Quiz: what happened to this YaK?

Thanks for the reply!

I had confused MPD with “maintenance planning document” with “mandatory permit directive” 😮 Thanks for the link anyway, the yakuk people have been wonderful posting all that information.

For the owner of the machine above – if there is no specific inspection specified a boroscope (internal visual) or an ultrasonic might be the go. The ultrasonic would first measure the thickness of the tank wall then look for discrepancies in that thickness (ie corrosion). Just a suggestion as I was wondering what I would do in the same situation.

Cheers!

Hamtech

The MPD’s for Yak aircraft are listed here http://www.yakuk.com/mpd.htm

The only one not listed is the 1998-017 R3 MPD regarding
airframe life limitations and overhaul life, this is probably
because the work needed to be carried out has not been
agreed with the CAA yet.

Hello all,

Thank-you for the post, I have added these images to my collection. I’m currently compiling details regarding the maintenance and certification of Russian aircraft in western countries.

May I ask is the British CAA preparing a generic MPD for the Yak-52? The last couple of posts suggested this.

Thanks in advance for any replies.

– Hamtech.

The CAA are to issue yet another MPD regarding the air bottles, requiring they are checked with an internal inspection and hydrostatic test.

What with the airframe MPD (still not resolved) the CAA are giving us Yak 52 flyers are hard time at the moment.

Still a great plane to fly, and as Yakrider says, lots of character. I love it more than the missus, at least thats what she says!

I think x-raying the bottles would be the answer rather than a pressure test if corrosion is suspected. As for the Yak itself I have worked on Yak 50/52/55 and they are far superior to some of the Western machines that are around. The best ones seem to be the earlier production machines.

Oil does drain down into the bottom cylinders. That’s why we run the engines up before shutdown to get as much oil as possible up into the tank.

Also, with radial engines, we need to pull the prop through before staring up to clear any oil that has run down and is sitting in the exhaust valves. Some Yaks have got a drain tap to do this more efficiently.

If it’s left it can cause hydraulic lock which can bend the con-rod and cause engine failure. The cans over the exhaust stubs help to catch any oil and stop it from making a mess on the ground or down your flying suit!

Re: the air system. It might seem archaic, but it is a very efficient and normally robust way of dealing with the very low temperatures in Russia. Air is used for starting the engine, brakes, flaps and undercarriage.

A normal battery starter system wouldn’t cope with the cold conditions, hydraulic fluid freezes – but air doesn’t!

A small battery is needed for the ‘shower of sparks’ starter, but the load is taken by the air starter.

The air system needs to be purged at the end of each sortie – via the ‘snot’ valve – this stops a mixture of air, oil and water creating an emulsion (very like margarine) and blocking the system.

The Yak I fly has been having compressor problems, but we have been flying it by topping up the air from an external bottle. It takes about two minutes. As the brakes operate off a lower pressure circuit, there is no problem taxying when the pressure is getting a bit low.

Also, having the aircraft clonking and hissing just adds to its character.

YR 😀

Right, if this doesn’t work, i’m going to bed.

Ah !! finger trouble, meant to post this one.

Are you sure they hadn’t shoved old oil bottles up the exhausts like they do at my local flying club? I was told this was to catch the leaking oil but I’m not so sure how much would leak out of the exhausts if any and whether this would be an effective way of catching it. It’s more likely to stop furry things getting in there. We have a Marder (German ferret/pine marten) problem around here. They’ed have to be pretty acrobatic though. See below. (Yes, I know it’s a slightly different Yak)

Originally posted by Kenneth
This archaic pneumatic system is one reason why I have no desire to be involved with Yaks, regardless of how much I would win in the lottery (sorry for stepping on some people’s toes…).

I wouldn’t worry about stepping on peoples’ toes.

It’s your loss, not theirs.

Moggy

This archaic pneumatic system is one reason why I have no desire to be involved with Yaks, regardless of how much I would win in the lottery (sorry for stepping on some people’s toes…).

I’m glad this didn’t happen when I was putting fuel into this thing at Woodchurch.
Yak 50’s and 52’s don’t seem to be the aircraft to have at the moment. Lets hope the current issues with them can be resolved and the owners can get back to enjoying them rather than waiting for the next thing that the CAA can throw at them.

I had heard of the other incident, sounds very unlucky, lets just hope the damage can be repaired quickly.

Well guessed guys!

The aircraft was started and run up normally.

As it taxied forward for fuel, the compressed air bottle exploded.

The blast forced the throttle fully open and the Yak nosed over, shredding the props.

Corrosion of the air bottle is the likely culprit, as it split in two.

The aircraft had recently been in Sweden as part of the Aerostars team. It was lucky that this didn’t happen in the air and over the sea.

Looks like it will be another expense for Yak owners to get their bottles pressure tested – we don’t want this to happen again.

YR

Yak 11 Fan: I don’t know if you heard the news that Angie Soper’s Yak nosed over at Little Gransden when it returned there after attending the Flypast Fly-in at North Weald. There had been a shower in the meantime, the grass was wet and it’s not a long runway. She got out OK, but that could have been very nasty indeed.

So no Yak 11 for Sunday. It’s been a bad year hasn’t it.

you let my missus near it didnt you!!

Pilot forgot to ‘snot’ the pnuematics before start up, something got blocked, pnuematic system overpressurised then exploded?

Moggy

If it’s not pneumatics going bang, it doesn’t have a cartridge start system does it?

Nitrogen or whatever used in the air start system which when it went off put the aircraft on its nose?

You’re getting warmer!

YR

Some thing to do with pneumatics? I know there are a lot of wierd systems on Yaks but is the prop controlled pneumatically?

Those concrete tie down blocks look to be a little suspicious, did one if them somehow end up embeding itself into the aircraft?