Coulson 737 Fireliner Accident near Ravensthorpe Western Australia 6th February 23

[Rotorwork]

Reports coming in of a 737 crashed in Western Australia,  Other firefighting aircraft from nearby, doused the burning 737 & pilots were saved. 
 

https://7news.com.au/news/disaster-and-emergency/firefighting-aircraft-crashes-in-was-great-southern-c-9671802

Edited February 6, 2023 by Rotorwork
Additional information

[BrendAn]

Coulsens have had a bad run in Australia, glad this crew survived.

[onetrack]

Not a bad place to crash, not many big trees, lots of mallee. They must have slowed her right up before they hit the deck. Glad to hear the crew got out O.K.

 

https://www.abc.net.au/news/2023-02-06/water-bomber-crashes-fighting-wa-bushfire-two-people-hospital/101938070

[Carbon Canary]

...and of course the channel 7 stock footage shows a throttle quadrant with four throttles.

[onetrack]

It looks like she's well and truly toasted. Instead of putting out the fire, she's made the fire worse! Very cool of them to land right near a good access track, Fitzgerald National Park is huge, and access tracks/firebreaks are a long way apart!

 

That low mallee scrub is the most forgiving vegetation for a forced landing, and also very fortunately, the terrain is flat, to low undulating.

 

I hate to think what this companys insurance premiums are like. They're starting to make cropdusters look risk averse.

 

 

 

Edited February 7, 2023 by onetrack

[facthunter]

Other water bombers "doused" the Plane I think.  Nev

[onetrack]

FOR SALE:  B737, only 2 owners, ran well when last used, may need some maintenance to get running again. As-is where-is, purchaser needs to bring own trailer. Call Wayne Coulson on 1800-RSFIREBOMBER

[Litespeed]

When I first heard a 737 went down, my first reaction was........another maintenance free Qantas flight.

 

Obviously Alan Joyce was quick to repaint the tail.

 

 

Glad pilots are Ok.

[facthunter]

A rather dramatic way to end a day's work.. Be interested to see what happened there..   Nev

[BrendAn]

12 minutes ago, facthunter said:

A rather dramatic way to end a day's work.. Be interested to see what happened there..   Nev

They said it clipped a hill then went down on the news last night.. if you can believe a reporter.

[onetrack]

Brendan, the comment was directly from Angus Mitchell, CEO/Chief Commissioner of the ATSB, so it carries some weight. His actual comment was "it does look as though it's potentially clipped the ridge line, and has pancaked down."

 

So the ATSB appear to have evidence of the aircraft contacting either vegetation or terrain, prior to crashing. The experts are weighing in again with pretty useless conjecture, with one "senior aerospace design" lecturer stating there's major similarities to the Coulson C-130 crash last year. 

 

AFAIC, she's talking rubbish. She's using radar data for her opinion, and the radar data at very low level in that region where the B737 crashed, would not be the same quality as radar data from within modest proximity of a major airport.

There's little similarity in the crashes. Both weather conditions and terrain are vastly different between the C-130 crash, and the B737 crash. The C-130 was experiencing vicious gusting over steep ridgelines and a tailwind component as well.

The C-130 dropped a wing in a classic stall and effectively cartwheeled, invoking massive airframe destruction via contact with the ground.

 

The B737 has pancaked, no indication of any wing drop, so the pilots were still able to keep the wings level until she stopped. The fuselage and wings of the B737 were intact when she stopped moving. The wind component for the B737 was a headwind, thus assisting in crew escape from the resultant fire caused by fuel tank disruption.

 

There are reports that two HD cameras on other aircraft captured virtually the entire event, so that would be interesting to see, if they ever become publically available.

 

There's virtually nothing left of the fuselage, I had no idea a B737 could burn so completely. I guess the dry local Mallee scrub provided adequate fuel to ensure a full burn.

 

https://www.abc.net.au/news/2023-02-08/similarities-between-boeing-737-and-black-summer-fires-crashes/101942324

 

Edited February 8, 2023 by onetrack

[kgwilson]

Wow, the heat must have been really intense. The early fire photo showed the fuselage completely intact and fire free from the nose to the wing root. Those pilots were really lucky to be able to get out quickly. The empenage is all that is left. Just amazing. 

[onetrack]

Fitzgerald National Park is quite a spectacular Park visually, but the only terrain that poses a real danger to low-flying aircraft, is West Mt Barren, which is in the SW of the Park. The B737 crashed in the North Eastern part of the Park, and quite a way inland.

 

The Park terrain is largely flattish to moderately undulating inland, become more rugged within a few kilometres of the coast. There are a number of low ridges with cliff faces (locally known as "breakaways") within the Park.

 

There are numerous modest-size ravines close to the coast, and a few modest outcropping hills, none of which are any more than around two to three hundred feet high. But around West Mt Barren, the terrain is definitely a lot more rugged, and West Mt Barren has an elevation of 372 m (1,220 ft).

 

There is also another lower peak, East Mt Barren, which is right on the coast, on the Eastern edge of the Park. East Mt Barren is 311 m (1,020 ft), and rises up steeply from the nearby undulating terrain.

 

Both peaks are clearly visible in the good weather conditions the fire teams were working in, on the day of the crash, and I would not expect either peak to have any effect in the crash site region, on the largely prevailing SE/E winds there, at this time of year.

 

The Park is home to a very large range of flora and fauna diversity, and also contains a number of endangered species of both flora and fauna. 

 

https://en.wikipedia.org/wiki/West_Mount_Barren#/media/File:West_Mount_Barren_1.jpg

 

https://www.fitzgeraldfriends.org.au/the-park

 

https://exploreparks.dbca.wa.gov.au/park/fitzgerald-river-national-park

 

https://www.google.com/maps/place/34°12'59.0"S+119°25'58.0"E

 

https://www.google.com/maps/place/East+Mount+Barren/@-33.9447757,119.7018838

 

Edited February 8, 2023 by onetrack

[Litespeed]

5 hours ago, BrendAn said:

They said it clipped a hill then went down on the news last night.. if you can believe a reporter.

The reporter was heard to say, " this Cessna was water bombing and ran out of air"

[Thruster88]

Pic showing the wings level touchdown ground scar engines first. 

 

[onetrack]

This a typical "breakaway" ridge (photo below) within the Fitzgerald National Park that the B737 is likely to have clipped. Usually only about 60 to 100 feet high, rarely reaching 120 feet.

 

I was surprised to find the weather records show that it was an unusually hot day for this area. The nearest weather recording station is at Jacup, just outside the Park, to the NW.

Jacup recorded 36.8° maximum that day, and it was still 35.8°C at 3:00PM, just over an hour before the crash happened.

 

There was a big pool of hot air over the Park both on Sunday 5th and Monday 6th, drawn in from the central N of W.A., via a fairly strong hot Northerly wind, that was averaging 28kmh (15kts) and with gusts to 46kmh (25kts), just after 9.00AM.

By 3.00PM, the tip of a cold front from the South had swept through the Park, and the wind direction had changed to a Westerly at 30kmh (16kts).

 

http://www.bom.gov.au/climate/dwo/IDCJDW6058.latest.shtml

 

So I don't think vicious wind gusts, or wind rotor effect over the ridge, would have had any impact on the aircraft, as regards crash conditions.

I would expect the relatively high ambient temperature (exacerbated by flying close to the hot ground) might have played a part.

Perhaps clipping the mallee trees on the ridgeline was caused by a misjudgement of available lift in the high ambient temperature conditions, at near stall speed - and the resultant drag of the vegetation on the fuselage was just enough to slow the 737 down, and make her pancake onto the valley floor below.

As I understand it, spool up lag with a jet engine can be several seconds, and any extra thrust required, when it's obvious you need it, comes too late, at very low level.

 

 

[facthunter]

IF you're well above idle, the lag doesn't happen. On such engines it's required you spool them up a bit at 3000' on a normal let down. Nev

[facthunter]

Some engines aren't affected at all It depends on the engines flow characteristics and the Flight Idle setting. You also have to consider the pressurisation system particularly at higher altitudes.. Air for that is bled from the axial flow compressors and idle won't do it.   Nev

[BrendAn]

how would this affect coulsons business model, losing this aircraft and the other one with its crew. they would have trouble keeping insurance assuming they have it at all in such a high risk venture. would they be self insured. thats what transport companys do when the premiums get too big.

[rankamateur]

This was one of six 737 in their fleet so if the premium was more than 17 percent they would still be in front.

Edited February 9, 2023 by rankamateur
Wrong word

[facthunter]

I have expressed the view before that swept wing Jet airliners are not designed to stooge around at low speed and low levels in HOT and oxygen "starved" air.  The type of control applications required in  turbulence would kill performance by creating drag. ALL ailerons and differential spoilers. The sweepback causes "dutch roll" effects that must be counteracted to retain full control. That is mainly achieved by lift loss and lots of drag on the rising wing. Ther's also the question of just how strong the wings are in the flapped configuration.. They are not built that strong in the first place and are old airframes. Nev.

[onetrack]

I'm guessing they'll be re-writing the Coulson pilot manuals right about now, as regards low-level flight and at speeds close to the stall. I think Nev is spot-on, the Coulson pilots seem to be too keen to get down close to the fire, and they are probably getting a surprise at the level of sink from the swept wing at low speeds, and in hot conditions. The B737's whole design is centred around moving a pile of pax at 0.78 mach, that's where they spend 95% of their time.

 

When you redesign the aircraft to carry a huge tank of compact weight retardant in one small area of the fuselage, and then attempt to operate at as slow a speed as possible, you're going against every single original design feature of the B737.

The other angle too, is the level of power loss from a jet engine in hot conditions. That ISA + 20°C can apparently cause about a 10% reduction in power, and coupled with the loss of lift (1% loss for every 3°C above ISA is the figure I saw), it all adds up.

 

Edited February 10, 2023 by onetrack

[facthunter]

Even the stagnant hot air over the end of a runway sometimes causes a quite bad landing in a jet. A mate of mine had his Ceres fall into  a cotton crop in a night op where there was a patch of warm air. The Fire work could also have oxygen depleted air which will certainly reduce the Power available. I once got stuck on a road riding a motorbike with fire down both sides and the engine nearly stopped 2 or3 times in about a Km of road. THAT was due to reduced oxygen.   ,Nev

[RFguy]

Not to mention the DA effect  from say, 60-70 deg C fairly widespread air temperature  100m above a fire easy.

[Old Koreelah]

12 hours ago, facthunter said:

The Fire work could also have oxygen depleted air which will certainly reduce the Power available. I once got stuck on a road riding a motorbike with fire down both sides and the engine nearly stopped 2 or3 times in about a Km of road. THAT was due to reduced oxygen.   ,Nev

Nev that’s a point most of us never consider. I once risked a short cut across Lake Liddel. Right over the middle of that wide expanse of water the plurry engine spluttered- just enough to give me a scare. Seems I had flown through the invisible plume of CO2 downwind of Liddel’s chimneys.