Father following a track log from a plane

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May 7th, 2018 at 8:13:20 PM permalink
Pacomartin
Member since: Oct 24, 2012
Threads: 1068
Posts: 12569
https://flightaware.com/live/flight/ACA307/history/20180506/2115Z/CYUL/CYVR/tracklog
Flight ✈ ACA307 ✈ 06-May-2018 ✈ CYUL - CYVR

A father was following this track log from a plane flying from Montreal to Vancouver. For twenty minutes he thinks his daughter is dying as altitudes are dropping and the lat and long are near Buffalo NY.

Takeoff 05:28:01 PM 45.5241 , -73.8964
11,700 05:28:25 PM 42.8667 , -78.7000
11,000 05:29:25 PM 42.9333 , -78.5833
10,500 05:30:24 PM 42.9333 , -78.4667
9,100 05:31:24 PM 42.9667 , -78.3500
7,500 05:32:25 PM 42.9833 , -78.2500
7,000 05:33:25 PM 43.0000 , -78.1500
7,000 05:34:25 PM 43.0333 , -78.0667
6,000 05:35:25 PM 43.0167 , -77.9667
4,600 05:36:24 PM 43.0000 , -77.8833
3,100 05:37:25 PM 42.9833 , -77.7833
2,400 05:38:25 PM 43.0167 , -77.7333
30,900 05:48:45 PM 45.9057 , -75.8430

What does it mean to have these kind of numbers in a flight log? They are not even physically possible.

May 7th, 2018 at 10:09:31 PM permalink
Fleastiff
Member since: Oct 27, 2012
Threads: 62
Posts: 7831
Telemetry problems?
Shift to different satellite?
Descent to pass under an area of controlled airspace and re-emerge into controlled airspace once a clearance is obtained?
Handshaking problem with a new gps satellite. An iridium sat phone once travelled 700 miles in thirty seconds in the middle of the Tasman Sea.
May 8th, 2018 at 12:08:21 AM permalink
Pacomartin
Member since: Oct 24, 2012
Threads: 1068
Posts: 12569
Quote: Fleastiff
Telemetry problems?
Shift to different satellite?
Descent to pass under an area of controlled airspace and re-emerge into controlled airspace once a clearance is obtained?
Handshaking problem with a new gps satellite. An iridium sat phone once travelled 700 miles in thirty seconds in the middle of the Tasman Sea.


Well I checked the same flight on three tracking problems, and they all show the same impossible flight pattern
https://flightaware.com/live/flight/ACA307/history/20180506/2115Z/CYUL/CYVR
https://www.flightstats.com/v2/flight-tracker/AC/307/2018/05/06/958226909
https://www.flightradar24.com/data/flights/ac307#1149c98a

AC 307 Air Canada YUL Montreal YVR Vancouver
Flight Departure Times 06-May-2018 Scheduled 17:15 EDT Actual 17:10 EDT
Flight Arrival Times 06-May-2018 Scheduled 19:40 PDT Actual 19:28 PDT
May 8th, 2018 at 10:05:43 PM permalink
beachbumbabs
Member since: Sep 3, 2013
Threads: 6
Posts: 1600
Paco,

I think it's a correlary to the garbage in, garbage out problem. ACA probably had either a malfunctioning altimeter and/or they set it wrong. Perhaps specifically when they climbed into the flight levels, they neglected to set/instrument failed to adjust to 29.92 crossing 18,000, which is the standard. The higher they climbed, the less accurate it would be, as fewer air molecules entered the pitot tube.

A more passive or understandable way this could happen is if the pitot tube de-ice malfunctioned and the opening narrowed causing erroneous readings. That would indicate progressively lower altitude even if the instruments were set correctly, as the tube became increasingly clogged with ice.

Could also.be a careless pre-flight walkaround ,when various instruments are checked for their caps being taken off. Ever seen all those little red.ribbons fluttering around a tied-down aircraft that say "remove before flight"? They protect those sensors.

So anyway, garbage sensor readings transmitted, and recorded on all those flight reporters, and read by you. If you look further in the record, I would guess the crew tried to correct the issue during climb out and finally succeeded.
Never doubt a small group of concerned citizens can change the world; it's the only thing ever has
May 9th, 2018 at 12:09:17 AM permalink
Pacomartin
Member since: Oct 24, 2012
Threads: 1068
Posts: 12569



Quote: beachbumbabs
Paco,
So anyway, garbage sensor readings transmitted, and recorded on all those flight reporters, and read by you. If you look further in the record, I would guess the crew tried to correct the issue during climb out and finally succeeded.


I wasn't sure if it was a problem on the plane or the ground. For ten minutes both the altitude and the position data is nonsense. Then there is no data for ten minutes, and once it resumes it makes sense, but the plane has flown 157 km.

But the bad data is still on the websites. The concerned father looking at those tracks and altitudes thought his daughter's plane is crashing. She called her from the plane and said one of the engines was out (which is ridiculous), but it her understanding of what they were telling her on the plane.
May 9th, 2018 at 5:13:46 AM permalink
beachbumbabs
Member since: Sep 3, 2013
Threads: 6
Posts: 1600
Quote: Pacomartin





I wasn't sure if it was a problem on the plane or the ground. For ten minutes both the altitude and the position data is nonsense. Then there is no data for ten minutes, and once it resumes it makes sense, but the plane has flown 157 km.

But the bad data is still on the websites. The concerned father looking at those tracks and altitudes thought his daughter's plane is crashing. She called her from the plane and said one of the engines was out (which is ridiculous), but it her understanding of what they were telling her on the plane.


Thanks for the plot. It almost HAS to have been the airplane instrumentation. The 10 min of no reports most likely means they turned the transponder off to reboot the system and problem-solve. ATC would have been.going nuts with that telemetry. They would have insisted the transponder be turned off rather than report erroneous data. Perhaps after the troubleshooting, they turned on a backup system.

If things got to where the crew said something to the pax, the crew may even have taken a turn or two in holding to figure out what was going on (10 min is a LONG time) before proceeding. But engine-out would have required a divert to nearest landing point, so seems very unlikely that daughter was accurate.
Never doubt a small group of concerned citizens can change the world; it's the only thing ever has
May 9th, 2018 at 6:40:54 AM permalink
Fleastiff
Member since: Oct 27, 2012
Threads: 62
Posts: 7831
Source of static air or a covered pitot tube would not only have given them erroneous altitude but also speed readings. They would have relied on a radio altimeter but if things were so unusual that they made a 'comforting' announcement they were probably engaging in some maneuvers they felt would throw off the ice or the offending sleeve.
May 9th, 2018 at 6:40:54 AM permalink
Fleastiff
Member since: Oct 27, 2012
Threads: 62
Posts: 7831
I wonder if ATC cares more about position or altitude reporting.
Would automatic alarms go off at ATC centers if the plane was reporting it was so low?
May 9th, 2018 at 8:03:38 AM permalink
Dalex64
Member since: Mar 8, 2014
Threads: 3
Posts: 3687
Quote: Fleastiff
I wonder if ATC cares more about position or altitude reporting.
Would automatic alarms go off at ATC centers if the plane was reporting it was so low?


The information on those websites is a copy of what ATC sees, acquired through various means, but not directly from the ATC control centers. What ATC sees is what is reported by the planes.

They care very much if the position, altitude, or speed information coming from the plane is wrong.
"Everyone is entitled to his own opinion, but not to his own facts." Daniel Patrick Moynihan
May 9th, 2018 at 8:04:49 AM permalink
beachbumbabs
Member since: Sep 3, 2013
Threads: 6
Posts: 1600
Quote: Fleastiff
I wonder if ATC cares more about position or altitude reporting.
Would automatic alarms go off at ATC centers if the plane was reporting it was so low?


There's terrain mapping on all radars. They program in minimum safe altitudes for terrain within an x-mile radius (depends on the radar and the type of airspace what the distance is) of the highest obstruction. An alarm goes off on a speaker if an aircraft goes below safe terrain (or their altitude readout indicates it erroneous or not) so everyone can hear it, not just the scope controller. It's a high priority to respond verbally to the alarm, which can't be suppressed or canceled.it's similar to the stall warning horn in the cockpit. It has to be resolved for the blare to stop.

Many, many saves involve timely intervention. Several huge ones involve pulling up that map and steering a trapped or in distress pilot around obstructions to survival.

That said, it's much easier to block a bunch of vertical airspace with a good location return than to guess where an aircraft really is with a false target indication.

When the FAA digitized primary returns (an asterix replacing a target smear), this is the biggest thing they lost. Very huge problem a small amount of the time. If the digital was erroneous, which happened often, you had the smear (external sensor confirmation of position) and could manually (easily) reposition the info tag onto the target as it moved. Also, based on pilot reports, update the tag to show altitude without Mode C sensor input.

When they digitized the centers, around 1998, they lost that confirmation info (in fact, the primary return was always the target actually separated, and the digital info tag overlaid was secondary ). It was a budget decision that was violently protested by the controllers. Ignored by Congress and HQ as not significant enough to justify the expense. Approach radars were next to be decommissioned. But then...

The 9/11 hijackers took advantage of this flaw and turned the transponders off as soon as they took over the airplanes. It was especially glaring for the American that hit the Pentagon: center lost them completely for hundreds of miles. They were seen (the primary) by Dulles Approach, no altitude info, just a smear going over 500 mph, no data tag. They tried to scramble an intercept on the target but were unable to catch it before it dived on the building.

One of the few "good" things to come out of 9/11 was that graphic and tragic demonstration of why we needed those systems that changed a lot of minds about primary systems. Not sure where things are now, though. Coming up on 10 years retired.
Never doubt a small group of concerned citizens can change the world; it's the only thing ever has
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