approximately 3,844 friendly aircraft brought safely back to base, with their
crews totalling approximately 12,000 airmen.
Two of the 225th's 800-million-candlepower searchlight beams stab the
night sky over Northern Europe. This must have been a welcome sight
for hundreds of Air Corps aviators as they returned from night missions
against the enemy.
The homings have proved of particular value to night fighters, which normally
return to base during the hours of darkness. The 2nd Platoon of Battery A became the
first searchlight unit in this theatre to work with night fighters, when, early in
August 1944, it was assigned to the field on which the 422nd Night Fighter Squadron
was operating. It has remained with this squadron without interruption since that
time. A month later, the 1st Platoon of Battery A began working with the 425th Night
Fighter Squadron and has continued to function with that unit ever since.
The value which these two squadrons place on the assistance given by the homing lights
is reflected in commendations received by the searchlight platoons from the commanding officers of the squadrons. In commending the 2nd Platoon of Battery
A, Lieutenant Colonel Oris B. Johnson, commanding officer of the 422nd Night Fighter
Squadron, says, in part:
"It is believed that the squadron operations would have been
cut down to at least 25% without the searchlights. The platoon
has enabled the squadron to fly in much worse weather than would
have been possible without the lights. In addition, they have
materially aided in the landing of aircraft when the weather has
turned bad unexpectedly."
In later official statements, Colonel Johnson has revised his estimate
upward, stating that if the platoon were taken from him, his combat efficiency would be decreased 50%.
Under the command of Lt. Col. O.B. Johnson, one of the P-61's greatest exponents, the 422nd Night Fighter Squadron was the leading P-61 outfit in the ETO, destroying 43 enemy aircraft in the air, five buzz bombs, and hundreds of vehicles, becoming the most successful night fighter Squadron of WW II. Nicolas Trudgian's dramatic study of the predatory Black Widow recreates one of the 422nd's typical air victories flying a twilight mission on 24 October 1944, Colonel Johnson and his radar operator have picked up a formation of three Fw190s; stealthily closing on their quarry in the gathering dusk, "O.B." makes one quick and decisive strike, bringing down the enemy leader with two short bursts of fire. Banking hard, as the Fw190 pilot prepares to bail out, he brings his blazing guns to bear on a second Fw190, the tracer lighting up the fuselage of his P-61.
In his commendation to the 1st Platoon of Battery A, Lieutenant Colonel
Leon G. Lewis, commanding officer of the 425th Night Fighter Squadron, writes:
"The aircrew members of this squadron take this opportunity
of expressing their gratitude for the aid and full cooperation
extended by the 225th AAA Searchlight Battalion. The aid and
cooperation have proved of inestimable value both in material
and psychological benefits.
Although night fighters, due to their tactical employment, offer far more opportunities for the lights to give homing assistance, homings have proved valuable to other types of Air Corps units. Photo reconnaissance squadrons, and other units whose aircraft frequently return from operational missions after the hours of darkness, have made use of the homings regularly while aircraft of all types have been assisted in returning to their bases that otherwise would have been lost or in distress as their fuel ran out.
On return from operational missions in several cases, the searchlight
canopy has been proved necessary for the safe return of our
aircraft. It has been the policy to illuminate the field
when planes are expected to return but have not yet contacted
the airdrome by radio. In one instance, the plane suffered
flak damage which destroyed the radio. The pilot headed in the
general direction of the base and was able to find the airdrome
by sighting the canopy. The pilot was particularly grateful because
he was returning with one engine inoperative and could not afford to
remain aloft for any length of time orienting himself by other
means. Due to weather conditions on the Continent, there have
been innumerable instances of our aircraft being airborne
when the ceiling has dropped below safe operating conditions or
fog has obscured the landing strip lights. The searchlight canopy has
been our only means of exactly locating the airdrome and completing a successful mission."
TYPES OF HOMINGS
Searchlight deployment The standard deployment for lights of the 225th when assigned to an airstrip is such that four lights (the number normally employed in a canopy) are situated in an approximate square around the strip, one light near each end of the strip and one a short distance off to each side near the middle of the strip. The lights at each end of the strip are placed approximately 350 yards from the end of the runway and 15 degrees off from a direct line with the runway, the offset being made to opposite sides at the two ends of the runway so that a direct line between the lights crosses the runway diagonally.
Procedure All light sections are given previously prepared azimuth and angle charts which permit them to form an intersection over the center of the airstrip at heights of from 300 to 10,000 feet. It has been found advisable to form the intersection as close as possible to the cloud base. If the returning plane is coming in under the cloud base, the lights are then clearly visible, while if he is flying above the clouds, the intersection on the cloud base has been found to create a glow above the base which can be seen by pilots at a distance of approximately 15 miles.
Normally, the canopy is called for by light control as a result of radio contact with the returning plane, which requests the assistance. As stated by Colonel Lewis is the previously quoted commendation, the night fighter squadrons also make a practice of ordering a canopy formed when they lose radio contact with a plane and have reason to believe he is in trouble. A number of badly crippled planes have been saved by this method. Occassionally a plane at some distance from its home base will be observed by searchlight sections to give distress signals. In such cases, flight control is immediately notified and usually orders a canopy formed immediately. Thus alertness on the part of searchlight sections has saved several planes, an outstanding example occurring near Airstrip A-58 on the night of 24 September 1944 when Section 4 of the 1st Platoon of Battery A picked up a plane showing no IFF (Identification, Friend or Foe). Upon illumination the plane proved to be a C-47 which immediately flashed an SOS on his downward recognition lights. A canopy was immediately formed and the plane landed safely. Lieutenant Potter of 9th Air Force Headquarters, pilot of the plane, called from Flight Control a few minutes later and stated that he wanted to thank every member of the searchlight platoon for their assistance, because he had been completely lost and had only 30 minutes fuel supply left.
Under extremely unfavorable weather conditions, the normal canopy can be implemented by the use of additional lights as waving beacons. If the planes desiring a homing are unable to see the canopy through the cloud base, other available lights play over the clouds, seeking a thin spot where they can break through. This technique was successfully employed by the 2nd Platoon of Battery B on 18 February 1945 at Airstrip A-64 when four P-47s asked for a homing during very bad weather and could not see the canopy. The waving beacons were then employed and were seen by the planes, which landed safely with their assistance. In this instance, the pilots were so grateful for the homing that they called each chief of section of the searchlight platoon personally to thank them.
In forward areas, when there has been any indication that hostile aircraft are operating in the vicinity, it has been found inadvisable to pin-point the airstrip by the forming of a canopy. In such cases, when homing assistance is needed, either one or both of the searchlights which, under normal deployment are placed near the ends of the runways, are exposed vertically as beacons. While these beacons do not indicate the exact location of the strip as accurately and have not so great a range of visibility as a canopy, they have been found to be satisfactory substitutes under most conditions and have been used as a homing aid more than any other method except the canopy.
Homing on adjacent airstrips
A less frequently used method of homing, but one which has been found invaluable in emergencies, is offered by those lights of the 225th which have been deployed around objectives other than airstrips and thus have not been able to form any canopies when planes have indicated, by distress signals or by other means, that they are need of assistance.
Such cases fall roughly into two classes: the first, in which the plane, by means of radio contact with an airstrip which does not have searchlights deployed around it, indicates that it needs help in finding a field on which to land, and the second, in which the plane, either because its radio is out of order or because it has been unable to contact an airstrip, is first able to make known its need of assistance by means of distress signals which are observed by searchlight sections. The first is known as indirect homing and second as direct homing.
Each platoon of searchlights designates two or more lights as those to give such homings and furnishes the sections manning them with the precise locations of nearby airstrips at which any aircraft might be expected to land. The homing lights are selected that so a homing can be given to any desired field without having the light give undesired illumination to an airstrip, a city, or any other high-priority area.
In the case of an indirect homing, the Air Corps officials contacted by radio determine to which field the plane will be homed and order the lights to home on that field. Certain fields are designated by the Air Corps as standard homing fields and in the case of a direct homing, the lights observing the distress signal immediately begin homing on the nearest of these standard fields, in the meantime informing the field of the distress signals, and their homing action, so that it will be ready to receive the plane.
In order to make these homing beams more easily visible to the pilots, a standard practice has been developed which has given excellent results. The beam is first exposed as nearly horizontal as possible in the direction of the desired airstrip for a period of 30 seconds. In order to catch the pilot's eye, the beam is then elevated to 45 degrees and depressed again three times quickly without being extinguished. These two procedures are then repeated until the order to douse has been received from the AAOR or the airstrip commander of the homing field.
While the demand for this type of homing has been infrequent due to the fact that usually the searchlights are deployed around an airstrip where a canopy is quicker and more exact in bringing in the plane, it has been called for on 18 occasions. Its importance as a method of homing becomes greater when it is considered that each of these 18 calls came from a plane actually lost or in distress from combat damage and that, except for the availability of this type of homing, these particular aircraft had little or no chance of finding a safe landing place.
Plots send from SCR-268s to flight control and there used to vector planes in to the field have also been used as a homing device. Occasionally when heavy hostile air activity makes the use of even beacons dangerous, this method has proved the only one available. This proved particularly valuable on the night of 23 December 1944 at Airstrip A-82 when a plane returning to base, through error in using the field's homing vector, began to fly directly away from the strip. Personnel at the SCR-268s who, through the searchlight operations officer regularly work in close liaison with the airstrip, immediately noted the error in the plane's course and sent plots to flight control which enabled the officials there to correct the course of the plane and bring it in safely. The plane, a P-61 night fighter, had so little gasoline with which to continue its efforts to return to base that it ran out of fuel on the landing runway.
Low-hanging fog and haze which have frequently closed in on strips on the Continent while planes are still airborne sometimes are so heavy that even canopies and beacons cannot illuminate the field sufficiently to make landing possible and the regular airstrip runway lights are entirely invisible. In such cases lights of the 225th are prepared to illuminate the runway itself by having one of the lights at the end of the runway shine directly down the runway. When doing this, care must be taken that the light selected for the illumination be the one at the end of the strip from which the plane will come in to land so that the pilot will not be blinded. This procedure is used not only on foggy nights but during daylight hours when heavy fog or ground haze have closed in suddenly. Several aircraft have been brought in safely during daylight hours by this method. On the night of 15 September 1944 at Airstrip A-33 three planes returning to base after a heavy fog had set in made three unsuccessful attempts to land and their pilots were prepared to bail out when the flight controller called on newly arrived lights of the 225th for assistance. The strip was illuminated from the approach end of the field and all three planes landed safely. Captain Strickland telephoned profuse thanks to the searchlight officer for this timely aid in saving three valuable planes.
MISCELLANEOUS USES OF SEARCHLIGHTS
Searchlights are prepared to give airstrips, weather stations, and automatic weapons units accurate and almost instantaneous data on ceiling heights during the hours of darkness. This information is made available by having one light expose its beam perpendicularly. A second beam then forms an intersection at the cloud base and from previously prepared angle charts, the ceiling height is immediately available.
Illumination of crashed aircraft
Recently, one of the 225th's lights was put to a valuable emergency use when a plane crashed at Airstrip A-64 while attempting a take-off during the hours of darkness. The crash occurred only about 100 yards from a searchlight section and the light immediately turned its beam on the wreckage, furnishing illumination which made it possible to rescue the crew without delay.
Illumination for night ground work and loading and unloading of supplies
Searchlights of the 225th have frequently been called upon by airstrips around which they were deployed to furnish nighttime illumination to permit ground crews to complete emergency work at airstrips and give light by which supplies might be loaded and unloaded from cargo planes.
Check of aircraft's landing gear
On one occasion a pilot coming in for a landing reported that he was not certain whether he had been able to lower his landing gear. A quick illumination by the lights around the strip revealed that the landing gear had been lowered and the plane was able to come in.
MISCELLANEOUS USES OF SCR-268s
Warning against intruders
A number of airstrips have placed great reliance and dependence on the searchlights in tandem with the SCR-268 radar to give warning in case intruders seek to follow friendly aircraft into base. Intruders have, on a number of occasions, made such attempts and it is standard practice on such occasions to douse all sources of ground illumination and to make an effort to engage the intruders with the lights. Usually, if the intruder has not come within searchlight range, he will reverse course and leave the area as soon as the dousing of the canopy leads him to believe that his presence has been discovered. No intruder which has been engaged by the lights has made a further attempt to approach the defended area and on all the airstrips defended by units of the 225th, no intruder has pressed home an attack on the defended airstrip.
Vectoring night fighters
The practice of using SCR-268s to vector night fighters has employed frequently by both the 422nd and 425th Night Fighter Squadrons. When the 268s pick up a target whose conduct is suspicious but which does not come within searchlight range, flight control is notified of the approximate position of the suspected hostile and, if the flight control officer thinks it advisable, one or more night fighters is scrambled. The radars then send continuous data to flight control by which the flight control officer directs the night fighter toward the suspected hostile until it is able to make a contact with its own (airborne interception) radar. In all cases where this method has been used the suspected hostiles have been driven from the area. Although no definite kills have been reported from such vectored flights, the night fighters have been able to engage the enemy aircraft on at least two occasions.
Checking IFF on friendly planes
Airstrip A-64 frequently uses the SCR-268s to check the IFF on planes leaving the field. As a flight leaves the field, each plane circles individually, transmitting IFF. The radars check the planes one by one and the aircraft are not permitted to leave the area until it has been confirmed that their IFF signal has been received. This practice has materially reduced the number of planes picked up by radar not showing IFF in this area.
COMMUNICATIONS AND OPERATIONS ROOMS
It has been found that maximum efficiency in searchlight defense around airstrips is obtained when the AAOR is located in the flight control room. This location reduces the problems of liaison and greatly reduces delays in passing information from the lights and radars to Air Corps officers and information and orders from the Flight Controller to the searchlight sections. A separate searchlight plotting board is established in this room on which data received from the SCR-268s are translated from polar to grid coordinates for the use of Air Corps, automatic weapons, and searchlight controllers. Two plotters are used for this purpose.
The searchlight platoon's hot loop is terminated at the platoon command post (CP) and from this point a line is run direct to the AAOR. A second administrative line is also run from the platoon CP to the AAOR and the hot loop can be transferred to this line immediately in case of failure in the first line. Data lines are run directly from the radars to the AAOR.
An amplifier unit is connected on to the platoon hot loop so that the searchlight operations officer can hear all information from the sections without the use of a telephone or head and chest set and is this available for constant and immediate liaison with automatic weapons and Air Corps units.
If it is impossible to locate the AAOR in the same room with flight control, certain additions and modifications are necessary. A line is run from the searchlight duty officer to the flight control officer. A second line is run to flight control on which data received from the SCR-268s is reread to flight control where it is available to the flight control officer. If the searchlights are working with night fighters, a radio transmitter is placed in the AAOR by the Air Corps and in case it is desired to vector night fighters toward hostile planes the flight control officer comes to the AAOR and reads vectors over the transmitter from the data appearing on the searchlight plotting board.
COOPERATION WITH AUTOMATIC WEAPONS
For best results in cooperations with automatic weapons units for illumination of high-speed, low-flying targets, two or more batteries of searchlights should be deployed from around a point objective with a grid spacing of from 2,000 to 3,000 yards depending on terrain and atmospheric conditions. Where not enough searchlights are available for this deployment, as was the case in this battalion, a battery defense of a point objective may be better accomplished using an alternate method employing two concentric circles of lights and radars. The inner ring of lights is positioned at 1,500 yards distance from the objective and the outer at 3,200 yards. Each ring consists of six lights spaced either 1,500 or 3,200 yards apart. In locating SCR-268s for illumination of low-flying planes, extreme care had to be taken to avoid mask and still have the necessary screening from fixed echoes. The angle of elevation of antennas should be 150 mils and the sector of search 90 degrees or less in surveillance work against low-flying planes for satisfactory results.
The spread beam has been found to be of value only in assisting in initial pick-ups. If the radar-controlled lights fail to illuminate an incoming plane, the nearest light to the plane when it passes the outer ring of lights goes into action with spread beam in the general direction of the plane. The other lights watch for the plane's silhouette against this spread beam and pick it up with pencil beams. When the pick-up is made, the spread beam changes to pencil beam. We have found in this theater that when spread beams are exposed on a plane, so many moisture and other suspended particles in the air are illuminated that neither the searchlight nor gun crew personnel can see the target through them. This has even been found to be true on bright, moonlit nights when the enemy plane could be seen well enough to be identified without the use of lights.