Propeller hunting - somewhere in Sydney's south west

[Brumby]

Around midday today on approach to Sydney Airport....

http://www.abc.net.au/news/2017-03-17/rex-flight-forced-into-emergency-landing-after-losing-propeller/8364218




I don't doubt there are going to be a lot of questions asked....

Edit: Title updated - apparently the location for the propeller is not as I first heard.

[Cubdriver]

    Yeah, it's generally a bad thing when one of the fans falls off while the flying machine is airborne.  The good thing is that whatever happened, it appears to have separated cleanly.  Things get very ugly when only one blade parts company - it gets a bit shaky.

Sounds like the pilots handled it all in stride, and it's always nice to see everyone walk away unhurt when something like this happens.

-Pat

[nfmax]

Propellers are designed to separate cleanly in the event of a catastrophic failure, as this is survivable. If it fails to separate, and takes the engine with it, the weight and balance change will generally make the aircraft unflyable.

[boffin]

Nice is it managed to completely avoid the fuselage, it's never good when it strikes the airframe

This is what you don't want....

http://edmonton.ctvnews.ca/propeller-of-flight-forced-to-land-in-edmonton-crashed-through-window-1.2093562

[dave_k]

ABC News reported that the prop detached at approximately 6000 feet.
Looking at the flight track, that was somewhere over Mosman...

[MadTux]

Let me guess, aluminum prop blades, metal fatigue and a crack at the base of one of the blades.
Blade goes byebye and the inbalance of the prop causes it to separate. Luckily no parts crashed into the fuselage.

You probably better avoid seats that are on the same plane as the prop rotation plane in these aircrafts

[MarvinTheMartian]

Haven't found the prop as yet. 

It's good that the plane landed safely without injuries, but having not found the prop doesn't rule out possible injuries/death on the ground.

Hopefully this has not occurred.   

[Dinsdale]

So that's what cracked Dave's solar panel!

[rrinker]

 Darn it, that is EXACTLY what I was about to say as I scrolled through this.

[Neilm]

A few years ago I saw a programme on aircraft crashes / emergancies. This reminds me of one in the 80's where the propeller came off an old 4 engine aircraft and chopped a hole in the airframe. The aircraft used wires to move the control surfaces and some of these were damaged, alone with the thrust and pitch control of the engines. As the stewardess interviewed remarked - it was unnerving to step out of the cockpit and realise that looking down she could see the sea.

The aircraft had to fly a few hundred miles to find somewhere to land as with damages engine controls they could not make a proper approach. The pilot turned off the engines as it touched down. It landed safely with no casualties.

[boffin]

A few years ago I saw a programme on aircraft crashes / emergancies. This reminds me of one in the 80's where the propeller came off an old 4 engine aircraft and chopped a hole in the airframe. The aircraft used wires to move the control surfaces and some of these were damaged, alone with the thrust and pitch control of the engines. As the stewardess interviewed remarked - it was unnerving to step out of the cockpit and realise that looking down she could see the sea.

The aircraft had to fly a few hundred miles to find somewhere to land as with damages engine controls they could not make a proper approach. The pilot turned off the engines as it touched down. It landed safely with no casualties.

Lockheed Electra in Alaska, specifically this incident https://en.wikipedia.org/wiki/Reeve_Aleutian_Airways_Flight_8
as featured in Season 12 Ep 1 of the Canadian series "Mayday" (may be called something else in your jurisdiction)

[SeanB]

Military aircraft generally have a nice yellow ring on the outside and inside of the fuselage, where the blades will come through in case of failure. I generally used to sit a little rear of them in a C130, though being at the wing root did have a big drawback of sitting right on top of the Main and Aux hydraulic pump, which ran pretty much all flight. Of course being at the CG also allowed you to do interesting things, like holding a bottle of cooldrink and making it sit level in the bottle during turbulence, even with the bottle itself doing strange gyrations in the interior. Then getting out a sandwich and eating it, and having a few plastic "convenience" bags around for quick deployment to those who were more likely to be airsick.

Was a lot more interesting on the C47, there you did not fly over the thunderstorms, but through. Go on a flight one day and got to the C47 destination, then went to the next airport ( from military to commercial) and got on a regular 737 flight. Shorter flight time, but longer distance. As we take off they announce there will be severe turbulence, and they will only serve dinner on request from individual pax. I was sitting in the back row, having bought a standby ticket on the first flight, and ordered the meal. Stewardess enquired if I was sure, it would be very bumpy. Replied I just flew through this same storm at 6000ft, and at 25000ft in this plane there was nothing it could do that would worry me. Just had to hold the real plate, real cutlery ( got the first class meal, there were so few who wanted a serving) and glass of wine onto the seat back, so they did not fall off during the meal with the mild turbulence.

[Brumby]

The prop has been found - by a Police helicopter on routine patrol.  The crew noticed tree damage and had a closer look.

It was located in bushland about 20m or so from The River Road in Revesby.  Apparently, it landed only about 100m from houses.

From what I can conclude about the exact location - this bushland is part of the nature reserve around the Georges River to the south.  To the north is typical suburbia.  Houses everywhere.

[BradC]

The prop has been found - by a Police helicopter on routine patrol.  The crew noticed tree damage and had a closer look.

I was hoping it'd turn up. Having both ends of the shaft should make the failure analysis easier to complete.
No harm no foul. We like happy endings.

[Brumby]

No harm no foul.

Maybe ... but considering how close it came to houses - it's like have a gun fired in your direction where the bullet misses you, but you feel it go past your ear.

Very lucky.

[EEVblog]

Let me guess, aluminum prop blades, metal fatigue and a crack at the base of one of the blades.
Blade goes byebye and the inbalance of the prop causes it to separate. Luckily no parts crashed into the fuselage.

Nope, all 4 blades found  intact and attached on the ground.
http://www.abc.net.au/news/2017-03-21/propeller-found-in-bushland/8373548

[EEVblog]

Propellers are designed to separate cleanly in the event of a catastrophic failure, as this is survivable. If it fails to separate, and takes the engine with it, the weight and balance change will generally make the aircraft unflyable.

This guy landed without a wing!


Granted, it was an F-15

[amyk]

There's a very close picture of what's left of the shaft here:
http://avherald.com/h?article=4a651f6e&opt=0

The shaft is hollow.

[timb]

Propellers are designed to separate cleanly in the event of a catastrophic failure, as this is survivable. If it fails to separate, and takes the engine with it, the weight and balance change will generally make the aircraft unflyable.

This guy landed without a wing!


Granted, it was an F-15

Yeah, the only reason he was able to land is because he kept his speed up. Well, that and a bit a luck. As long as there's sufficient thrust, you can keep the plane level with very few control surfaces (think: rocket).

The problem comes when you try to land. You land with too much speed and the landing gear break (or go through the body of the plane), the tires explode, you run out of runway, the hook rips the plane in half (though technically that shouldn't happen as they're designed to fail safe at a certain stress point), etc.

Too little speed and you lose control and spin into the ground or just fall out of the sky.

There were some very specific circumstances that came together to allow that landing. Like he says in the interview, had he know the wing was gone, he'd have ejected immediately.

Growing up my best friend's dad was an F-15 pilot and later was a training instructor. I remember talking to him about the above incident. He would have ejected too!)

[TerraHertz]

The prop has been found - by a Police helicopter on routine patrol.  The crew noticed tree damage and had a closer look.

It was located in bushland about 20m or so from The River Road in Revesby.  Apparently, it landed only about 100m from houses.

From what I can conclude about the exact location - this bushland is part of the nature reserve around the Georges River to the south.  To the north is typical suburbia.  Houses everywhere.

Huh. On it's way to my house. That explains the number of helicopters flying around here today.
Incidentally, the only bushland that could be, is the Georges River National Park at the Sth end of River Rd. Which means, the prop not only just missed houses, but it also just missed ... Sydney South. One of the two Transgrid switch yards that handle ALL the electric power coming into Sydney. It would have caused a fine mess if it had impacted there.
Can't have been more than 500 m from the switch yard.

[SeanB]

That crack is a classic fatigue crack. Either they have been pushing the NDT testing out too far, not doing it correctly or not checking the whole shaft out of the aircraft. That should have been found a while ago, that corrosion on the crack is not new, but the failure area is nice and shiny. Might need a slightly thicker shaft, as a redesign, or a change to inspection level for this area. I strongly suspect there are many more with this crack in there, if 2 have failed.

[james_s]

Well there's that old saying about hindsight. After the accident occurs it's easy to say that the problem should have been found, but given the complexity of an aircraft that can be a daunting task. Fortunately this sort of failure is quite rare.

[boffin]

From the photos on avherald (which show a guard rail), and news items that say it landed by River Road and Sandakin Road, I think that would place it right about here:

https://www.google.ca/maps/@-33.9688643,151.0150542,3a,75y,106.54h,94.49t/data=!3m6!1e1!3m4!1sUkwFrwJfEJ8yQ-w1BQMX-g!2e0!7i13312!8i6656!6m1!1e1?hl=en

[TerraHertz]

From the photos on avherald (which show a guard rail), and news items that say it landed by River Road and Sandakin Road, I think that would place it right about here:

https://www.google.ca/maps/@-33.9688643,151.0150542,3a,75y,106.54h,94.49t/data=!3m6!1e1!3m4!1sUkwFrwJfEJ8yQ-w1BQMX-g!2e0!7i13312!8i6656!6m1!1e1?hl=en

This afternoon I knew I'd be driving past there, so took a camera with me. Unfortunately the weather chose that half hour to dump buckets, so although I stopped right there at your google maps location, I couldn't see any sign of official propeller-pickup vehicles being around recently, and didn't want to go bush bashing.

Btw, that gray thing in the upper right of the photo, isn't a road guard rail. It's some part of the helicopter from which the photo was taken. Observe the blur and overlaying closely. The object is above the trees. Also the bush isn't where your streetview was pointed - that bit of bush is completely invaded by introduced climbing vines. While the bush in the avherald photo has no vines. Lots of the bush around there in the park looks like the avherald photo. I was hoping to find recent wheel tracks or something on a fire access road, to follow to the impact site. Won't be anything there now, but still interesting.

[Halcyon]

You missed them. Police and ATSB picked it up this morning :-)

[Brumby]

By helicopter lift.

The Pol Air chopper with harness and propellor at a local sportsfield after retrieval.


That's why there wouldn't have been any tracks going to the landing site - other than a few people on foot.

[TerraHertz]

Ha, I know that field.

Anyway, I'd assumed it would be gone, and don't care. Just curious to see if I can find the impact spot. Partly to see how close it was to Sydney Sth switchyard. It's really amusing that the one time anything like this happens (apart from light place crashes around Bankstown airport) the part lands so close to such a critical piece of infrastructure.

I gather from the heli-lift, that it wasn't close to roads.

Maybe I'll try again if the weather is suitable. I notice the forecast is for another week of showers.

Edit: They are lucky the blades are still in feathered position. The image of a propeller suspended by rope under a helicopter suggests a rather comical development. Very Wile-e-coyote.

[TerraHertz]

This is better in a post by itself, so, double post, sorry.

Speaking of aircraft maintenance that isn't all one would hope for, I have a story to tell.

I like dumpster diving. Some years ago I was in Hurstville and spotted a large skip on the street out front of a house. It turned out to be full of aviation-related stuff. While I was looking, a lady came out of the house and we chatted for a while. The skip contained her deceased husband's collection of memorabilia. He'd been a pilot, and ran a small air charter business, as well as being involved in air accident investigations. While we were talking I was still fishing in the skip (with her permission) and had come across a couple of turbine sections from a small jet. (pics below) She told me their story.

They'd been in a small charter jet her husband owned and flew. He'd been complaining to the mechanics, repeatedly, that an engine was acting funny, not developing the thrust it should. The maintenance guys supposedly checked it out several times, each time saying it was fine.

Finally he insisted, and refused to fly it any more until the engine was stripped down and inspected. This is what was found. The plane had been flying like this for quite a while, many flights. The photos speak for themselves. Does that look fine to you?

They are nice conversation pieces in my museum now. Saved from the skip, obviously.

[MarvinTheMartian]

Look fine to me TerraHertz 

What's a few corroded/missing fins between friends? 

[Brumby]

Holy crap.

[rrinker]

 Wow, wonder what it ate. Apart from the missing chunks, it all looks somewhat familiar, if small. My first post-college job was at a CNC and EDM machine shop where we made the central bearing housings as well as did the EDM drilling of the air bleed holes in the individual vanes. But for a slightly larger engine - the P&W F100 for the F-15 fighter.

[james_s]

Probably didn't eat anything, it looks like the vanes got melted. It's actually not all that hard for something like this to happen, particularly in older aircraft where the pilot has more manual control over the engine operation. The inside of a turbine engine is a harsh environment and often the turbine blades and stators operate in a gas stream that is near or above their melting point, relying on cooling air to keep them intact. You can have a hot start where too much fuel is added before the turbine has achieved sufficient RPM that melts blades.

[TerraHertz]

Barely worth mentioning, but I drove that way today when it wasn't raining. With some directions from locals, found the spot. Very definitely it, from the police tape and newly tromped path from the main track to the impact point. So just for the record, here's where it was. Very close to houses, and directly under the flight path (multiple light planes passed overhead while I was there.)

About as far from the switchyard as it could have been and still be in bush.

[SeanB]

Actually picking up a prop with a helicopter is easy, as there generally is no torque on the blade from downforce when it is slung the typical 20m below. All that down wash is held by the air, so you can lift even big items so long as the lift line is long enough.  Seen a Super Frelon lifing another helicopter ( SA330 Puma) with the rotor blades still attached, after the Puma lost lift and autorotated into a field, and saw one as well doing a heavy lift of a 15 ton ( mass not cooling capacity) cooling tower. Was strange to see an airframe I had worked on, when it was in dark earth/olive drab/pale blue livery, but the next time it was in all bright orange Mossgas livery.

Blade checks simple, just have the smallest fitter walk along them while I ( the apprentice, but tall) hold the end so it does not flex too much. Then still holding it and he goes with a ladder and flashlight on the underside.