What qualifies as a near miss ?

[buckleydj]

Just wondering could any body clarify what type of incident qualifies as a near miss and what separation minimums are there for aircraft at cruise altitude.

Reason for this is my father was on an OS flight from PRN to VIE last week. From his window seat he saw an aircraft travelling at a perpendicular angle to his flight. He said the aircraft passed extremely closely to his. He is a seasoned passenger and would not be prone to story telling or nervous passenger syndrome. When he raised the incident with a member of the cabin crew he was told that it was nothing to worry about as there was a clear 150 meters of vertical separation. Is this sufficient.?? Would assume that TCAS would kick in if a collision was imminent but just checking.:confused: :confused:

[RadarContact]

Not sure how reliable the statement of the cabin crew member was, but standard vertical separation is 1000' or roughly 300m between two IFR flights. However, there might have been a VFR traffic (legally) flying 500' (150m) underneath, depending on altitude of the plane your father was flying in.

[Spitoon]

In the UK there is an AIRPROX (aircraft proximity) reporting system.

An AIRPROX is filed if, in the opinion of a pilot or a controller, the distance between two aircraft as well as their relative positions and speed have been such that the safety of the aircraft involved was or may have been compromised.

As you'll see there are no distances specified and the term 'near miss' has no official meaning in aviation circles. This means that an AIRPROX could be filed even if the normal separation that ATC provides exists. Conversely, aircraft can, in some situations such as that RadarContact describes, be much closer without causing a hazard or concern to the pilots.

Different countries apply the various classes of airspace differently and it is difficult to say whether anything was amiss without knowing exactly where this happened. In many classes of airspace a VFR fligh could, quite legitimately and quite safely, fly much closer than the 500ft vertical spacing that RadarContact mentions.

[buckleydj]

Thanks for the response guys. Obviously its not as simple as one might think depending on the circumstances as you say. Radarcontact - I think the FO had done his in flight announcement shortly before and said they were cruising at 32,000 feet when the paths crossed.

Given the sensitivity after the recent mid-air collision its no harm to know the facts before the great aviation rumour machine gets into gear. Thanks again:)

[Localiser Green]

This website has quite a good description of the various Airprox categories:

UK Airprox Board (http://www.ukab.org.uk)