Qatar Airways flight QTR901 registration A7-BEO departed Perth International Airport on runway 21 on 1st November 2022 at 15:06:50 UTC (23:06:50 AWST local time). There was good weather in the Perth area that evening with a high pressure zone and a surface pressure of 1023 hPa. There was a light north-westerly wind of 6 knots from 125°T.
The aircraft was picked up by ADS-B at 15:06:50 UTC showing a position of 31.9572°S 115.9600°E on a track of 195°T with a ground speed of 188 knots and an altitude of 50 feet just above the southern end of the runway 21. The aircraft continued to be tracked by ADS-B until 15:54:00 UTC, at which point the aircraft was out of range of any ADS-B receiver at a position of 29.2601°S 110.4681°E, which is 225 nmi west of Geraldton Airport, Australia out over the Indian Ocean. The aircraft was then on a track of 302°T with a ground speed of 466 knots at an altitude of 30,000 feet.
For 7 out of the next 10 hours the aircraft is out of range of any ADS-B receivers. After reaching Sri Lanka at 21:32 UTC the aircraft is back within range of ADS-B receivers for approximately 1.5 hours. Similarly when reaching the vicinity of the Arabian peninsular the aircraft’s position is again known from ADS-B data for a further 1.5 hours. This particular flight took a more northerly route due to the strong jet stream and flew over the Cocos Islands where it was also picked up by an ADS-B receiver for a short time around 18:36 UTC.
This case study examines the use of radio waves from the Weak Signal Propagation Reporter (WSPR) and the historic database called WSPRnet. WSPR data can be used as a multi-static passive radar system to detect and track aircraft.
We demonstrate that it is possible to detect and track a Boeing 777 across the Indian Ocean. Our methodology is applicable to the case of the missing aircraft MH370, which was a similar aircraft type namely a Boeing 777-200ER. Flight MH370 was diverted to the Indian Ocean, where it crashed after fuel exhaustion on 8th March 2014 at some point after the last satellite signal was received at 00:19:37 UTC. At the time of writing of this case study, MH370 still has not been found despite extensive surface and underwater searches.
The case study can be downloaded here (230 pages, 105 MB).