16 Radio Unit - Eastern Passage, NS.

1945 - Appendix "A" - National Archives of Canada

MEMORANDUM

No. 16 Radio Unit,
Eastern Passage, NS.,
16th March, 1945.

Our file S-4-1

Confidential

Commanding Officer,
RCAF Station,
Dartmouth.

Controlled Approach System

Following is a brief sketch of the development of the m/n system by this unit:-

Early results from the GCI equipment at No. 16 Radio Unit in picking up surface vessels gave indication that it might be possible to successfully control low-flying aircraft and bring them in onto the aerodrome. Arrangements were accordingly made with the Hurricane Squadron and on March 21st, 1944, two aircraft were sent out twelve miles, brought down first to 500 feet than to 350 feet and steered directly over the runway.

It was felt that if aircraft could be brought down to this level and steered in from over the sea, it might enable us to save any aircraft that might be caught up in the overcast. The pilots of the squadron were very enthusiastic in carrying out this exercise as it not only gave them practice in precision flying but also made them feel that there was a god chance of their getting in if they were ever shut out by a low ceiling. The aerodrome is so placed that aircraft may be brought in from the sea on 02 and 34 runways at 350 feet (sea level) with safety. This was the start of our Controlled Approach System, which was continually being improved and was finally developed to a degree where the procedure, though very simple, completely satisfied the pilots.

W/C Davis (Wing Commander Flying, Dartmouth, at the time) was most interested in this work and he took part in many Controlled Approaches run with BR aircraft with great success, doing many of them under the hood. It was found easier to control large aircraft owing to the response received on our equipment.

The main object in developing this procedure was the fact that we felt we had something that would be of great advantage to any aircraft that might be in distress and shut out by a low ceiling, especially due to the fact that aircraft required nothing more than R/T Communications in order to be directed to the aerodrome. At first it was only thought that it would be possible to direct the aircraft over the aerodrome, but after having more practice in doing the work we found that it was possible to bring them in line with the runway and not more than 1/4 miles from either side, and that we could call the range of the aircraft to within 2 1/2 miles of the runway.

Feeling that we had gone as far as possible with the equipment at our disposal, we decided that if we had mobile radar equipment that could be located on the aerodrome, we felt that we stood a very good chance of being able to follow aircraft right to the point where they landed. With this in mid we secured a VHF truck and had the ASD equipment installed. We found that although we could see the aircraft right on the runways, the picture shown on the scope was not displayed in such a manner as to be suitable for controlling aircraft travelling at a speed where accurate steers must be given quickly. About this time we were asked to co-operate with theArmy which had a GL set-up located on a hill across from the aerodrome. It was a very poor site and the results from it were accordingly poor as the aircraft were continualy being lost by the army operators. This was a great disappointment to us as we had expected rather good results.

Having read in "Radar" magazine about ASG equipment, we felt that if we could obtain this set and install it in our VHF truck, we might be able to further develop our system. Much difficulty was experienced at this time, partly due to the fact that our technical officer, F/L PF Peter, who have been interested in this work, was posted in September and it proved necessary to obtain help from personnel not particularly interested in the project. Also, there was a shortage of ASG equipment and we could do nothing but wait until a set became available.

We at last obtained the ASG equipment and after much delay had it installed in our VHF truck and a power plant built into the trailer. However it was a slow process modifing the equipment in order that it might be used to bring in aircraft. F/L Peter was posted back to this unit in January and with his assistance we finally began to get things moving. We tested various sites around the aerodrome and found that the triangle in the centre of the runways was the likeliest spot in which to locate. In this location it was found possible to cover runways, 11, 02, 34 and 29.

The first actual tests were conducted on March 5th with two Hurricane aircraft on runway 29. They were controlled from No. 16 Radio Unit to within seven miles of the aerodrome then taken over on the ASG set. The first run was slightly to starboard, the other two dead on. On March 8th, two Hurricanes were again employed and this time four approaches were attempted and successfully completed. On March 9th, eight controlled approaches were made and seven of them dead on; the eighth had to be discontinued when two miles out, due to another aircraft's landing at that time. On March 11th, three runs were made, using one Hurricane, and all were successful. On March 12th, five runs were made, two were slightly to starboard due to trouble being experienced with the equipment, the remain three dead on the runway.

We have again been requested to co-operate with the Army whose G.L set, equipped with a fully Automatic Plotter, has been set up on another site. On March 8th, an attempt was made to control an aircraft, but had to be cancelled when R/T communications failed. However, it is thought that a successful trial will be conducted soon, as the only requirements are that we bring in the aircraft over the aerodrome at three hundred feet. Insofar as our GCA system is concerned, this will be of no help, as we can already do as much with the GCI equipment at this unit, the GL set having a maximum range of 2000 yards. However, if this equipment were modified somewhat and placed at a distance of abut 1/2 mile beyond the end of one particular runway, a blind landing system might be put into effect, providing that the proper technical help were given.

We feel that the ASG equipment used in conjunction with the facilities of No. 16 Radio Unit would be of great assistance to any aircraft attempting to land on the aerodrome in poor weather, and further, that if we could have the proper technical help, now lost as the result of F/L Peter's again having been posted, and the necessary authority, the system as it now stands could be perfected and developed into an efficient blind landing system.

We have been handicapped in the past in carrying out these controlled approaches by the firing of the anti-aircraft battery in the vicinity, which considerable restricted the full use of the runways. However, we are of the hope that this difficulty will be eliminated shortly.

The writer feels that with constant practice on the ASG equipment, with possibly a few minor modifications, astonishing results are possible, as it must be borne in mind that everything accomplished to date has been achieved in spite of the fact that the ASG equipment has never been used by this unit for this purpose.

(JAV MacRobert) S/L,
OC No. 16 Radio Unit.