by Gordon Andreassend
The first recorded aerial photographic flying in Hong Kong took place in 1924. We are indebted to Group Capt. G.E. Livock for his description of these flights in his book, To the Ends of the Air Livock gives details of the air survey flights which were carried out by three Fairey IIID seaplanes, piloted by an RAF unit from the seaplane carrier, HMS Pegasus. The aircraft were lowered to the water for take-off, and hoisted back onto the ship when their flights were completed.
In March, 1924 the ship departed from England with the task to carry out photographic surveys of Singapore Island and southern Johore, then cover Hong Kong with similar photography.
On 3 November, 1924, the Pegasus steamed to her anchorage in Hong Kong harbour. As Livock recounts - “We all stood spellbound by the beauty of the place. The harbour crowded with liners and cargo ships, warships and Chinese junks was in a permanent state of activity and movement.”
On 4 November Livock made his first half hour flight over Hong Kong, and in near perfect weather they started about 3 weeks of aerial photography, when they “romped through the air survey without any difficulty”. He notes that, “Hong Kong harbour itself is not an ideal place for seaplane flying on account of the dense water traffic, so the ship moved to Tolo Harbour. This was ideal for our purpose and was also more convenient for covering the Leased Territory, which lay on the northern boundary of the Hong Kong area.”
Unfortunately there are no details given regarding the camera equipment used, but the images were taken on film (not glass plates), and Hong Kong, Kowloon and the New Territories were covered completely. The stereo photography obtained in Hong Kong was later used for UK military mapping.
A new 1:20 000 map series (GSGS 3868) was issued in 1929. This mapping was one of the first to be produced by photogrammetry in the UK.
Regrettably all the Hong Kong negatives and the photography that had been taken were lost in the UK during WW II, and it was not until about 1980 some 100 prints of the photography were discovered in the archives of the Hong Kong University. It is quite amazing that the prints remained safely stored in the University throughout the Japanese occupation.
They have been copied to the cartographic records section of the Survey and Mapping Office, and have been used extensively for mapping research.
That 1924/25 RAF photography was the first and last aerial survey photography carried out for nearly 40 years. The only images from the air that we now have records of during the 1930s, up to the start of the Pacific War, are isolated oblique photography probably taken from private aircraft operating from Kai Tak, or visiting RAF aircraft. No doubt it was hand-held photography taken using small format cameras from open cockpit aircraft.
During the war aerial photography was taken from US Air Force bombers during raids on Hong Kong, and some from accompanying fighter aircraft. Most of this photography was used for record and reconnaissance purposes, and these photographs are now available from US archives.
Immediately post war the RAF returned to Hong Kong, and oblique aerial photography was taken on a regular basis for record purposes. All that photography was handed over to the Hong Kong Government when the RAF left Hong Kong in 1997, and is now held in the Survey and Mapping Office’s archives.
More hand held aerial photographs were taken from private aircraft post war, and in 1958 the photographers from the then Survey Office took mainly 35mm photography from the air, using HKAAF helicopters. In the 1960’s a decision was made to bring in a consultant company to map Hong Kong using aerial photography. The contract to do this work was given to an experienced UK company, Hunting Surveys Limited, and they positioned an aircraft in Hong Kong in January 1963 to start this project.
The aircraft leased by Huntings to operate in Hong Kong, a Cessna 310G, was flown single-handed from Kuala Lumpur via Saigon, arriving on the afternoon of January 21. Hunting’s navigator had flown in on the same morning, together with Wild RC8 camera from Singapore. The camera was quickly installed in the aircraft, and all was ready by the afternoon of January 22 for a proving flight to be carried out. A short run of film was taken, and was processed in a darkroom at the Kai Tak RAF base that evening. The team was pleased that photographs of useable quality had been obtained.
Coverage of the most important areas commenced on January 24, and with the exception of a few rest days and non-operational days the entire coverage of all areas to be mapped was completed by February 28. The specified mapping scales of 1:600 for the urban areas, and 1:1200 for areas in the New Territories (NT) meant that two flying heights were requires. Urban areas were flown at 2,700 feet to enable plotting of 5 foot contours, and in the N.T. a flying height of 3,900 feet met all specifications of plotting 10 foot contours up to the 600 foot contour.
The RC8 Aviogon 152.4mm (6 inch) lens was used to provide 230x230mm (9x9 inch) format images. The film used was Ilford Hyperpan using a X2 minus blue filter, with shutter speeds of 1/600th or 1/700th of a second at f8.
The Cessna 310G aircraft had been modified for aerial survey work at the time it was constructed, and its excellent performance assisted considerably in completing the project under the flight conditions experienced in Hong Kong.
Each run of photography was checked on a daily basis to ensure that the require overlap areas were all covered. With the full coverage of stereo photography ensured, the Hunting team was able to return to the UK with all the required data, and the aircraft was flown back to Kuala Lumpur.
The next task was to supply the staff of the Crown Lands & Survey Office with overlapping pairs of photographs to be used in providing control points. This work was carried out by Survey Office staff over the next two to three years, and it took five years, from 1963 to 1968 to complete all the plotting.
This project commenced under the supervision of Mr Reg. Giles, the head of the Survey Office, and on his retirement continued under Mr John Cooper.
Huntings representative was Mr Harry Dawe, who supervised the photographic operations in 1963, and oversaw much of the plotting of the map sheets in the UK.
Altogether, some ...(SMO records)... photographic images were obtained from the 1963 aerial survey project, and they are all of an exceptionally high quality. The film is now kept in the SMO archives, and all images have been transferred to the digital database.
The Development of Aerial Survey Flying in the CL&SO
The development of aerial surveying in Hong Kong owes much to two of the earlier heads of the Survey Office – Reg. Giles and John Cooper.
Under their guidance the comprehensive mapping of Hong Kong was introduced in the early 1960s. Details of the Hunting Survey contract are given in the preceding chapter. It was through this association with Huntings that the opportunity arose for the Survey Office to develop its own aerial photographic capability, and in 1965 another important catalyst in this development came upon the scene.
The “catalyst” was none other than the ‘father’ of aerial survey and photogrammetry in Hong Kong, Roy Davey. Roy was a South African Land Surveyor who had completed the photogrammetric course at the ITC at Delft, in Holland. He was most enthusiastic in his drive to bring photogrammetry into the Survey Office.
In 1966 Huntings made an offer to CL&SO that the Survey Office could take on loan an old WILD RC5A camera, to be used in trials of taking aerial photography in Hong Kong. The Auxiliary Air Force agreed that they could supply a fixed-wing aircraft, an Auster, for this purpose, and the die was cast. Roy ensured the Hunting’s offer was accepted, and supervised the installation of the camera mount into the HKAAF Auster, HKG-9. Once this was completed, Roy carried out a number of proving flights in 1967.
However, in 1968 Roy decided to return to his native South Africa, and the search was on for someone to replace him. This is where Gordon Andreassend came into the picture. He was a land surveyor working in the Roads and Drains office, with experience in flying and a longtime interest in aviation. He put in many hours during 1968 in learning all that Roy could teach him.
Training in the use of the camera was difficult in that it had to be carried out on the ground. As the Auster could only carry one passenger once the camera was installed, it was not possible to carry out any in-flight instruction. So, with two feet on the ground, Roy took Gordon through all the airborne drills of running the camera.
Before Roy left, they made several attempts for Roy to fly a sortie. He would then return and let Gordon fly the same sortie. However, because of bad weather, problems with the aircraft and other setbacks, this never happened.
A week or so after Roy’s departure Gordon managed to get airborne and ran through all the camera operations with film in the camera. To his relief, the results were acceptable.
Initially Gordon flew with Flt. Lt. Denis Moyes, the RAF instructor attached to the Auxiliaries. He was very good in meeting air survey requirements, despite the lack of experience they both had in this field.
He did test Gordon however, on an Auster flight where Gordon was facing the direction of flight. When operating the camera, the camera operator had to sit facing the tail of the aircraft. At the time they were approaching Kai Tak to land, when Denis threw one of those flying Instructor’s “wobblies”. “Hey, what do I do now! ? I can’t remember how to land this thing,”etc. Gordon passed this test as he had enough flying experience to take the controls and suggest that Denis could sit back while he landed. Denis laughed, said “I have control,” and took HKG-9 into Kai Tak.
The CL&SO Air Survey Team
By 1968 it was considered that the camera operation was going well, and a regular air survey team was established. Peter Moore, a volunteer Auxiliary Air Force pilot agreed to fly HKG-9 on photographic missions, while Gordon manned the camera. This was quite a good arrangement, as Peter was an Estate Surveyor, working in the New Territories at that time. Also, Gordon had transferred from his Land Surveyor post to fill the fill a recently created post of Cartographer in the headquarters of the Survey Office. He and Peter were both staff of the Crown Lands & Survey Office (CL&SO) and had little difficulty to take to the air at any time the weather was suitable. So the CL&SO air survey team was formed.
The two surveyors worked well in their air survey role. The cassette for the roll of air survey film was loaded in the darkroom of the CL&SO HQ in the Central Government Offices, and Gordon carried it across to the HKAAF base at Kai Tak, where Peter would have HKG-9 ready for flight. The camera had been mounted in the rear of the plane, and once the cassette had been installed, they were ready to take to the air. After the mission was completed the cassette was removed, and returned to the CL&SO reprographic section for development and printing. The format of the photography was 7 inches square, and the rolls of film were 250 ft. in length.
Pre-flight discussion of the day’s programme was carried out at the aircraft, and essential details such as flying heights and run in approaches were settled. Once they were strapped-in the engine was started and a fairly long taxi run was usually required to get HKG-9 lined up for take-off in between departing jets and other commercial aircraft.
Communication between the pilot and the camera operator navigator is most important in aerial survey flying. The Auster was a noisy aircraft, especially as it was flown without doors. However, the requirement to wear a throat microphone and a cloth cap that had earphones that would fit over your ears, solved most of the noise problem, and speech between the navigator and pilot was very clear.
The HKG-9 team soon commenced using an inflight system when camera operation along pre-determined flight lines was required. Because the camera operator had to sit with his back to the engine, it was decided to use only port and starboard when referring to direction. The fact that pilot and navigator were facing opposite directions meant that the use of left or right could be confusing when making course corrections.
The navigation of the aircraft could only be carried out by the camera operator. The pilot could not see much of the ground in front of the nose of the aircraft, and he was concentrating on the instruments to ensure that the correct height was maintained, the attitude was straight and level, and a constant speed was maintained. The navigator would lean out the open door to ensure that the heading was along the desired flight line, and give course corrections, in estimated degrees, in a ‘port’ or ‘starboard’ direction. As the aircraft approached the point where camera operation would start, the navigator would say that the camera would commence in say, five seconds, and immediately stat to count those seconds down - "five and four and" etc., until at zero, he would wind on the first exposure to be taken on the flight line. The camera had been converted for manual use, so a handle had to be turned a complete revolution to advance the film in the camera, and have it ready for the next exposure. The time between each exposure to obtain 60% overlap was pre-determined based on airspeed and altitude, and the time between each exposure would be counted aloud so that the pilot knew when he should keep the aircraft as steady as possible at the time of exposure. The navigator’s patter would go something like this :-“ Twelve second intervals-now! and 2 and 3” etc. up to 12, when the process would start again until the flight line had been completed. There was no time for the camera operator to refer to a clock, so this countdown method was used, and proved to be very reliable. Obtaining 60% to 65% overlap of the photographs in each run was average. On longer flight lines, the camera operator had to quickly revert to his navigator role during the countdown in order to give a quick course correction, while looking out the door. This could possibly go - "five and six… 4 degrees port- eight and nine" etc.
All this may sound very primitive, but it worked, and results were obtained that were good enough for photogrammetric plotting.
Most of the aerial survey photography work involving Peter and Gordon was carried out in 1969, and the last eight months found them both working in the New Territories Administration, so it was even easier for them to arrange their air survey flying. Gordon was scheduled to go on leave at the end of 1969, and he arranged for two land surveyors, Mike Durant, and Terry Bateman to train as camera operators.
He had arranged to go to France during his leave to study photogrammetry at the IGN, the French organisation responsible for the country’s mapping. Such courses were sponsored by the French government as part of their overseas aid programme.
Towards the end of his training he received some bad news from Hong Kong. Auster HKG-9 had crashed into the harbour when taking off from Kai Tak, and Peter Moore had been killed. The air survey camera body had been fitted in the plane and was damaged beyond repair.
This was a major tragedy, in all respects, and meant that the CL&SO was once again without any aerial survey capability. In autumn 1970 Gordon returned to Hong Kong from France via the UK, and arrangements were made for him to visit the UK firm, Fairey Aviation, where they had adapted a helicopter to carry an air survey camera. A special mount had been developed to supress the vibrations that are very high in helicopters, and it was worth looking at what they had achieved. The thought in Hong Kong was that the HKAAF could use one of its Alouette helicopters to carry a new air survey camera. For many reasons this idea was dropped.
A New Camera, and a New Twin-engined Aircraft
The loss of HKG-9 and the writing off of two other Austers in 1971 meant that the HKAAF had no fixed-wing aircraft, and urgent discussions were held that year that resulted in orders being placed for a Britten-Norman Islander aircraft that would have the capability of carrying a Wild RC10 aerial camera. Both the Islander and the RC10 arrived in March, 1972.
The Islander had been converted in Singapore, with an opening cut in the fuselage, and a frame fitted in the floor to carry the air survey mount. The Britten Norman sales representative, John Pereira, and John Shawcross, the Adjutant of the Auxiliary Air Force flew the aircraft to Hong Kong from Singapore via Kota Kinabalu and Manila, arriving on March 9, 1972, and it was registered as HKG-7.
The RC10 camera arrived from Switzerland two days later together with a technician from Wild, who installed the base mount for the camera, and checked all was functioning well. Another Wild specialist in aerial camera operation, Manfred Duddek, was also there to supervise the installation, and to provide initial training to the pilots who would fly the air survey sorties, and to instruct the CL&SO navigator/camera operator. At that time, Gordon Andreassend was in the post of SLS/Control (now Geodetic), and as he had earlier air survey experience, and had been involved in the purchase of the RC10, it was decided that he would also take on the work of camera operator, until a permanent post of Land Surveyor /Air Survey was created.
With the camera operational, and ground instruction completed, Manfred and Gordon took to the air to make some trial flights and to expose a roll of Kodak film. Each roll is 250 feet in length, and the format of each exposure is 9 inches square. All progressed well, and soon the air survey team was working on a regular basis. John Shawcross flew most of the early air survey runs, with the RAF Fixed Wing instructors, such as Peter Adair and Bob Lee also taking on this work. Senior RHKAAF pilots, such as Mike Wightman also soon adapted to air survey flying and assisted in training some of the Auxiliary pilots to fly these air survey sorties. Gordon recalls his longest flight on a perfect flying day, with Mike Wightman at the controls. The Islander was airborne for almost eight hours, and oh the relief when back on the ground!
Requests for aerial survey work came in from many departments, but it was not possible to produce mapping in Hong Kong, as the Photogrammetric Unit was still at the planning stage. However, several sheets of topographical mapping were carried out overseas, using RC10 photography and ground control from the Survey Office. In 1973 the first roll of colour film was taken, though this had to be sent to Kodak in Australia for processing. The results were good, and several images were used in the Hong Kong Yearbook.
Progress on establishing the Photogrammetry Unit was moving ahead, and the Reprographic Section was expanded to deal with more of the aerial photography film processing work. Then in 1975, there was a major breakthrough when the Land Surveyor/Air Survey post was created, and Brian Smith agreed to move into that post.
Air survey was about to take off under the professional control of a land surveyor, solely administering aerial photography, in a post dedicated to aerial surveying work.