Beware the Essendon Ghost
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Beware the Essendon Ghost
Those of you who fly regularily into Melb. Any similar experiences?
A few days ago an RPT Turboprop aircraft with 33 POB was cleared to make a visual approach from "Sheed" (essentially over the threshold of RWY 26 Essendon) for a right base to RWY 34 at Tulla.
At about the same time the crew observed traffic on the TCAS 900' 1 o'clock high at approx 1-2 miles decending. Traffic became a (PT) and crew attempted to sight it without success.
With the traffic at 600' high and closing to within 1 mile, the TCAS generated a TA and the aurral warning "Traffic Traffic" was sounded. Still no sighting!
As the traffic closed to within 300' high and virtually no lateral seperation, three warnings were sounded in quick succession.
"MONITOR VERTICAL SPEED", then, "TCAS DESCENT", then "INCREASE VERTICAL SPEED".
At the onset of the first hard warning, the Captain who was the pilot flying, disconnected the autopilot and proceeded to fly in accordance with the R/A. The TCAS was commanding a rate of descent of no less than 2,500 FPM!
Prior to the activation of the TAWS, the R/A ceased and the Aurral advice, "CLEAR OF CONFLICT" sounded. Profile and flightpath were regained and the aircraft landed without further incident.
ATC Advised that there was no other observed radar traffic!?
The ATSB are investigating.
No fault could be found with the aircraft's systems.
A radio Tech has commented that a false scenerio could be generated by the unauthorised testing of a ground based TCAS unit. If the internal altimeter was raised in an active unit, in this case to approximately 3,400 feet with the mode C on, then disconnected and allowed to descend rapidly to sea level, any overflying aircraft's TCAS equipment would interpret that signal as a threat as the aircraft passed over it's position.
In this case, possibly a hangar at Essendon!
Imagine attempting the aforementioned manuever in a 200 tonne jet!
A few days ago an RPT Turboprop aircraft with 33 POB was cleared to make a visual approach from "Sheed" (essentially over the threshold of RWY 26 Essendon) for a right base to RWY 34 at Tulla.
At about the same time the crew observed traffic on the TCAS 900' 1 o'clock high at approx 1-2 miles decending. Traffic became a (PT) and crew attempted to sight it without success.
With the traffic at 600' high and closing to within 1 mile, the TCAS generated a TA and the aurral warning "Traffic Traffic" was sounded. Still no sighting!
As the traffic closed to within 300' high and virtually no lateral seperation, three warnings were sounded in quick succession.
"MONITOR VERTICAL SPEED", then, "TCAS DESCENT", then "INCREASE VERTICAL SPEED".
At the onset of the first hard warning, the Captain who was the pilot flying, disconnected the autopilot and proceeded to fly in accordance with the R/A. The TCAS was commanding a rate of descent of no less than 2,500 FPM!
Prior to the activation of the TAWS, the R/A ceased and the Aurral advice, "CLEAR OF CONFLICT" sounded. Profile and flightpath were regained and the aircraft landed without further incident.
ATC Advised that there was no other observed radar traffic!?
The ATSB are investigating.
No fault could be found with the aircraft's systems.
A radio Tech has commented that a false scenerio could be generated by the unauthorised testing of a ground based TCAS unit. If the internal altimeter was raised in an active unit, in this case to approximately 3,400 feet with the mode C on, then disconnected and allowed to descend rapidly to sea level, any overflying aircraft's TCAS equipment would interpret that signal as a threat as the aircraft passed over it's position.
In this case, possibly a hangar at Essendon!
Imagine attempting the aforementioned manuever in a 200 tonne jet!
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I believe that scenario has occurred in NZ in the last 18 months or so. I think it was raised in a presentation at the ANZASI conference last year. The false signal was coming from an aircraft undergoing maintenance at Aukland.
Nunc est bibendum
Speaking of TCAS 'ghosts', I've noticed that it's not unusual to get a traffic paint from warships of various nature. Often when flying into or out of Sydney I'll get a traffic paint of a ship either around Garden Island or off the coast. No altitude is ever recorded against it and it always disappears when within a couple of miles of it. Talking to some of the ex RAN crew that I've flown with, they've indicated that it could well be a HMAS squawking something.
Anyone else noticed this at all?
Anyone else noticed this at all?
This is what CASA have to say on the matter.
http://www.casa.gov.au/airworth/awb/34/009.pdf
There are cases where a full TCAS/Transponder functional check needs to be carried out (I've only ever done the full TCAS one on new installations) and antenna can't be blanked/disconnected - these are done inside a hangar with the doors closed.
http://www.casa.gov.au/airworth/awb/34/009.pdf
There are cases where a full TCAS/Transponder functional check needs to be carried out (I've only ever done the full TCAS one on new installations) and antenna can't be blanked/disconnected - these are done inside a hangar with the doors closed.
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I've noticed that it's not unusual to get a traffic paint from warships of various nature.
Bet you London to a brick that some clown has a transponder in a house/car with a variable altitude input-not difficult to do. The point on the ground will indicate the source. This would account for the fact that the ATC radar did not see it as it was below the "radar horizon".
Thread Starter
Keg,
Happens quite regularly.
There is a minesweeper base at Milsons point, and a transponder is usually always active there. No mode charlie, so the worst you will ever get is a T/A.
I've told ATC about it on numerous occasions but as there is no R/A they show little interest.
The warships in the harbour and off the coast quite often give the same result.
Next time you are on final for either 16L/R at Sydney, it will probably go P/T on your left as you cross the Parramatta river. The danger of that one is because it is so common, people may tend not to become alert when they pass over it and a T/A is generated.
The Melbourne incident is quite a different kettle of fish, and has serious safety issues for commercial aircraft. The knuckle dragger responsible should be hung up by the B@LLS!
Happens quite regularly.
There is a minesweeper base at Milsons point, and a transponder is usually always active there. No mode charlie, so the worst you will ever get is a T/A.
I've told ATC about it on numerous occasions but as there is no R/A they show little interest.
The warships in the harbour and off the coast quite often give the same result.
Next time you are on final for either 16L/R at Sydney, it will probably go P/T on your left as you cross the Parramatta river. The danger of that one is because it is so common, people may tend not to become alert when they pass over it and a T/A is generated.
The Melbourne incident is quite a different kettle of fish, and has serious safety issues for commercial aircraft. The knuckle dragger responsible should be hung up by the B@LLS!
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FWIW testing of the radars on the Perth class DDGs used to set off every car alarm in Potts Point and the 77 Sqn boys sometimes paint cars on the F3... apparently not hard to pick those with illicit radar detectors 
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