Was this a near miss?
June 10, 2006 4:42 PM   Subscribe

A plane I was on seemed to have a very close encounter with another plane. Is it possible to find reports of 'near miss' incidents online?

Yesterday I flew Vancouver - Ottawa, sitting in a window seat on the left of the plane. At one point, just as I happened to look out the window, a plane flew past us closer than I've ever seen another plane while flying.

My instinct tells me that it was less than a football field's length away, but given that my estimating skills may not be perfect, let's say it was 250' - 500' away. Exactly the same altitude as my plane - we went through it's vapour trail very soon (maybe 5 seconds) after passing it, with associated turbulence. On a clock face, if we were travelling 6 -> 12, it was travelling 2 -> 8. My plane did not take any noticeable evasive action. As I did not see the other plane's approach (only after it passed us) I don't know if it had to. My instinct also tells me that anybody looking out of the window on the other side of the plane might have had a few anxious moments.

What constitutes a near miss? How far apart should planes be when at the same altitude? Can I find out if this warranted any report by the pilot?
posted by valleys to Travel & Transportation (21 answers total) 1 user marked this as a favorite
NMACS database

See also here and here.

According to that NIMACS page, here's the definition of a near miss.

Gald you made it one piece.
posted by bim at 5:08 PM on June 10, 2006

As an aside - article in last weekend's Toronto Star about near miss collisions in Canadian skies.
posted by meerkatty at 5:16 PM on June 10, 2006

Depends on if the pilots reported it. (generally, they do...)

I used to work in a building next to an airport. We could see the runways from our office, and a couple of the guys kept air traffic control scanners so that they could listen to the tower. Still remember one time when we watched a military jet take off from the south runway under max power (against tower's orders) and turn out towards the river while a little Horizon Air prop job was taking off on the north runway... they came very close to one another, enough for the F-15's wash to affect the lift of the prop job. The tower said, "Horizon (Flight #), would you like to file a midair on that?" and the Horizon pilot answered in a shaky voice, "Horizon (Flight #), yeah, give us a few on that midair...", which my coworker said translated to, "Sure, after we clean out our shorts..."
posted by SpecialK at 5:20 PM on June 10, 2006

Plane to plane midair distances are exceptionally difficult to judge because of the lack of visual cues which we use when on the ground. A plane 1km away looks alarmingly large in the air.

If you were at cruising altitude, then assuming you were travelling at approx 500-600 km/h, in 5s you would have travelled about 700-800m, which is certainly within the 'near miss' category.
posted by unSane at 5:34 PM on June 10, 2006

wow, I was amazed to look at that NMAC site and see that 500 feet was regarded as the limit for near miss. My understanding was that anything less than 1km was cause for concern.
posted by unSane at 5:36 PM on June 10, 2006

In the United States I know that all aircraft are to be at least 2,000 feet away when in the air. It has substantially decreased over the years because of increased air traffic. Also, wake from other aircraft is the second highest cause of airplane crashes, FYI.

But Canada may be different. I don't know if that helps.
posted by thesiameseffect at 6:03 PM on June 10, 2006

My understanding was that anything less than 1km was cause for concern.

Maybe, but then they'd have to report more near misses.
posted by kirkaracha at 6:23 PM on June 10, 2006

thesiameseffect - got a citation for the "wake from other aircraft is the second highest cause of airplane crashes" comment? I find that exceedingly hard to believe. Pilot error, weather, and mechanical failure are a lot more likely to cause a crash than wake turbulence.

posted by autojack at 6:35 PM on June 10, 2006

Here's a good example of two planes that look really close but aren't.

posted by DieHipsterDie at 6:57 PM on June 10, 2006


So I may have been misinformed by almost every flight crew I have talked to, I do not know. Hell, I am always the first to say that I may be wrong. All I have to back myself up is the words of the many flight crew I have flown with. However, Pilot error (weather) may include airplane wake. Turbluence is caused by everything from weather to wake. It just may not be specific.

I apologize for the non-cited statistic. I'll definitely do my research next time.
posted by thesiameseffect at 7:01 PM on June 10, 2006

It appears that Canada has become tight lipped about its CADORS database claiming national security reasons as indicated in the notice.

Others seem to agree with this conclusion.

This newspaper report from last weekend seems to indicate that you aren't alone in a near miss in Canadian airspace.
posted by bim at 8:30 PM on June 10, 2006

The newspaper article above makes the important point:

"In congested skies, there's little room for error. For example, two commercial jets separated by four nautical miles and on a collision course would strike each other in less than 20 seconds."
posted by smackfu at 9:05 PM on June 10, 2006

That's not a near miss. It's a near hit! A collision is a near-miss. - George Carlin

Also, just to follow-up on this:
wake from other aircraft is the second highest cause of airplane crashes

Looking over AirDisaster's database, it appears that weather is the primary factor. Mid-air collisions are actually relatively rare.
posted by Civil_Disobedient at 5:30 AM on June 11, 2006

Heh - thanks for the correction C_D, that made me laugh.

Thanks for all the info. There are no matches for Friday in NMACS. Glad I saw those newspaper reports after the flight! Though I do have 4 more flights to look forward to this month... and given that I had a last-minute aborted landing a few months ago, I'd rather not have any more mid-air excitement.

My estimates were based on my gut feeling that the other plane looked about as big as it would if it were parked a couple of gates away at the airport - but of course it went through my field of view in a very short space of time. Even if it was more like 500m - 700m than 500', it was still too damn close for comfort.
posted by valleys at 7:32 AM on June 11, 2006

There are no matches for Friday in NMACS.

There are no matches for all of June. It looks like the latest record is from mid-May, so I'd say they have a 3-4 week lag to get entries in the system.
posted by smackfu at 8:27 AM on June 11, 2006

In the United States I know that all aircraft are to be at least 2,000 feet away when in the air...But Canada may be different.

The rules are international, and as follows for visual flight rules:

Vertical Separation:
below 29,000 feet: 1000 feet
above 29,000 ft: 2000 feet
(there's two more classifications higher than 45,000 ft for supersonic and military)

Horizontal Separation:
60 - 120 nautical miles or 10 - 30 minutes
(depending on route and aircraft type)

- from an FAA Air Traffic Control seminar handout
posted by Rash at 8:57 AM on June 11, 2006

And I agree with autojack about wake -- may have been true for a while, in the past, but that was long ago.

Incidentally, those of you into jargon might like to know that air traffic controllers (who mostly work in windowless buildings not necessarily anywhere near the airport, and definitely not in the tower) call an incident where two aircraft get too close a "deal."
posted by Rash at 9:01 AM on June 11, 2006

a 'deal' as in a hand of cards?
posted by mwhybark at 9:36 AM on June 11, 2006

This Ask the Pilot [salon.com] article about the 2002 mid-air crash in Europe gives a really detailed and easy read about near misses and collisions. I thought this was interesting:
Independent from the air-to-ground link with ATC, airliners today also carry onboard technology to protect them from collisions. Linked into the transponder systems, TCAS (traffic collision avoidance system, pronounced "tea-cass" in an almost folksy slang) gives pilots a graphic representation of nearby aircraft. TCAS will issue progressively ominous oral and visual commands (to climb or descend) once certain thresholds of distance and altitudes are crossed. If two aircraft are erroneously flying toward each other, their TCAS units work together, issuing "CLIMB!" instructions to one, and "DESCEND!" to the other.
posted by Staggering Jack at 9:48 AM on June 11, 2006

Valleys -- Have you considered contacting the airline, letting them know what you observed, and seeing what they say? Surely they would be interested to hear about this.
posted by jayder at 12:55 PM on June 11, 2006

I'm responding to this a little late - so who knows if you'll ever see it...

As an aviator and former air traffic controller, if both aircraft were under positive control by ATC (which they undoubtedly were), if the controller sees that the aircraft are going to be in any meaningful range of each other, the controller can call the aircraft out to each other as 'traffic' calls. (i.e."Traffic, two-oclock, 5 miles, southbound, 25,000 ft.)

If the pilots say they have a visual on each other, then separation minimums no longer apply. Although they'd be foolish to get TOO close to one another, if they have each other in sight and there's no resultant 'aluminum showers' then the sky's the limit! (so to speak).

I'm not sure on any airlines rules for minimums when it comes to VISUAL separations.
posted by matty at 6:55 PM on June 12, 2006

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