The last night I had an "interesting" experience with an aborted landing, which was a bit dramatic for my liking. Heavy fog and darkness didn't help either. Pilot told us that the reason for aborted landing is a problem with navigation instruments.

Today I checked the flightradar24 data, which I've attached for your pleasure, but it didn't ease my worries since according to site's data the first attempt missed the runway completely.

  1. How accurate are these flightradar's data?
  2. How common is for pilot to miss runway in heavy fog?
  3. Is there a reason to be worried while flying 50 feet above meadows in heavy fog? Possibly with malfunctioning navigation equipment?

flightradar24 data

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    $\begingroup$ Note that FR24 data is completely inaccurate, so the the two attempts not lining up do not reflect the actual landing attempts. $\endgroup$ – Sanchises Dec 15 '15 at 19:47
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    $\begingroup$ According to the map, the second (successful) attempt also missed the runway. Doesn’t that answer your question about accuracy? $\endgroup$ – chirlu Dec 15 '15 at 20:11
  • $\begingroup$ @chirlu Not really, it could be that Google Map is not aligned correctly $\endgroup$ – Mladen Janković Dec 15 '15 at 20:16
  • $\begingroup$ @MladenJanković, automotive navigation needs the map aligned accurately within couple of metres and since Google Map is good enough for that, it is aligned that accurately. $\endgroup$ – Jan Hudec Dec 15 '15 at 20:25
  • $\begingroup$ Aviation annals are full of the blood of unfortunates who's pilot ignored the go-around gremlin whispering in his ear. $\endgroup$ – radarbob Dec 15 '15 at 20:57

A go-around is nothing to be worried about as a passenger. What would be worrying is if the pilots elected not to go around when conditions warranted it.

The dark likely isn't an issue with this go around as approach lighting systems can become exceptionally bright when requested (to the point you'll need sunglasses to look at them if visibility is good). What was likely a factor was fog. Airplanes need a minimum amount of visibility to land and if conditions are marginal you won't really know until you fly the approach and either see the lights and land or do not see the lights and go around. For normal ILS approaches you would initiate this go around at 200 ft above the airport elevation. For very low visibility approaches this decision height may be 100 feet or less above the airport elevation.

The point at which you go around if you fail to see the runway environment is well defined and procedures ensure obstacle clearance so there is no danger as long as procedures are flown as published.

Another possibility for the go around could be the airplane in front of you failed to clear the runway speedily due to low visibility. If the preceding aircraft was still occupying the runway then your airplane would have to go around. There are a few other issues that could warrant missed approaches (e.g. windshear) but in all of these cases the go around is the safer option than proceeding with the landing.

Your pilots made the safe decision to go around and this is what you should take from the experience. There is zero reason to be worried.

To address your added specific questions:

  1. Flightradar24 flight track data is unreliable. It is neither true radar positioning or necessarily true GPS positioning. It is nice for zoomed out flight tracks but is not reliably suitable for the precision during landing/takeoff. Do not use it as a basis for worrying that your approach was not properly aligned.

  2. Extremely rarely if you mean not being aligned with the runway. Uncommon if you just mean not seeing the approach lights but otherwise on course to land. The navigation signals used in ILS approaches are broadcast down the runway centerline for the lateral guidance and from just next to the runway approximately 1000 feet past the beginning of the runway aimed 3 degrees up for the vertical guidance. These signals are only usable in a cone that radiated outward from the runway. Furthermore the navigation accuracy of the ILS receivers are regularly tested on the airplane. Combined with monitoring by air traffic controllers you will not end up on a parallel course that does not intersect the runway.

  3. The vertical data is also not reliable. Your airplane approached on the glideslope and if it made it down to 50 feet this would have been just over the very beginning of the runway. After initiating the go around it would climb (likely to between 2000 and 3000 feet) and attempt another ILS approach. At no time is the airplane lingering at 50 feet above the ground anywhere but over the runway for a very short period of time.

The video below is an example of a very low visibility approach and you can see an example of how low the airplane can get before visual contact is made with the approach lights and runway. At predetermined points based on the aircraft, airport and crew qualifications the airplane would initiate a go around if these things were not seen. For standard ILS approaches this would be when the airplane announces "200 feet". For category II ILS approaches, it would be at "100 feet". In the video below a category III approach is shown which has an even lower altitude to initiate a missed approach.

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    $\begingroup$ @MladenJanković I've added some points to my answer to address the stuff added to your question. $\endgroup$ – casey Dec 15 '15 at 20:03
  • $\begingroup$ Well, flightradar24 data is GPS if the aircraft has it. This one clearly didn't, though. $\endgroup$ – Jan Hudec Dec 15 '15 at 20:11
  1. How accurate are these flightradar's data?

Flightradar24 relies often on ADS-B transmissions from the aircraft. Depending on the aircraft the accuracy of the transmitted ADS-B position varies from very accurate to not accurate at all. This particular A319 belongs in the latter category; the source of the data was the Inertial Navigation System.

  1. How common is for pilot to miss runway in heavy fog?

Quite common. Depending on the aircraft, the flight crew and airport navigation facilities the aircraft can land in zero visibility. Nikola Tesla airport has Instrument Landing System (ILS) CAT IIIb on runway 12 (where you landed) which means that the navigation equipment can support autolanding. In this case the decision height can be at the runway, the minimum visibility at the runway is 50 meters. At the moment there is no Notice to Airmen (NOTAM) published regarding maintenance of the system so I assume it is operable.

I don't know whether this particular aircraft and its crew are approved for ILS CAT IIIb operations.

If either the airport, the aircraft or the flight crew cannot support autoland, then the runway has to be visible at a predefined height. If the runway is not in sight at this height the flight crew will follow the missed approach procedure.

  1. Is there a reason to be worried while flying 50 feet above meadows in heavy fog? Possibly with malfunctioning navigation equipment?

No there is no reason to worry. This is normal operation, it happens everyday somewhere in the world. The aircraft is guided by two independent guidance systems that cross check each other. If there is a discrepancy between the two, an alarm sounds and the approach is aborted.

The navigation system on the ground is carefully monitored, if anything malfunctions the system will raise an alarm. The area around the runway and especially around the antennae of the navigation system is kept clear of obstructions when the airport is under Low Visibility Procedures (LVP)


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