Ansett-ANA Flight 325
Encyclopedia
On 30 November 1961 a Vickers Viscount
aircraft departed from Sydney
, Australia
late in the afternoon for a flight of 128 nautical miles (236 km) to Canberra
. There were thunderstorm
s to the north and south of the airport. From about 9 minutes after takeoff the crew of Ansett-ANA Flight 325 did not respond to radio calls. The Flight did not arrive at its destination and authorities received no report of a crash. Throughout the night no-one knew the fate of the aircraft or its occupants.
The next day wreckage and a fuel slick
were found on the surface of Botany Bay
. The aircraft had been drawn into a thunderstorm and subjected to extreme turbulence. It had broken up and crashed into Botany Bay, less than 3 miles from where it took off. All fifteen occupants died.
on runway 07 at 7:17 pm local time for a scheduled passenger flight to Canberra. On board were two pilots, two air hostesses
and eleven passengers.
Around the time of takeoff there was a severe thunderstorm with very heavy rain to the south of the airport and another to the north. There was cloud about 800 feet (244 m) above Sydney airport but no thunderstorm activity. Flight 325 was observed to enter cloud shortly after take off. Five other aircraft took off while this meteorological situation existed.
Flight 325 was directed to take-off and continue heading east towards the ocean until reaching an altitude of 3,000 feet (915 m), turn around and fly west to a radio navigation aid
6½ miles (10.5 km) west of the airport and then turn south-west for Canberra. The crew were to ensure they passed over the airport no lower than 5,000 feet (1 525 m).
Five minutes after takeoff the crew advised they had reached 6,000 feet (1 830 m). About 3½ minutes later, Sydney air traffic control
called Flight 325 with a routine request for information but received no reply. No further radio communication was received from Flight 325 so when it did not arrive at Canberra airport authorities knew it had suffered an accident. An air search of the route to Canberra was planned to commence at dawn
.
Approximately 9 minutes after takeoff the right wingtip had been torn away and the aircraft had crashed into Botany Bay. The rain, thunder and lightning associated with the thunderstorm over Botany Bay had been so intense that no-one saw the aircraft or observed anything crash into the water. Accident Investigator Frank Yeend wrote "The weather was so bad that this aircraft crashed in the middle of a major city without anybody having seen it or heard anything that would give cause to alarm."
the next morning searchers on Botany Bay found some of the upholstery
from one of the pilots' seats and other floating wreckage. Searchers on the beach in the north-east of Botany Bay, near Bunnerong Power Station, found some cabin furnishings and body parts. The right wingtip was found protruding above the surface of shallow water near Kurnell. Later in the day Police and Navy
divers investigated a large fuel slick in the centre of Botany Bay and discovered the scattered wreckage of VH-TVC in 25 feet (8 m) of water. The aircraft had crashed 2.8 statute miles (4.5 km) south-east of Sydney airport.
The Royal Australian Navy
sent a team of clearance divers
and HMAS Kimbla, a boom defence vessel, to bring the main wreckage of VH-TVC to the surface. After a week Kimbla was replaced by HMAS Walrus, a smaller workboat from which the Navy divers worked for many weeks, locating and recovering many smaller pieces of wreckage.
The right tailplane
was missing from the main wreckage. Navy divers eventually found the missing parts of the tailplane close to where the right wingtip was found, indicating the right tailplane was torn from the aircraft prior to its impact with the water.
Numerous small items, including many from the number 4 engine
nacelle
, were found on Kurnell peninsular, south of the right wingtip. The wreckage trail was aligned approximately north-south with the main wreckage at the north in Botany Bay; and the smaller, lighter items at the south on Kurnell peninsular.
The aircraft was not equipped with a flight data recorder
or cockpit voice recorder
so it was important that as much as possible of the wreckage should be recovered and examined. The recovery effort continued for 3 months.
It soon became clear that the spar
in the right wing had broken and the wingtip had been torn away by the airstream. The lower boom (or lower flange
) in the wing spar had failed in upward bending at station 323 due to extreme overload. The wing had been overloaded while the aircraft was flying at very high speed, probably in excess of the maximum safe speed of 260 knots indicated airspeed
.
Engineers assisting the accident investigation calculated that for the wing spar to fail in the way it did in VH-TVC would require the aircraft to be flying faster than its maximum speed of 260 knots and, while being subjected to a severe recovery manoeuvre by the crew, to encounter a very strong gust, possibly as much as 100 ft.s-1 (30 m.s-1). At the time of the accident investigation, gusts up to 72 ft.s-1 (22 m.s-1) had been measured inside thunderstorms by suitably equipped research aircraft.
All the wreckage lay in a trail aligned north-south. By making assumptions about the likely terminal velocities
of key pieces of wreckage, accident investigators were able to determine the approximate location, height and speed of the aircraft at the time it broke up. They believed the right wingtip was torn away when the aircraft was south of its intended flight path, heading in a northerly direction, and at a height between 3,500 ft (1 067 m) and 5,500 feet (1 676 m). They believed this occurred at a time when the aircraft should have been at about 9,000 feet (2 743 m), heading west and passing over a radio navigation aid nine miles away. It was necessary for the investigation to find a rational explanation as to why the aircraft was so far from where it should have been.
Accident investigators studied a scientific report titled The Thunderstorm published in the USA in 1949. This report proposed that where two thunderstorms were separated, edge to edge, by less than 6 miles (9.7 km) there was a likelihood of severe turbulence in the clear air between the two. The accident investigators believed it was likely that Flight 325, while flying west between two mature thunderstorms, encountered strong turbulence that caused the crew to lose control and the aircraft to lose a significant amount of height and enter the thunderstorm to the south of the airport. While flying north, possibly in an attempt to escape the thunderstorm, the crew encountered continuing strong turbulence that caused control to be lost again. The aircraft accelerated to its maximum safe speed or faster and while the crew were struggling to regain control the aircraft was suddenly subjected to extreme turbulence that caused the right wing spar to fail.
of the Commonwealth Industrial Court
. The Board first convened on 12 June 1962, sat for 24 days and closed on 27 July 1962.
Investigation of the accident concluded:
The Inquiry gave a strong impetus for greater co-operation between the meteorological service and air traffic control; and for airline aircraft in Australia to be equipped with weather radar to give pilots of these aircraft the ability to avoid hazardous weather. All Australian airliners were required to be equipped with weather radar by 1 June 1963.
on 8 December 1954 and named John Oxley
in honour of an early Australian explorer and surveyor.
VH-TVC was leased to Ansett-ANA on 7 March 1960 and operated with the passenger cabin configured for 48 passengers.
The aircraft made 12,010 flights and flew for 16,946 hours.
Vickers Viscount
The Vickers Viscount was a British medium-range turboprop airliner first flown in 1948 by Vickers-Armstrongs, making it the first such aircraft to enter service in the world...
aircraft departed from Sydney
Sydney
Sydney is the most populous city in Australia and the state capital of New South Wales. Sydney is located on Australia's south-east coast of the Tasman Sea. As of June 2010, the greater metropolitan area had an approximate population of 4.6 million people...
, Australia
Australia
Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...
late in the afternoon for a flight of 128 nautical miles (236 km) to Canberra
Canberra
Canberra is the capital city of Australia. With a population of over 345,000, it is Australia's largest inland city and the eighth-largest city overall. The city is located at the northern end of the Australian Capital Territory , south-west of Sydney, and north-east of Melbourne...
. There were thunderstorm
Thunderstorm
A thunderstorm, also known as an electrical storm, a lightning storm, thundershower or simply a storm is a form of weather characterized by the presence of lightning and its acoustic effect on the Earth's atmosphere known as thunder. The meteorologically assigned cloud type associated with the...
s to the north and south of the airport. From about 9 minutes after takeoff the crew of Ansett-ANA Flight 325 did not respond to radio calls. The Flight did not arrive at its destination and authorities received no report of a crash. Throughout the night no-one knew the fate of the aircraft or its occupants.
The next day wreckage and a fuel slick
Oil spill
An oil spill is the release of a liquid petroleum hydrocarbon into the environment, especially marine areas, due to human activity, and is a form of pollution. The term is mostly used to describe marine oil spills, where oil is released into the ocean or coastal waters...
were found on the surface of Botany Bay
Botany Bay
Botany Bay is a bay in Sydney, New South Wales, a few kilometres south of the Sydney central business district. The Cooks River and the Georges River are the two major tributaries that flow into the bay...
. The aircraft had been drawn into a thunderstorm and subjected to extreme turbulence. It had broken up and crashed into Botany Bay, less than 3 miles from where it took off. All fifteen occupants died.
The flight
Ansett-ANA Flight 325, a Vickers Viscount registered VH-TVC, took off from Sydney airportSydney Airport
Sydney Airport may refer to:* Sydney Airport, also known as Kingsford Smith International Airport, in Sydney, Australia* Sydney/J.A. Douglas McCurdy Airport, in Nova Scotia, Canada...
on runway 07 at 7:17 pm local time for a scheduled passenger flight to Canberra. On board were two pilots, two air hostesses
Flight attendant
Flight attendants or cabin crew are members of an aircrew employed by airlines primarily to ensure the safety and comfort of passengers aboard commercial flights, on select business jet aircraft, and on some military aircraft.-History:The role of a flight attendant derives from that of similar...
and eleven passengers.
Around the time of takeoff there was a severe thunderstorm with very heavy rain to the south of the airport and another to the north. There was cloud about 800 feet (244 m) above Sydney airport but no thunderstorm activity. Flight 325 was observed to enter cloud shortly after take off. Five other aircraft took off while this meteorological situation existed.
Flight 325 was directed to take-off and continue heading east towards the ocean until reaching an altitude of 3,000 feet (915 m), turn around and fly west to a radio navigation aid
Non-directional beacon
A non-directional beacon is a radio transmitter at a known location, used as an aviation or marine navigational aid. As the name implies, the signal transmitted does not include inherent directional information, in contrast to other navigational aids such as low frequency radio range, VHF...
6½ miles (10.5 km) west of the airport and then turn south-west for Canberra. The crew were to ensure they passed over the airport no lower than 5,000 feet (1 525 m).
Five minutes after takeoff the crew advised they had reached 6,000 feet (1 830 m). About 3½ minutes later, Sydney air traffic control
Air traffic control
Air traffic control is a service provided by ground-based controllers who direct aircraft on the ground and in the air. The primary purpose of ATC systems worldwide is to separate aircraft to prevent collisions, to organize and expedite the flow of traffic, and to provide information and other...
called Flight 325 with a routine request for information but received no reply. No further radio communication was received from Flight 325 so when it did not arrive at Canberra airport authorities knew it had suffered an accident. An air search of the route to Canberra was planned to commence at dawn
Dawn
Dawn is the time that marks the beginning of the twilight before sunrise. It is recognized by the presence of weak sunlight, while the sun itself is still below the horizon...
.
Approximately 9 minutes after takeoff the right wingtip had been torn away and the aircraft had crashed into Botany Bay. The rain, thunder and lightning associated with the thunderstorm over Botany Bay had been so intense that no-one saw the aircraft or observed anything crash into the water. Accident Investigator Frank Yeend wrote "The weather was so bad that this aircraft crashed in the middle of a major city without anybody having seen it or heard anything that would give cause to alarm."
Search and recovery
Soon after sunriseSunrise
Sunrise is the instant at which the upper edge of the Sun appears above the horizon in the east. Sunrise should not be confused with dawn, which is the point at which the sky begins to lighten, some time before the sun itself appears, ending twilight...
the next morning searchers on Botany Bay found some of the upholstery
Upholstery
Upholstery is the work of providing furniture, especially seats, with padding, springs, webbing, and fabric or leather covers. The word upholstery comes from the Middle English word upholder, which referred to a tradesman who held up his goods. The term is equally applicable to domestic,...
from one of the pilots' seats and other floating wreckage. Searchers on the beach in the north-east of Botany Bay, near Bunnerong Power Station, found some cabin furnishings and body parts. The right wingtip was found protruding above the surface of shallow water near Kurnell. Later in the day Police and Navy
Royal Australian Navy
The Royal Australian Navy is the naval branch of the Australian Defence Force. Following the Federation of Australia in 1901, the ships and resources of the separate colonial navies were integrated into a national force: the Commonwealth Naval Forces...
divers investigated a large fuel slick in the centre of Botany Bay and discovered the scattered wreckage of VH-TVC in 25 feet (8 m) of water. The aircraft had crashed 2.8 statute miles (4.5 km) south-east of Sydney airport.
The Royal Australian Navy
Royal Australian Navy
The Royal Australian Navy is the naval branch of the Australian Defence Force. Following the Federation of Australia in 1901, the ships and resources of the separate colonial navies were integrated into a national force: the Commonwealth Naval Forces...
sent a team of clearance divers
Clearance Diving Team (RAN)
The Clearance Diving Teams of the Royal Australian Navy also act as commando frogmen: they consist of naval personnel who are qualified in diving, demolitions, underwater repairs, and reconnaissance...
and HMAS Kimbla, a boom defence vessel, to bring the main wreckage of VH-TVC to the surface. After a week Kimbla was replaced by HMAS Walrus, a smaller workboat from which the Navy divers worked for many weeks, locating and recovering many smaller pieces of wreckage.
The right tailplane
Tailplane
A tailplane, also known as horizontal stabilizer , is a small lifting surface located on the tail behind the main lifting surfaces of a fixed-wing aircraft as well as other non-fixed wing aircraft such as helicopters and gyroplanes...
was missing from the main wreckage. Navy divers eventually found the missing parts of the tailplane close to where the right wingtip was found, indicating the right tailplane was torn from the aircraft prior to its impact with the water.
Numerous small items, including many from the number 4 engine
Aircraft engine position number
Aircraft engine position number is a method to identify the location of engines on multi-engined aircraft. Aircraft engines are numbered from left to right from the view of the pilot looking forward.-Twin-engined aircraft:* #1 - port - on the left...
nacelle
Nacelle
The nacelle is a cover housing that holds engines, fuel, or equipment on an aircraft. In some cases—for instance in the typical "Farman" type "pusher" aircraft, or the World War II-era P-38 Lightning—an aircraft's cockpit may also be housed in a nacelle, which essentially fills the...
, were found on Kurnell peninsular, south of the right wingtip. The wreckage trail was aligned approximately north-south with the main wreckage at the north in Botany Bay; and the smaller, lighter items at the south on Kurnell peninsular.
The aircraft was not equipped with a flight data recorder
Flight data recorder
A flight data recorder is an electronic device employed to record any instructions sent to any electronic systems on an aircraft. It is a device used to record specific aircraft performance parameters...
or cockpit voice recorder
Cockpit voice recorder
A cockpit voice recorder , often referred to as a "black box", is a flight recorder used to record the audio environment in the flight deck of an aircraft for the purpose of investigation of accidents and incidents...
so it was important that as much as possible of the wreckage should be recovered and examined. The recovery effort continued for 3 months.
Investigation
As pieces of wreckage from VH-TVC were progressively recovered from Botany Bay they were laid out in a hangar at Sydney airport to allow investigators to search for the cause of the accident. The right tailplane and right wingtip had received almost no damage on impact with the water but the main wreckage in Botany Bay showed extensive disintegration, suggesting a very high speed of impact. No evidence was found of any fault or mechanical failure that might have existed prior to the accident.It soon became clear that the spar
Spar (aviation)
In a fixed-wing aircraft, the spar is often the main structural member of the wing, running spanwise at right angles to the fuselage. The spar carries flight loads and the weight of the wings whilst on the ground...
in the right wing had broken and the wingtip had been torn away by the airstream. The lower boom (or lower flange
I-beam
-beams, also known as H-beams, W-beams , rolled steel joist , or double-T are beams with an - or H-shaped cross-section. The horizontal elements of the "" are flanges, while the vertical element is the web...
) in the wing spar had failed in upward bending at station 323 due to extreme overload. The wing had been overloaded while the aircraft was flying at very high speed, probably in excess of the maximum safe speed of 260 knots indicated airspeed
Indicated airspeed
Indicated airspeed is the airspeed read directly from the airspeed indicator on an aircraft, driven by the pitot-static system. IAS is directly related to calibrated airspeed , which is the IAS corrected for instrument and installation errors....
.
Engineers assisting the accident investigation calculated that for the wing spar to fail in the way it did in VH-TVC would require the aircraft to be flying faster than its maximum speed of 260 knots and, while being subjected to a severe recovery manoeuvre by the crew, to encounter a very strong gust, possibly as much as 100 ft.s-1 (30 m.s-1). At the time of the accident investigation, gusts up to 72 ft.s-1 (22 m.s-1) had been measured inside thunderstorms by suitably equipped research aircraft.
All the wreckage lay in a trail aligned north-south. By making assumptions about the likely terminal velocities
Terminal velocity
In fluid dynamics an object is moving at its terminal velocity if its speed is constant due to the restraining force exerted by the fluid through which it is moving....
of key pieces of wreckage, accident investigators were able to determine the approximate location, height and speed of the aircraft at the time it broke up. They believed the right wingtip was torn away when the aircraft was south of its intended flight path, heading in a northerly direction, and at a height between 3,500 ft (1 067 m) and 5,500 feet (1 676 m). They believed this occurred at a time when the aircraft should have been at about 9,000 feet (2 743 m), heading west and passing over a radio navigation aid nine miles away. It was necessary for the investigation to find a rational explanation as to why the aircraft was so far from where it should have been.
Accident investigators studied a scientific report titled The Thunderstorm published in the USA in 1949. This report proposed that where two thunderstorms were separated, edge to edge, by less than 6 miles (9.7 km) there was a likelihood of severe turbulence in the clear air between the two. The accident investigators believed it was likely that Flight 325, while flying west between two mature thunderstorms, encountered strong turbulence that caused the crew to lose control and the aircraft to lose a significant amount of height and enter the thunderstorm to the south of the airport. While flying north, possibly in an attempt to escape the thunderstorm, the crew encountered continuing strong turbulence that caused control to be lost again. The aircraft accelerated to its maximum safe speed or faster and while the crew were struggling to regain control the aircraft was suddenly subjected to extreme turbulence that caused the right wing spar to fail.
Board of Accident Inquiry
A Board of Accident Inquiry was appointed in 1962 to investigate all aspects of the accident to Flight 325. Chairman of the Board was Mr Justice SpicerJohn Spicer (Australian politician)
Sir John Armstrong Spicer was an Australian lawyer, politician, cabinet minister and judge.Spicer was born in the Melbourne suburb of Prahran, but was taken to England by his family in 1905 and educated at Chelston School, Torquay. His family returned to Australia in 1911 and he attended Hawksburn...
of the Commonwealth Industrial Court
Australian Industrial Relations Commission
The Australian Industrial Relations Commission, or AIRC , was a tribunal with powers under the Workplace Relations Act 1996. It was the central institution of Australian labour law...
. The Board first convened on 12 June 1962, sat for 24 days and closed on 27 July 1962.
Investigation of the accident concluded:
The cause of the accident was the failure in flight of the starboard outer wing in upward bending due to tensile overloading of the lower spar boom at station 323, probably induced by a combination of manoeuvre and gust loading when the speed of the aircraft was in excess of 260 knots. The circumstances and available evidence carry a strong implication that the in-flight structural failure was preceded by a loss of control with a consequential increase in speed to at least 260 knots. The most probable explanation for the loss of control is that the aircraft entered an area of unexpected turbulence of such severity as to deprive the pilots of full recovery.
The Inquiry gave a strong impetus for greater co-operation between the meteorological service and air traffic control; and for airline aircraft in Australia to be equipped with weather radar to give pilots of these aircraft the ability to avoid hazardous weather. All Australian airliners were required to be equipped with weather radar by 1 June 1963.
Aircraft
The aircraft was Vickers Viscount 720, serial number 46. It was registered VH-TVC and first flew on 17 November 1954. It was delivered to Trans Australia AirlinesTrans Australia Airlines
Trans Australia Airlines or TAA, was one of the two major Australian domestic airlines between its inception in 1946 and its sale to Qantas in May 1996. During that period TAA played a major part in the development of the Australian air transport industry...
on 8 December 1954 and named John Oxley
John Oxley
John Joseph William Molesworth Oxley was an explorer and surveyor of Australia in the early period of English colonisation.October 1802 he was engaged in coastal survey work including an expedition to Western Port in 1804-05...
in honour of an early Australian explorer and surveyor.
VH-TVC was leased to Ansett-ANA on 7 March 1960 and operated with the passenger cabin configured for 48 passengers.
The aircraft made 12,010 flights and flew for 16,946 hours.
See also
- Ansett-ANA Flight 149Ansett-ANA Flight 149On 22 September 1966 a Vickers Viscount aircraft departed from Mount Isa, Queensland, Australia for a 73 minute flight to Longreach. Forty-four minutes after takeoff a fire started in one of the engines. The crew were unable to extinguish the fire or feather the propeller so made an emergency...
– Vickers Viscount VH-RMI - MacRobertson Miller Airlines Flight 1750MacRobertson Miller Airlines Flight 1750On 31 December 1968 a Vickers Viscount aircraft departed from Perth, Western Australia for a flight of 724 nautical miles to Port Hedland. The aircraft crashed 28 nautical miles short of its destination with the loss of all twenty-six people on board...
- Vickers Viscount VH-RMQ - List of accidents and incidents involving the Vickers Viscount
- List of disasters in Australia by death toll
- List of accidents and incidents involving commercial aircraft
- List of accidents and incidents involving airliners by location