Monday, October 22, 2007

 

Steve's "Otter Of The Week"!......by Karl E. Hayes

The old Otter has proven through "longevity" to have a very robust airframe and systems. It is, though, still a "mechanical entity", and failures occur, although failures such as the one suffered by the following Otter are rare.

All information is from Karl Hayes' "masterful" CD entitled:

De Havilland Canada
DHC-3 OTTER
A HISTORY

CONTACT KARL, CD PRICING and ORDERING INFO - De Havilland DHC-3 OTTER - A HISTORY by Karl E. Hayes
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Otter 12

Otter 12 was delivered to the RCAF with serial 3666 on 31st March 1953. Prior to delivery, it had carried an AB code for publicity purposes with DHC. After delivery, it was assigned to the Goose Bay, Labrador Station Flight, with code QD. The historical records of the Flight document its activities at Goose, which during the 1950s was also a USAF base. In October 1952 the 59th Fighter Interceptor Squadron had moved in, initially equipped with the F-94 Starfire, later with the F-89 Scorpion starting in 1955 and progressing to the F-102A Delta Dagger in 1960. Also based at Goose was the 59th Search & Rescue Unit, with Grumman SA-16 Albatross aircraft.

Otter 3666 was the only RCAF Otter based at Goose and it served the Station's needs for three years serving alongside a C-47. It provided transport to outlying radar sites and a platform for parachute jumps. It was active in the rescue role and flew many medevacs. It flew on wheel-skis from the base in winter, and on floats from a nearby lake during the summer. A lengthy medevac is recorded on 10th December 1953. The Otter flew 800 miles northwest of Goose to Povungnituk on the north-eastern shore of Hudson Bay. The patient was an Eskimo woman and her critically ill child. Having taken off from Goose, the Otter refuelled at Fort Chimo, Quebec, arrived at Povungnituk that afternoon and took off with the patient to return to Goose. As darkness fell on the way back, and with a blizzard approaching, Flight Lieutenant Turtle set the Otter down on a lake and spent the night with his patients in a temperature of -30C. They took off early the next morning but developed an oil leak en route. Despite oil streaming across the windshield, reducing visibility, the pilot managed to nurse the Otter back to Goose. On 25th January 1954, 3666 was involved in another medevac, from Goose to St.Anthony.

Although there were no other RCAF Otters based at Goose at that time, 3666 often had the company of visiting Otters from 408 Squadron, temporarily deployed to Goose to assist in the squadron's mapping and surveying tasks. On 21st March 1954, a 408 Squadron Otter came down on a frozen lake while flying from Goose Bay due to engine failure. A USAF F-94 Starfire was despatched to search but could not locate the downed Otter. A USAF Albatross of the 59th Search & Rescue Unit eventually located the Otter on its radar and dropped supplies to the downed crew. The Goose Bay SAR RCAF C-47 took off for the scene next morning, arriving at first light. The three crew on the stranded Otter had just got up after spending a bitterly cold night in their aircraft. The tail section of the Otter had collapsed during the forced landing on the lake. A week later the C-47 flew in the repair party. 408 Squadron Otters continued to visit Goose throughout the summer, with 3661, 3678 and 3679 present during June 1954. On 15th August '54 one of the 408 Squadron Otters flew the Duke of Edinburgh from Goose to a fishing camp at Eagle River.

On 13/14th September '54 3666 as well as the based C-47 serial 994 were involved in a search for a missing Bell 47 CF-HND. 3666 was also engaged in many more medevacs, bringing ill and injured persons from the bush to Goose. On 28th September 1955 the Otter on floats suffered an engine failure and was forced down at Northwest River. It suffered the ignominy of being towed back to Goose Bay by a USAF tug. On 6th March 1956, 3666 flew in company with a USAF helicopter to Sabre Lake, to retrieve an engine from a downed USAF jet. On 17th March 1956 it was engaged in parachute jumps at Salt Pond. Sadly, its days were numbered at this stage, for it was to crash near Goose Bay on 10th April 1956.

A few days earlier, the port inner trailing flap had been damaged and a new flap installed. The flight on 10th April '56 was an airtest for the installation. There were three crew on board and weather conditions were good, with broken cloud at two thousand feet and overcast at eight thousand. Visibility was 15 miles in light snow, with an occasional snow shower reducing visibility to half a mile. The Otter was delayed after start up because of such a snow shower and did not receive take-off clearance until visibility improved above VFR minima of three miles. The wheel-ski equipped Otter took off from runway 09 at Goose that afternoon. The take-off was normal and 3666 continued in a straight climb, followed by a slow turn to port. About six miles north of the airport, the Otter broke up in flight and plunged to the ground, sadly killing all three on board. The port wing had broken off and became wrapped around the fuselage, severing the tail assembly.

As the accident was very similar to that which befell a US Army Otter (number 92) two months earlier, a full investigation was launched into both accidents, the cause being traced to a defective flap mechanism. As the report summarised: “A piece of metal swarf had lodged under the ball of the flap hydraulic ratchet valve, holding it open. When the flaps were selected up, the ratchet valve being jammed permitted airloads to collapse the flaps in approximately three seconds, causing a violent trim change which was beyond the pilot's ability to control”.

- by Karl E. Hayes
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"OUCH"! Yes, good thing these types of failures are rare on any aircraft.

CONTACT KARL, CD PRICING and ORDERING INFO - De Havilland DHC-3 OTTER - A HISTORY by Karl E. Hayes

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