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-   -   F-111E crash, 68-0018, Perthshire, January 1972 (https://www.pprune.org/aviation-history-nostalgia/605789-f-111e-crash-68-0018-perthshire-january-1972-a.html)

MJSC 23rd Feb 2018 16:54

F-111E crash, 68-0018, Perthshire, January 1972
 
Hello all,

This accident occurred close to where I live. Whilst idly browsing the web I only discovered this incident today. I run and cycle past the area for decades now and thus I am familiar with the landscape in the immediate area.

The F111-E struck a hillside in the Sidlaw Hills south of Coupar Angus 18 th January 1972

I have discovered useful links to the incident at the Aviation Safety Network and the raf upper heyford link is very useful as it shows 10 or so well composed pictures of the locus

Years ago, going back to the 1980-90's the area in which the incident occurred would host all sorts of low flying aircraft... hardly any now.

I appreciate the incident was more than 40 years ago so memories will be hard to come by. I am interested though in further information and eye witness reports on the crash and recovery.

I hold no expertise in this area and would like to view some opinions on points of interest to me, such as -

I understand the aircraft was en route to RAF Leuchars as opposed to the F-111's home airfield... why would an F-111 be heading to an RAF base I think hosting Phantoms/Lightnings ? To refuel ? A break for the crew ?

The pics show the aircraft heavily damaged but largely intact - I might have thought the aircraft would have broken into many pieces - what can be taken from this fact ?

I thought this type of aircraft had TFR - was TFR turned off or non-operational ? Or is that a simplistic assumption ?

Seeing the area now it is hard to square that such a violent event actually happened but that is life for you.

Many thanks for reading and your response

jimjim1 23rd Feb 2018 21:03

F-111E tail numbers

Says:-


Crashed and destroyed 18 January 1972 in Scotland (Ben Marselis) RAF Leuchars (Doc Servo). Killed were LT COL Floyd B. Sweet and LT COL Kenneth T. Blank (Doc Servo).
55th TFS, 20th TFW, tail code "JS".

A member of the board of investigation states that weather was not a factor, and that eyewitnesses saw the aircraft from over a mile away. He says the accident occurred because the crew failed to extend the wings forward to the landing configuration following a high altitude navigation mission. The wings were at the 35 degree sweep when the aircraft entered the GCA pattern and when the base leg to final turn was initiated, the aircraft stalled and was too low to the ground to permit recovery. It was determined that the aircraft's stall speed in that configuration was approximately 235 knots. (WK)

Crashed whilst on a routine ground controlled approach to RAF Leuchars, crashed approximately 975 ft on a snow covered 1,050 ft high mountain in the Hallyburton forrest area, near Burrelton, Perthshire, Scotland. approximately 3 1/2 miles south of Coupar Angus, 15 miles north west of Leuchars. Ordanance Survey map "Blairgowrie" sheet 49. one inch to a mile, m722 series edition 1-gsgs, map reference 345233, in the Sidlaw Hill's (map now not produced). (Richard J. Elliott)
The site is asking for pictures of this aircraft.

GLIDER 90 23rd Feb 2018 21:30

F-111E Crash, Perthshire, January 1972.
 
Maybe they were on route to RAFLeuchars to do a PAR or ILS before departing back to RAF Upper Heyford.

Regards

Glider 90

DaveReidUK 23rd Feb 2018 23:06

1 Attachment(s)

Originally Posted by jimjim1 (Post 10063051)
The site is asking for pictures of this aircraft.

Several photos of the crash site on the net.

galaxy flyer 23rd Feb 2018 23:49

Probably an instrument training sortie; perhaps weather-cancelled range mission; perhaps “burning flying time” because Wing was behind the time line. TFR wasn’t used as an IMC approach device.

GF

Chewbydoo 16th Mar 2018 15:57

I remember this event very clearly and have been in touch with relatives of Col Sweet through a posting on Pprune a number of years ago. The accident report from memory concluded that the wings had not extended fully and the aircraft stalled. The site was cleaned up very quickly. The map references given were correct at the time but the coordinates have changed with updated OS Maps. The site is to the right of the hill going up Tullybaccart from Coupar Angus to Birkhill.

MJSC 16th Mar 2018 17:22

Hello and thanks for all the responses to date, very informative.

I obtained a newspaper report of the crash from ' The Courier and Advertiser ' from the archives of DC Thomson which makes for interesting reading but for whatever reason I cannot upload either as PDF or jpeg...

I can fwd as to those who might be interested.

Thanks.

SMK111 5th Sep 2018 21:48

I would very much appreciate you sending me the Courier article. I was ay UPH a few years after the accident and would like to read your details.

[email protected] Many thanks.

sedburgh 6th Sep 2018 14:56


Originally Posted by Chewbydoo (Post 10085976)
The map references given were correct at the time but the coordinates have changed with updated OS Maps. The site is to the right of the hill going up Tullybaccart from Coupar Angus to Birkhill.

I think that the grid reference given is written backwards, NO 233345 (instead of 345233) is more plausible.

SMK111 6th Sep 2018 20:57

Interestingly - I have discovered that both pilots were highly decorated VN vets. It is difficult to understand how such an accident could happen w/o an aircraft malfunction. The squadron bar at the 77 TFS UPH was named after the pilot - Ltc Floyd Sweet - the bar name was Sweet Floyd's.

megan 7th Sep 2018 02:39


I have discovered that both pilots were highly decorated VN vets. It is difficult to understand how such an accident could happen w/o an aircraft malfunction
It matters little how much experience a person has, being human all of us are capable of have a very, very bad day. LT COL Floyd B. Sweet was undergoing transition training and LT COL Kenneth T. Blank was his Flight Instructor. The accident was not unlike forgetting to put the gear down, except how many aircraft have wing sweep, so no experience or ingrained habit/muscle memory there to rely on.

https://aviation-safety.net/wikibase/wiki.php?id=152852

Blank had flown his 100th mission over North Vietnam with the 34 TFS in December 1966. By the time of his last F-105 flight in June 1967, he had accumulated 672 hours in the aircraft.

http://34tfsthuds.us/resources/Pictu..._Kenneth_T.pdf

What was LT COL. Sweet's Vietnam experience, could not find anything.

washoutt 7th Sep 2018 08:55

Does a swing-wing not have a level 1 warning if gear down selection with swing swept back, ref if speed below a margin above stall speed in swept position or below critical height above terrain? Even when designed to mil spec?

SMK111 7th Sep 2018 15:26

I get that anyone can have a bad day - and certainly from personal esperiemce - flying in a snow storm requires increased concentration. The news report states that witnesses heard the engines accelerating meaning the crew knew they were in trouble - but it may have been too late. And true both came up in fixed wing aircraft. So sweeping the wings forward is new.

I wish we had access to the official accident report - that would shed some light on this unfortunate accident. LTC Sweet left a wife and 2 young girls behind.

Steve.

megan 8th Sep 2018 02:30

Wing sweep is linked to the flaps (flap handle is locked in the UP position if sweep is more than 26.5°), no interlock with the gear. Manual says stall can occur with no warning (buffet). Pre, during and post stall can be deceptively smooth and comfortable. The timing of recovery control application is critical. A momentary delay may mean complete loss of control and possibly loss of the aircraft. Stall avoidance is of particular importance, since the chances of recovery from a fully developed out of control condition are not good due to large altitude losses. Aircraft drag may exceed total thrust available. Is this what may have been their undoing?

T.O. 1F-111F-1 Flight manual USAF Series F-111F

washoutt 8th Sep 2018 09:00

Thanks for the info, Megan. An alltogether different design philosophy from civil aircraft. I wonder how Boeing went about this in the '70's when designing their SST.

SMK111 11th Sep 2018 16:42


Originally Posted by washoutt (Post 10244084)
Thanks for the info, Megan. An alltogether different design philosophy from civil aircraft. I wonder how Boeing went about this in the '70's when designing their SST.

Megan - yes if the wings are not moved forward and proper air speed is not maintained a stall or a descent will occur. The news article states there was a low cloud deck and some snow. If the crew was conducting low level TFR in the Highland Restricted Area (HRA) as I had done - it would be a very quick transition to a traffic pattern at Leuchars. The HRA was directly to the NW and exits near Leuchars. In TFR flying wings were typically set at 54 degrees. I could imagine the crew was scrambling to transition to a slower speed radar traffic pattern (changing frequencies - talking to the controller - changing transponder code - getting the radar approach book open - ect) doing it in bad weather only makes it more difficult.

SMK111 26th Sep 2018 21:47

I am doing a five part story on this accident - part 1 is now posted on Facebook - 77th tactical fighter squadron. Let me know what you think.

ChristySweet 1st Apr 2019 09:14

It was a training mission- I have no idea why they were on approach to that base- unless they were training on approaches using the GTR - which was still in a testing phase, actually. Sweet was behind in check hours and should not have been in that aircraft- which he, incidentally- was cussing over and calling a piece of crap the evening before at dinner. I am his younger daughter. We got a lot of contradictory info, including weather was a factor- then it wasn't. I'd like to find a good attorney to take on a lawsuit against USAF and Lockheed- which bought out Gen Dynamics. Some Australian AF mechanics have given me info on the wing sweep actuators being prone to freezing up after high altitude runs- that had to be fixed.
Once upon a time a lawyer for Lockheed made an unfortunate statement "It's cheaper to pay off the families than fix the planes.."
I'd like to make him eat those words


Originally Posted by MJSC (Post 10062774)
Hello all,

This accident occurred close to where I live. Whilst idly browsing the web I only discovered this incident today. I run and cycle past the area for decades now and thus I am familiar with the landscape in the immediate area.

The F111-E struck a hillside in the Sidlaw Hills south of Coupar Angus 18 th January 1972

I have discovered useful links to the incident at the Aviation Safety Network and the raf upper heyford link is very useful as it shows 10 or so well composed pictures of the locus

Years ago, going back to the 1980-90's the area in which the incident occurred would host all sorts of low flying aircraft... hardly any now.

I appreciate the incident was more than 40 years ago so memories will be hard to come by. I am interested though in further information and eye witness reports on the crash and recovery.

I hold no expertise in this area and would like to view some opinions on points of interest to me, such as -

I understand the aircraft was en route to RAF Leuchars as opposed to the F-111's home airfield... why would an F-111 be heading to an RAF base I think hosting Phantoms/Lightnings ? To refuel ? A break for the crew ?

The pics show the aircraft heavily damaged but largely intact - I might have thought the aircraft would have broken into many pieces - what can be taken from this fact ?

I thought this type of aircraft had TFR - was TFR turned off or non-operational ? Or is that a simplistic assumption ?

Seeing the area now it is hard to square that such a violent event actually happened but that is life for you.

Many thanks for reading and your response



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