Mid-air Collisions
 

A comment elsewhere about the Pinner, or Northwood (depends which report you read) collision in 1948 between an RAF York and a SAS DC-6 led me to a search on Wikipedia, and I was astonished by the number of mid-airs between military aircraft, especially through to the 70s and 80s. Indeed the Northwood accident is claimed to be the last mid-air involving a civilian airliner in the UK. Anybody else looked at this aspect of aviation history. I found a long article about the Norhwood accident in a paper written for the local history society. I was surprised that I have no recollection of the accident itself, nor my parents discussing it, and we lived only about 4 or 5 miles from the crash site.

Collision over Copsewood (Northwood) 1948.
I flew with someone who remembered the location of the crash as a youngster in the 1950s. I then looked for it in the early 90s while walking the dog but was unable to find anything. I think I checked with the local history for information but no success. My family lived in Ickenham at the time of the accident but I never heard it discussed.
Mike

Mike - I will find the link and post it - map shows where the parts of the two aircraft fell


w

Flight article - https://www.flightglobal.com/pdfarch...0-%201020.html


Local History article - http://btckstorage.blob.core.windows...8%20Pg7-15.pdf


Seems in some places called the Northolt Disaster. Also seems there was a shortish thread on this topic in......2004!

Can't comment on civvie vs. Mil but mil on mil collisions sadly went with the territory and the time (Big air force compared with today, aircraft more basic, cold war tactics). Anyone who lived through that period will tell tales of the "F**** me that was close" moments or worse still tell tales of not realising you'd only just missed someone else until the debrief.

Why?

Firstly much more military aircraft around in the UK than there are now, all operating without any form of electronic collision avoidance. ( Look at the number of fast jet squadrons based in the UK now and compare with the number, say in 1980..)

Lots of formation flying ( not just the Reds, operationally as well, just about every sortie..shouldn't happen but there's always an increased risk of a clunk there)

Often as not operating (especially during training) in busy "open" airspace using "see and avoid" to hopefully prevent collision- e.g the airspace above Vale of York or Lincolnshire were general handling areas for several Basic Flying Training stations..on a clear day lots and lots and lots of Jet Provosts spinning/aerobating etc..

Down at low level almost everybody down at 250' agl, with high closing speeds, often with camouflaged aircraft, again only using Mk 1 eyeball for collision avoidance.

I can think of three alone in this respect.

2x Hunters at Valley.....sadly also killed holiday makers when the remains landed in the caravan park at the end of the runway. 1972 ( I think )

2x Buccs 15 Sqdn out of Karup....no casualties ( apart from some fish ) and a very enjoyable time in Denmark for me...fixing the one than landed safely and fishing ( quite literally, c/o a Grimsby based trawler) the remains of the other out of the sea. 1975

2x Jags 17 Sqdn 1980....sadly one fatality

There have also been a number of well-known military vs GA midairs over the UK in recent decades.

The Northwood mid-air collision was that which cost Douglas Pobjoy his life.

FV - as in the Pobjoy engine?

That's yer man!

Northwood collision insurance settlement
 

The late Charles Hughesdon had made a coup by getting ABA Sweden's insurance business before and during the war and secured the business of the new SAS conglomerate. His account of the insurance settlement of the collision between the SAS DC-6 and RAF York is related in pp151-155 of his autobiography 'Flying made it happen' (2003) in this scan embed (abridged slightly). (Hughesdon (d.2014 aged 104) is a little inaccurate on the destination airport and pax numbers)

My question is: 'Is the stack separation( raised to 1000ft in 1948) still sufficient for airliners up to 8x the weight, 2x the linear size and with a stacking speed maybe 50% higher?

http://i809.photobucket.com/albums/z...psofql3gpf.jpg

http://i809.photobucket.com/albums/z...psendnengr.jpg

I wonder if Mr Patterson told his partners what he was requiring from the underwriters? It does rather fly in the face of the concept of partnership and, if witheld from them, that of uberrima fides!

In keeping with the rest of your post, if you want to know how risky someting is, ask an insurance underwriter. :O

AFAIK there is no record of the insurance industry having declined to cover airlines who use the standard 1000' hold separation, so I think it's reasonable to conclude that it's not considered to be particularly risky.

And in the UK at least, aircraft in the hold don't use local pressure settings (QFE/QNH) so the issue of incorrect altimeter settings doesn't arise.

Tell me about it...

I'm just making the point that it was considered wise in 1948 to double the stack separation to 1000ft and now aircraft are up to 8x heavier (with stronger wakes), up to 2x larger (linear) and faster in the stack so is the separation still proportionate? Has it been reviewed in the light of airmiss statistics?

Airmisses involving aircraft in the hold are extremely rare.

ATC can monitor aircraft altitudes much more closely than they could in 1948.

I did my ATCO Cadet PPL Course at Cambridge on 1971. My first solo was in C150 G-ATKF which had been involved in a mid air collision with a Varsity out of Oakington a short while before. The instructor who sent me solo told me about the mid air; he had intimate knowledge as he had been the instructor at the time!!

Chev - happened in 65/66 time too, with a load of baby navs in the Varsity that time, some destined for Basssingbourn. As a result of the accident they were delayed a course or two so I ended up sans nav, and ended up going to 360 as first "first tourist" in Signals Command since I think the War

Chev,

I don't recall a Varsity v Cessna incident. Varsity v Sea Prince I knew about, but not the one you refer to. Could you provide details?

YS

Secret profit - sounds close to professional misconduct, but then regulation was much less stringent than now