Mosquito LR412

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Mosquito LR412, propeller hub.

Grid reference SH 85660 21485

On 9th February 1944 Mosquito LR412 – a photo reconnaissance aircraft – crashed on the mountain of Aran Fawddwy in Snowdonia, Wales.

Both crewmen, pilot Flying Officer Marek Ostaja-Slonski (PAF) and navigator Flight Lieutenant Paul Riches DFC (RAF) were killed in the crash. They had been on a cross country exercise coupled with the testing of newly fitted flaps.

The cause of the crash remains unknown. It was five days after the crash before a hill farmer spotted and reported the missing aircraft.

The crewmen were buried together at Chessington in Surrey. Flt Lt Riches was from Epsom in Surrey but F/O Ostaja-Slonski was of the Polish Air Force. It would appear his burial alongside his navigator was a touching gesture by the family of Flt Lt Riches.

The two airmen, side by side in their Mosquito and buried together too.
Photo from this site;

A photo of this very Mosquito; LR412 of 540 Squadron.

mosquito LR412
Photo from History of War;

One of the Rolls Royce Merlin engines of LR412 forms an unofficial memorial to the crewmen. Embedded in concrete it is sited at the entrance to Esgair-Gawr Farm. Llanwrog Mountain Rescue Service brought the bodies of the two airman off the hills and along this road in the early hours of February 15th 1944.

UPDATE 05 June 2024

Howard Kirby (see comments further below) visited the crash site last month with the sole purpose of finding the prop in the lead photo which others had been unable to locate. He has very kindly provided the grid reference for the prop and for another debris pool and also these photos.

Howard writes, “There is also another pile of wreckage next to a big boulder further down the bank from your coordinates too which is also slightly hidden from the main path which follows the fenceline (probably a good thing) as it is in a small gully.”

Prop SH 85638 21568
Pile by boulder SH 85556 21441

These seven photos © Howard Kirby and used with permission








12 comments on “Mosquito LR412
  1. Kingsdude/Dave says:

    Great photo Ian and great background info as ever – keep up the good work

  2. Mike_Infocus says:

    Last week I met the farmer who helped bring the engine down from the hillside 20 or so years ago,his wife remembers the crash.
    Snowdonia national park authority wanted to clear the area of "scrap" but the local people got together, rescued the engine and persuaded the authority to mount it as a war memorial.It was subsequently consecrated.
    The other engine survived in far better condition and is in the care of another local farmer who has retained it as a reminder of those who gave their lives for us.
    He told me that not long ago he met the pilot,now quite an old man, from the lead aircraft who was miles away when he noticed that LR412 had disappeared,he had come to pay his respects to a fallen colleague.
    I found it all very touching.

  3. Ian D B says:

    Thanks Mike, very interesting additional notes. They can be moving places. My mate always feels that way about sites where the prop remains, they are poignant reminders.

  4. cgullz says:

    the composition here is striking, the wee red poppy ever so poignant [i’m also listening to Dvorak Cello Concerto which probably further heightens the emotions here]. great lay of the land shot, the grass just through the snow shows the passage of time which is further reflected in the wear to the prop hub. i always thought if i was ‘back then’ i’d try for photo recon, risky as it was: not really the fighting sort, but recon – well it’s like research on wings innit?
    that animated clip was brilliant!

  5. Glenn Riches says:

    It is with great thanks for the pictures and write up, as they helped our family locate the memorial and crash site. In memory of our great-uncle, Paul Riches

  6. Howard says:

    Hi Ian,
    I have a photo of the propeller from my walk in 2011 but when I walked up Aran in 2018 I couldn’t find it. I thought maybe I was mistaken so walked the area again last week ( March 2024 ) and literally zig zagged the crash site, found all the other piles of remains but again no prop so I was quite disappointed. It saddens me that someone would take this, most walkers are respectful people. I’m wondering if someone went up there on purpose to pick it. How on earth would anyone carry it all the way down to the car park, its not something you can fit in a rucksack!
    Next time I walk up there, I’ll have another proper search but its not something that can be missed easily so I am not expecting anything.

    • Ian D B says:

      Hi Howard,

      Yes it is disappointing if the prop has been removed from Aran Fawddwy. It’ll probably be in someone’s garden now as a unique feature or something. God knows why they do it.

      I was contacted a couple of years ago by the author of this piece in Trail magazine (to read the article, you may have to provide an email address and a password but nothing more). She ended up using my old photo above for the article being unable to find the propeller herself.

      It’s possible the coordinates were recorded incorrectly but I don’t think so. It is also possible that whomever decided to steal it was unable to get it off the mountainside and dumped it on the way back to the van? It could be anywhere.

      Do let me know if you find it – a photo and confirmed grid reference would be appreciated.

      Best wishes,


      • Howard Kirby says:

        Hi Ian.
        Thanks for the reply. The coordinates are indeed correct for the main piles of wreckage but I read on another blog that the prop was further up the bank a bit from the main pile, so there is a small glimmer of hope. I read the article in Trail mag after my recent visit which seemed to confirm my disappointment at the time.
        Hopefully we are both wrong and I will of course report back after my next visit. I will try and get up there on a nice quiet week day sometime over the next few months.

  7. A fascinating account; I’ve taken the liberty of copying the salient details, fully credited, to create a Pseudo Report A for the official records of the RAF Llandwrog MRT and passed a copy onto the AirWorld Museum at what is now Caernarvon Airport.
    If you come across any more crash sites where the RAF Mountain Rescue Service were involved please do let me know at

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