Longreach 747 Sinking and Rescue

[Fred C]

VH-EBQ in Longreach is being lifted and shored so they can repair the nose gear stand. Some pictures and audio of the operation.

Hope the link works.:D

http://www.abc.net.au/local/photos/2012/06/01/3515970.htm?site=westqld

[callum bain]

They should of read the signs!
boggy when wet?

[Mick F]

I fly into Longreach quite a bit, and have noticed over the last 12 months that the nose wheel pad was sinking quite significantly. The soil quality around Longreach is quite poor, lot's of area's of black soil which for supporting things like roads, etc. is hopeless.

Wondering though, is the same problem occuring with the main gear? I'll have to try and sneak a look next time I'm out there.

Mick

[Bernie P]

The soil quality around Longreach is quite poor, lot's of area's of black soil which for supporting things like roads, etc. is hopeless.
To simply say that due to its colour it has no strength isn't really scientific. It may, be full of OM (organic matter) as that can be a sign of colour! Adversely, colour doesn't necessarily mean fertile either, but that’s for another day’s discussion!

Soil isn't just powdered rock, and it is the highly organised net result of the amount of time living things, inherited geology and climate have had to interact. In a conceptual formula:

S = f(cl, o, r, p, t...)

Where:-
cl = climate
o = organisms
r - relief or topography
p = parent material (geology)
t = time

The content of water-dispersible colloids (WDC) in a soil can have a major impact on soil functions, such as permeability to water and air, and on soil strength, which can impair soil fertility and workability .

Now, the most striking and obvious feature of any soil is its vertical anisotrophy; its organised into layers or horizons. The older it is, the more profound is this horizonation. In simplest form, there is topsoil and subsoil, or an 'A' and 'B' horizon. Below this, there is a 'C' horizon that for all intention purposes is bedrock. Without doing the simplest of soil tests, it would be difficult, at best, to determine as to what horizon is failing, but I would suspect it to be that of the B horizon.

Additionally, water droplet size, be it in rain drop size or from potable (or non-potable) water also causes shear strength of soil to deteriorate. Salinity, of the water and ground water, will also play its part in destroying soil structure.

I'd be keen to hear more of what’s going on up there, and I am sure both the local authorities and the QF Museum are working together in a collaborative measure, to ensure that the sink-rate of the soil is stopped!

[Nigel C]

Well, there you go. You learn something new every day around here! Thanks Bernie!

Now, why isn't my grass growing well in the sunshine but great in the shade? Is there an on-topic response you can provide for that? ;)

[Bernie P]

Thinking about this last night, and I was wondering, do the B747's have a 'nose down' attitude similar to that of the A330's? The A330's have a very pronounced nose down, where the front landing gear would be the lowest point. If the B747 has the same 'low' point being the front landing gear, then the resulting water (rain or washing water from time-to-time) could be more the cause to the creating of an apparent 'sink hole' given that the water droplet size can/would cause the soil structure worsening in a small and confined area...

[Martin Buzzell]

Good to see their all wearing hard hats and yellow vests :))

[Mick F]

Bernie,
When I refer to "black soil", I'm not referring to the colour (although, it just happens to be black when wet/damp). Out in that part of the country, 'black soil' is very unstable soil basically useless for supporting weight and doesn't tend to compact, regardless of how much you wet it, roll it, wet it, roll it.

We always had to be very careful when operating to airstrips in known black soil area's that even the smallest amount of rain (talking as little as 1mm) would make the airstrip unuseable. Even when dry, it was also very easy to dry bog the aircraft.

Mick

[Brian Noldt]

Many years ago the company I worked for had a contract to do the earthworks for the JUHI installation (Fuel Tank Farm) at Sydney Airport. One part of the contract was to prepare the fuel tank bases. After compacting the ground etc the three tanks were put on the bases and filled with water to check out that all was in order. Two passed but the third tank tilted over like "The Tower of Pisa".
The tank was emptied and lifted over onto the "spare" base
Engineers then drilled test holes and found "peat" down a fair distance, said that they had never encountered this material before. When loaded it compressed like a sponge.
The solution, "Fraki Pile" the whole tank base. This was done and the tank put back on the base.

Brian

[Fred C]

It apparently is only the nose gear. The main gear pad is ok. The theory is that there is possibly an old fuel tank underground near the nose gear. The US had several underground fuel tanks but their locations are unknown.