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-   -   Underslung Koala fail (https://www.pprune.org/rotorheads/661190-underslung-koala-fail.html)

UnderASouthernSky 31st August 2024 08:45

Underslung Koala fail
 
This lift does not look stable from the word go. Interesting to know if the release was intentional.

https://asn.flightsafety.org/wikibase/419086

https://www.indiatoday.in/india/stor...235-2024-08-31


Nubian 31st August 2024 10:20

The article says it was dropped intentionally.

Clowns….

[email protected] 31st August 2024 10:34

It was clearly becoming dangerously unstable - I understand why they dropped it.

However, careful loading of the underslung aircraft might have helped - but it was never going to fly fast underslung. A drogue attached to the tail may have helped.

All in all a pretty pi** poor demonstration of how to undersling a helicopter.

Hughes500 31st August 2024 13:34

Crab

You are right on there, the muppet flying the Mil was going about 40 kts too fast. Lifted an Enstrom ( 800Kgs ) off a Welsh mountain with a 350 VNE was at best 30 knots.

highrpm 31st August 2024 15:33

Never done underslung - would a drogue chute not require a certain amount of forward speed to have any effect 40kts or so(?), and at low speed on a fuselage without an effective drogue would the downwash not cause an almost immediate spin considering the vertical stabiliser at the end of the tail boom being susceptible to any sideways airflow?

Cyclic Hotline 31st August 2024 15:52

What a joke! That 119 might have suffered some damage the first time it crashed, but nothing like that second one. This is the most spectacular example of a helicopter lawn dart I have ever seen. Clueless. And yes, anything attached to the tail would have kept it flying straight - tree branches work extremely well.

SASless 1st September 2024 00:54

High RPM,

Drogue chutes work well usually...helps if they have a swivel between the chute and aircraft otherwise the chute can spin and eventually collapse.

Within the first 100 feet of heigh gain and about just above ETL....it was apparent that was a grossly mis-rigged load that was not going to ride well at all.

KiwiNedNZ 1st September 2024 01:56

Its India - what else can you say :8

Nubian 1st September 2024 09:18


Originally Posted by SASless (Post 11726823)
High RPM,

Drogue chutes work well usually...helps if they have a swivel between the chute and aircraft otherwise the chute can spin and eventually collapse.

Within the first 100 feet of heigh gain and about just above ETL....it was apparent that was a grossly mis-rigged load that was not going to ride well at all.

The normal way of lifting a single rotor helicopter, is with one sling attached to the MR-hub (quite obvious why for most)
This however looks as it is being strapped with multiple straps, and I only guess they were attached to the crosstubes, as I can’t think og other points to attach lifting straps. Then the balance of the load is above the liftingpoint and it will be completely unstable.

At the 9sec mark, you can see what looks like a strap failing.


helispotter 1st September 2024 12:14


Originally Posted by Nubian (Post 11726973)
The normal way of lifting a... helicopter, is with one sling attached to the MR-hub...
This however looks as it is being strapped with multiple straps,... attached to the crosstubes... Then the balance of the load is above the liftingpoint and it will be completely unstable.

At the 9sec mark, you can see what looks like a strap failing.

I don't see a rotor mast (or gearbox) on the AW119 anymore. Perhaps they had first attempted to make repairs at the 'emergency landing' site before they concluded it needed to be lifted out for repairs. Then they didn't have the preferred lifting point anymore so had to use a work-around? Bad move.

Yes, I also see something flick up in first video. But load was already unstable before that and it didn't seem to lurch after that event. But if a sling failed, they were probably down to three slings still attached so an even less stable arrangement.

In second video the AW119 is doing 'crazy stuff' before it is released! No surprise they decided to release it!

What is the 'vapour trail' that is streaming from it as it plunges into the valley? Remaining fuel on board somehow emerging??

helispotter 1st September 2024 12:31

Curious about sling loading of helicopters, I googled for images. This site shows a variety of sling loads carried by Chinook. Interesting that Blackhawk cases haven't been slung from their mast. There must be a reason for that:

https://www.chinook-helicopter.com/s...ad_Weight.html

Lynx sling load seems to show several "streamers" attached. They don't seem to be chutes. Perhaps they are instead to allow the behaviour of sling load to be monitored more carefully?? Or do they serve to damp out any oscillations?

601 1st September 2024 13:06


An Australian Chinook transports an old Mirage fighter aircraft to Tyndal Air Force Base for restoration in the Northwest Territories, circa 2001.
I didn't know that a Chinook had that range!!

helispotter 1st September 2024 14:09


Originally Posted by 601 (Post 11727089)
I didn't know that a Chinook had that range!!

601: The caption text was fairly scrambled but I worked out this must have been A3-36 taken from Darwin to Tindal (Northern Territory) as a slung load. Around 280 km or 150 NM, see:

https:/www.darwinaviationmuseum.com.au/mirage-1110/

But at least the Mirage had a safer ride than the AW119. That said, it had previously also been a 'dart' as the linked description reveals.

Update: Oh, I was slow to get your joke! :-)

TRC 1st September 2024 17:41


Originally Posted by helispotter (Post 11727078)
Curious about sling loading of helicopters, I googled for images. This site shows a variety of sling loads carried by Chinook. Interesting that Blackhawk cases haven't been slung from their mast. There must be a reason for that:

https://www.chinook-helicopter.com/s...ad_Weight.html

Lynx sling load seems to show several "streamers" attached. They don't seem to be chutes. Perhaps they are instead to allow the behaviour of sling load to be monitored more carefully?? Or do they serve to damp out any oscillations?

I would say that they are handling lines.

megan 2nd September 2024 02:56


must have been A3-36 taken from Darwin to Tindal
A3-36 made a safe landing in the Darwin mud flats after the pilot had ejected at 1,000 following engine failure in the circuit, even streamed the drag chute, now resides in the Darwin museum. I assume the Chinook lift was to Tindal for refurbishment prior to return for museum display. The aircraft had previously been recovered from the mud flats to Darwin airport by an A model Chinook.

https://cimg9.ibsrv.net/gimg/pprune....f904bbf50a.jpg

Chinook lift at Darwin for Tindal, flight took two hours


SASless 2nd September 2024 12:46

Megan,

A Model Chinooks have a "sharp" tail fin.....B Model and forward have the "Square" tail fin.

Unless my old eyes are lying to me the Chinook in the video appears to be not an A Model....for what it is worth in the 75 Squadron video.

The reason for the design change was by squaring the tail fin it provided a real improvement in yaw stability....something akin to adding over thirty feet of Fin to achieve the same improvement.

It was among the best improvements in handling that has been made. The A Model was very lively in yaw.....with two Rotor Heads arguing about which was going to lead in the dance.

I believe the RAAF started with C models and then progressed to D's and F's.

I would give three feet of my Trigger Finger to have flown the MH version of the Chinook with all of its capability with the F Model probably. being a real Horse to ride as. well.


From Wiki....


The Australian Defence Force has operated Boeing CH-47 Chinook heavy-lift helicopters for most of the period since 1974. Thirty four of the type have entered Australian service, comprising twelve CH-47C variants, eight CH-47Ds and fourteen CH-47Fs. The helicopters have been operated by both the Royal Australian Air Force (RAAF) and Australian Army.

An initial order of eight Chinooks for the RAAF was placed in 1962, but soon cancelled in favour of more urgent priorities. The Australian military still required helicopters of this type, and twelve CH-47C Chinooks were ordered in 1970. The CH-47s entered service with the RAAF in December 1974. The eleven surviving Chinooks were retired in 1989 as a cost-saving measure, but it was found that the Australian Defence Force's other helicopters could not replace their capabilities. As a result, four of the CH-47Cs were upgraded to CH-47D standard, and returned to service in 1995 with the Australian Army. The Army acquired two more CH-47Ds in 2000 and another pair in 2012. The CH-47Ds were replaced with seven new CH-47F aircraft during 2015, and another three were delivered in 2016. A further four CH-47Fs were ordered in 2021, with two being delivered that year and two others arriving in 2022.

212man 2nd September 2024 15:58


The reason for the design change was by squaring the tail fin it provided a real improvement in yaw stability....something akin to adding over thirty feet of Fin to achieve the same improvement.
​​​​​​​Kamm tail

megan 3rd September 2024 04:41


Unless my old eyes are lying to me the Chinook in the video appears to be not an A Model
Correct SAS. , the Mirage sat at the airport for quite some time until the Chinook in the video lifted it to Tindal, in fact looking up the records we never operated A models, so the source of that info is incorrect, we operated C, D and F as you rightly found. Don't believe anything you read and only half of what you see.


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