Flight Aware Odd Data

AdamZ

AdamZ

Touchdown! Greaser!
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Feb 24, 2005
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Montgomery County PA
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Display name:
Adam Zucker
I am confused about a flight aware track from a flight I took yesterday. I flew to a NE Bonanza Group get together and took along Gary Shelby from POA and my CFII who is based at a field about 15nm away. The night before I filed an IFR flight plan from KPTW to KGED.

I Plug in D-> KPTW in the new IFD 540 (I have full ADS B In and Out) departed from my homefield with Gary and climbed to perhaps 2000' fly the 14-15 nm land at KPTW whose elevation is about 308' taxi off to an area that is about 30' lower than the runway, Shut down, pick up my CFII. Gary gets out and gets in back. We start back up and then Program in the flight plan into the IFD 540. We had some trouble but finally got the flight plan plugged in airborne. After picking up our clearance we were on our way.

I went to check my flight aware track today and The first thing that suck out was that my track for the 15nm leg from KLOM to KPTW appeared on the map even though that was not part of the flight plan nor was I on flight following.

The second oddity was that my reported altitudes were off by 100' to 300'.
I the altitude show at KPTW was 900' but the airport is 308' and I was below that when taxiing. Also the flight to KGED was at 4000' I had the altitude pegged on the altimeter and yet it showed me at 200' to sometimes 300' lower. I'd think if the encoder or something were off and I was 2-300' lower ATC would have said something. I know my CFII would have been all over me.

So is there something with ADS-B where Flight Aware will track a flight that is not on an instrument flight plan or Flight Following and is there some reason FA would show me that far off altitude?

Here is the FA link http://flightaware.com/live/flight/N519PH
 
Were you spot on on the altimeter setting? That can make a difference...
 
I haven't seen FlightAware track me unless I've been on FF or IFR. The 'kota has been ADS-B out for over a year now.

I've noticed the same thing on altitude since FlightAware has started using ADS-B data. That info can't be corrected for altimiter setting.

edit: I just looked at my flight to Gastons and when FlightAware was reading center data I was shown as on altitude and when they were using ADS-B data I was shown as off altitude by a couple hundred feet (typically).
 
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Kelvin said:
Were you spot on on the altimeter setting? That can make a difference...
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Kelvin, I really thought I was. If I was 2-300 feet off I'd think that even if I appeared to be at altitude in the plane ATC would have asked me about the deviation.
 
AdamZ said:
Kelvin, I really thought I was. If I was 2-300 feet off I'd think that even if I appeared to be at altitude in the plane ATC would have asked me about the deviation.
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Most likely you were Adam, the times I have been 'off' on FA were flights that the baro changed and I didn't keep up with it...but them only 60-100'. It is a possibility but you are right about ATC asking about it...
 
Van Johnston said:
FA is now supplementing the FAA ATC data with realtime ADS-B data received from private feeders.

http://flightaware.com/adsb/
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And it's buggy as HELL. I've seen a very large number of unphysical tracks. Just last week, a buddy's 737 trip teleported from overflying San Jose to taking off at Denver and lost 30,000 feet as it switched from Oakland Center to ADSB. Obviously, the ADSB service had the wrong flight.
 
FlightAware said my recent flight in a C172 crossed the Atlantic and landed in Africa!

(Track was normal but for some reason there was one last data point in Africa that caused the site to draw my green line as crossing the Atlantic)
 
If you think your onboard equipment (altimeter & encoder) might be at fault, take your plane to the avionics shop. But as long as you feel that the flight went well and ATC did not question you about your altitude, why worry about what flight aware shows? Just do not forget to consider that your encoder is always reporting at 29.92 and not what you set in the kollsman. Plus GPS altitude can vary from altimeter altitude as well and GPS is what ADS-B uses. I see no cause for concern unless ATC is screaming at you or your altimeter shows to be significantly off at field elevation.
 
If you have consistent altitude errors in the FlightAware data I concur that you should check your transponder's alt reporting function. Easiest thing to do is ask ATC to tell you what they see on their screen and cross-check that against your altimeter. If it's off then one of the two needs some TLC.

Had this happen once and indeed the Mode C altimeter needed some adjustment.

Remember FlightAware gets its alt data from your transponder, not the altimeter in the panel, and on many transponders you can't see what altitude it's sending out (some do show pressure alt on the screen).

One Q... what is FlightAware citing as the data source for the questionable data? ADS-B or Radar data (e.g. it will list the name of a TRACON / Approach or Center).
 
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SkyDog58 said:
Plus GPS altitude can vary from altimeter altitude as well and GPS is what ADS-B uses.
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ADS-B reports pressure altitude along with geometric altitude...
 
MAKG1 said:
And it's buggy as HELL. I've seen a very large number of unphysical tracks. Just last week, a buddy's 737 trip teleported from overflying San Jose to taking off at Denver and lost 30,000 feet as it switched from Oakland Center to ADSB. Obviously, the ADSB service had the wrong flight.
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You know I think that might be it. I went back and Looked and everything was reported by FA's ADS-B owned sites. The perplexing thing is how it picked up my VFR repositioning flight.
 
AdamZ said:
You know I think that might be it. I went back and Looked and everything was reported by FA's ADS-B owned sites. The perplexing thing is how it picked up my VFR repositioning flight.
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Just a guess but maybe having an IFR plan in the system may have triggered FA to "listen" for ADS-B data. Easy enough to test next time anyone (IFR rated) goes flying.

Looking at my Gastons flight, data started before I got my clearance. Data did stop as soon as I canceled my clearance west of Gastons.
 
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I've seen all sorts of oddities on flightaware. IMO, it's something that should be considered for entertainment use only, I wouldn't take any data on it very seriously.
 
I like giving it to friends/family when I'm flying to meet them so they can see my progress and estimated arrival time. Although I do always point out that the data can be iffy and if the data drops out don't worry.
 
cowman said:
I've seen all sorts of oddities on flightaware. IMO, it's something that should be considered for entertainment use only, I wouldn't take any data on it very seriously.
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100% agree. Not sure why a pilot would be worried about or all that interested in how their flight displayed on it.
 
cowman said:
I've seen all sorts of oddities on flightaware. IMO, it's something that should be considered for entertainment use only, I wouldn't take any data on it very seriously.
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Yep. I've seen flightaware showing my airplane doing some really weird things.

I don't even bother to look at it anymore... If I want to see my flight track I just record the flight with my Stratus. Much more accurate.
 
FlightAware anomalies are common. Just wait until you have a "Result Unknown?" and your wife starts calling/texting to make sure you didn't crash.

My guess is that the timing for the KLOM to KPTW leg was such that it included it on your other leg (being ADS-B equipped). Don't worry about the altitudes and speeds being off, they will be. Sometimes you'll see a spike where altitudes/speeds will jump low/high by a ton and then jump right back.

Interestingly, Adam, the pics on FlightAware of your plane were posted at KIPT by a guy I knew there. :)
 
I have my plane "monitored" by FA. Any call to ATC that gets you in the system produces a track and I get notified by email and text. Odd thing that happened to me was that track for a particular flight started in the middle of LI sound and ended in the middle of the forest several miles shy of the destination airport.... when I canceled flight following.
 
Not uncommon to see spurious data on Flight Aware. 900' may have been where they lost your radar track so that was the final altitude. I made the mistake once of telling my mom to watch Flight Aware so she would know when I was getting in. They dropped my track halfway and my mom thought I crashed. Luckily she called the airport FBO I used there and they inquired with ATC who told them I was with Indianapolis Center about an hour out.
 
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Ted DuPuis said:
FlightAware anomalies are common. Just wait until you have a "Result Unknown?" and your wife starts calling/texting to make sure you didn't crash.
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One time Flightradar24 just showed a flight of mine ending 10 miles short of the airport with a "?" at the end of the radar track. Yeah, that freaked a few people out.
 
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