Invicta International Airlines Flight 435

A Vickers Vanguard of Invicta International, similar to the crashed plane.

The Invicta International Airways Flight 435 was a charter flight en route from Bristol to Basel Mulhouse, which crashed in Hochwald (Canton Solothurn ) on 10 April 1973. It is so far the most serious accident in Switzerland and at the same time the most serious accident involving a Vickers Vanguard 952 In the crash 108 people were killed, 37 survived because they had been in the rear of the aircraft.

The plane, a four-engine propeller - engine with the aircraft registration G - AXOP, was there on behalf of a British charter airline and should fly in fog and blowing snow the airport Basel- Mulhouse. The pilots failed despite using the instrument landing system approach the runway, which is a random walk in the Basel region began. The machine crashed finally on a hillside near Hochwald.

History of the flight

The aircraft was en route from Luton to Basel. It was between landed in Bristol and raised there at 7:19 clock from GMT. After a flight time of ninety minutes, the co-pilot notified the control approach in Basel. The control tower confirmed the position and told the weather conditions on the ground. Thus, there was a wind speed of nine knots and at the bottom a sight of 700-1300 meters. The cloud base ceiling was located at an altitude of 120 m. There was snow and the air temperature was zero degrees. The air traffic controllers gave the pilot the statement initially to flight level 5000 feet and then drop to 4000 feet.

To 8:55:48 GMT clock announced the co-pilot that the aircraft is the outer marker - that was at the same time the beacon BN - have passed the instrument landing system. At this time, the air traffic controller issued the release for the descent to 2500 feet. Seventy seconds later the crew reported to have declined to 2500 feet. Another minute later she reported reaching the beacon MN and received clearance for the landing approach to runway 16 after a loop were the pilots to clock 9:00:13 permission to land.

The pilot - in -command reported at 9:05:12 clock that he would take off and make another landing attempt. The tower instructed the aircraft to, to an altitude of 2500 feet again the beacon BN to fly. Two minutes and 15 seconds later notified the flight crew, and claimed to have reached the beacon. The control tower then gave the instruction to control the beacon MN. In fact, the plane but was at this time southwest of the airport, about 15 km south of the beacon BN.

The tower reached at 9:08:10 clock the call of meteorologists at the weather station Binningen, about eight kilometers southeast of the airport. The meteorologist had the air traffic controller on a four-engine propeller plane towards which had flown only about 50 m above the ground on the weather station away and called for to inform the crew of the need for an immediate climb. Even during the phone call with the meteorologists reported flight crew of Flight 435 overflying the beacon MN, which is located some 18 km north of the airport. The approach control demanded that the flight crew to turn and driving on südsüdwestlichem course the beacon BN. Subsequent evaluation revealed that the pilots but not about six kilometers north of the airport, but the beacon immediately south of the runway lying BS overflown at this time the beacon BN.

To 9:11:10 clock asked at Tower Zurich, Basel whether an aircraft toward Hochwald watch as three to five nautical miles southwest of the Basel airport appears an unidentified echo on Zurich's radar screen. The air traffic controller in Basel said no at first, but then turned himself fixed an echo that moved in a southerly direction. Even during this call to Flight 435 reported and explained that they had reached the beacon BN. The control tower was thereupon release the landing.

The air traffic controller tried after the end of the call at 9:12:10 clock to ascertain whether the Vickers actually was located at the specified location, and to clock 9:12:33 confirmed the pilot, the machine befände on the glide slope. The air traffic controller asked to clock 9:13:03 Flight 435 from the current level. The request was answered by two pilots with 1400 foot. The note of air traffic controller that the machine has not been located south of the runway on the glide slope, but was not answered by the crew as the aircraft to clock 9:13:27 16 km south of the airport against a wooded hillside of the Swiss Jura bounced.

Weather conditions

During the landing approach, the aircraft was almost constantly in the clouds. There was a low point of view by blowing snow. This was caused by a cold air mass flow from the North Sea to the Mediterranean, which led to the upwelling of warmer air, and thus to formation of clouds and snowfall in the Rhine Valley. The flight weather was so unfavorable, as there was in the clouds danger of icing and turbulence, the strong north wind reached almost to the ground and visibility was poor.

The official weather records for Basel for 8:45 clock have easy quick drop off at 0 ° C and a ceiling cloud base of 120 m above ground as well as a runway visibility of 1300 m. At 9:15 clock, ie immediately after the crash, meteorologists recorded light snow at 0 ° C and a ceiling cloud base of 150 m and a runway visibility of 1700 m. The conditions at the alternate airports in Zurich and Geneva were sufficiently good relationship wide good conditions for a landing.

The visibility on the runway was measured at two points, at the decisive point in time of the accident - the range of vision wavered 500-550 m 9:03 to 9:09 clock.

At the crash site there was according to witnesses dense snowfall with a visibility of less than 50 m.

Aircraft

The Vickers Vanguard 952 was equipped with four Rolls Royce engines of the type 512 Tyne and four propellers De Havilland PD 223/466/3. The aircraft with the serial number 745 had at the time of the accident an age of ten years and eleven months. It made its first flight on May 1, 1962. The aircraft had completed 16,367 flight hours, the engines had 13262-14476 operating hours behind. The last Luftauglichkeitsprüfung came of May 1972 and the last maintenance was performed on March 24.

Crew

Both pilots had licenses, the pilot - in -command allowed them to fly as. Captain Anthony Dorman, a Canadian citizen, had in 1963 a flight training at the Canadian Air Force started, but this was abandoned for lack of talent. He had in 1966 a civilian ticket purchased, which he later expanded on commercial aircraft. 1969 was issued to him in Nigeria based on the Canadian pilot license and a supposedly successful completion of instrument flight check permission to perform commercial aircraft flying under instrument flight. In the later review, however, it turned out that in his flight log book, no such examination was recorded. Later he was in the UK instrument flight tests on aircraft of the types DC-3, DC -4 and Vickers Vanguard. In each case, he needed more than one attempt. The entire flight experience Dormans could not be determined because in the investigation of aircraft accident discrepancies in flight logbook Dormans came to light. For Invicta he flew 1088 hours on a Vickers Vanguard. In Basel, he was once landed 33, of which nine times with an instrument landing.

The co-pilot Ivory Terry was a British citizen. He began his flight training in October 1944 in the Royal Air Force and a flying experience of 9172 hours, including 1256 hours on the type of the crashed aircraft. He was previously landed 61 times in Basel, including 14 times with an instrument approach.

Both pilots had flown a total of 17 times together, including twice to Basel and had attended a service life of about four hours and 45 minutes on the unlucky day.

Investigation

The investigation of the accident flight was carried out by the Swiss Aircraft Accident Investigation Bureau (AAIB ). As with aircraft accidents usual with foreign aircraft, with the investigation of the Air Accidents Investigation Branch and the air safety authority in the home country of the crashed plane was involved. Since the Basel Mulhouse airport facilities for the instrument approach is including on French territory, the French authorities sent observers to the investigation.

The investigation revealed that on the one hand board radio and blind flying instrumentation not working flawless, on the other hand were training deficiencies in the pilot. Crash may have resulted the wrong reading the radio compass, the lack of synchronization with the second instrument and the disorientation of the pilots.

After the correct approach to the beacon the beacon BN BN was instead beacon MN, again approached. After a very sharp curve to the left U-turn should westward may lead to BN that the plane had already happened. Here the pilots exchanged their roles, with Terry as PiC. The destination point of the landing approach was too far south and too far west. The first error is detected, the second is not. After the go-around and flying the loop, the flight axis was shifted westward in a line with the runway, but almost to the distance BS -BN. Since his time in England no votes recorder was specified for this type of flight, no explanation is given for the last few seconds. The aircraft was in a climb. They did not keep at it and crashed.

It was the worst ever aviation accident in Switzerland and the worst accident disaster in the canton of Solothurn.

Source

• Official investigation report in a translation of the Air Accidents Investigation Branch (PDF, English, 4.41 MB) ( Archive) ( The original German text is not available online. ) Annexes to the report ( PDF, English, 3.89 MB) ( Archive )

47.4541805555567.6232Koordinaten: 47 ° 27 ' 15 " N, 7 ° 37' 24" E; CH1903: 613919/255949

• Aircraft Accident
• Aviation ( Switzerland )
• History (Canton Solothurn )
• Traffic accident in 1973
• Hochwald SO