PPRuNe Forums

PPRuNe Forums (https://www.pprune.org/)
-   Rotorheads (https://www.pprune.org/rotorheads-23/)
-   -   Question from a mere spotter (https://www.pprune.org/rotorheads/633527-question-mere-spotter.html)

The Nr Fairy 29th Jun 2020 09:29


Originally Posted by ShyTorque (Post 10824221)
The problem here is that two helicopters are being forced to fly in close formation with each other. They are so ugly that they repel each other, so sometimes the shaft breaks.

The shaft certainly has broken on an RAF Chinook, at Odiham. Thankfully the aircraft was in the low hover and the occupants escaped intact. Mind you, everything else broke, too. The pilot told me that after it fell to the ground like a railway carriage, he naturally reached up to shut the engines down and the engine controls had departed, along with the cockpit roof, which was also missing.

Less happily, a fatal to a British Airways Chinook in 1986 - https://en.wikipedia.org/wiki/1986_B..._Chinook_crash, and the report available at https://www.gov.uk/aaib-reports/2-19...-november-1986

And to a US Army Chinook in Germany too in 1982 - http://www.chinook-helicopter.com/hi.../74-22292.html

nowherespecial 29th Jun 2020 11:36

Also worth remembering that most things are easy to do in aviation when your power margin is as big as the Chinook.... Spectacular aircraft to fly, fully laden but mind blowing to fly when empty of pax and kit.

Thud_and_Blunder 29th Jun 2020 12:00

It's the only helicopter I've operated with a max rate of climb limit (3000fpm, ISTR), apparently due to a 3-axis shuffle which developed during test-flying when that RoC was exceeded. As the aerodynamicists were unable to provide an explanation, a limitation was imposed.

As for the aircraft at Odiham decoupling on lifting to the hover (remember it well, it was on the first day of Chinook groundschool for my course) - at least the Chinook had fuel disconnect switches available in the cabin (as operated by the good Sqn Ldr as he departed the airframe). I believe that a CH53/ Sikorsky S65 variant that suffered a heavy landing which caused the disc to droop so far as to turn the cockpit into a cabriolet had no such feature, which meant that the aircraft had to be left turning and burning until the fuel supply was exhausted.

Fareastdriver 29th Jun 2020 12:06

I didn't know about the Odiham Chinook probably because it wasn't fatal.

Mannheim was a result of the forward pinion bearing seizing which led to the transmission failing. Rumour has it that Elfinsafety stopped the overhaul team used 'dangerous' 3,000 p.s.i. to clear the oilways of the walnut grit used to clean them. Lower pressure didn't work as well so it eventually blocked it.

The Sumburgh on was where a solid gear was replaced with a lined one that could be overhauled more cheaply. Unfortunately it wasn't trialled over the North Sea so salt laden air got in and corroded the joint leading to a failure of the forward gearbox.

You can make helicopters 100% safe but then you get slammed by a bus on the way to work.

212man 29th Jun 2020 13:33


Originally Posted by Thud_and_Blunder (Post 10824421)
As for the aircraft at Odiham decoupling on lifting to the hover (remember it well, it was on the first day of Chinook groundschool for my course) - at least the Chinook had fuel disconnect switches available in the cabin (as operated by the good Sqn Ldr as he departed the airframe). I believe that a CH53/ Sikorsky S65 variant that suffered a heavy landing which caused the disc to droop so far as to turn the cockpit into a cabriolet had no such feature, which meant that the aircraft had to be left turning and burning until the fuel supply was exhausted.

That was an S61 on a vessel in the East Shetland Basin - I think the tail wheel slipped off the deck (or they missed it) and the instinctive forward cyclic took the roof off. The pax and co-pilot stayed on the vessel and captain went and sat on the water until the fuel ran out. There are photos online of it (but can't find them)

Gordy 29th Jun 2020 15:42


Originally Posted by Thud_and_Blunder (Post 10824421)
It's the only helicopter I've operated with a max rate of climb limit

The Bell 407 has a max rate of climb of 2,000 fpm.

Ray_Y 29th Jun 2020 16:14

I would like to thank for this nice discussion.

Very nice Chinook background and hilarious content


All times are GMT. The time now is 11:54.


Copyright © 2024 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.