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Question from a mere spotter

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Question from a mere spotter

Old 29th Jun 2020, 09:29
  #41 (permalink)  
 
Join Date: Nov 2000
Location: Pewsey, UK
Posts: 1,930
Originally Posted by ShyTorque View Post
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

Last edited by The Nr Fairy; 29th Jun 2020 at 09:34. Reason: Add 1982 crash link
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Old 29th Jun 2020, 11:36
  #42 (permalink)  
 
Join Date: Jun 2005
Location: llanelli
Posts: 383
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.
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Old 29th Jun 2020, 12:00
  #43 (permalink)  
 
Join Date: Aug 2000
Location: SW England
Age: 65
Posts: 1,265
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.
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Old 29th Jun 2020, 12:06
  #44 (permalink)  
 
Join Date: Oct 2006
Location: UK
Posts: 4,867
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.
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Old 29th Jun 2020, 13:33
  #45 (permalink)  
 
Join Date: Oct 1999
Location: Nigeria
Age: 53
Posts: 4,665
Originally Posted by Thud_and_Blunder View Post
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)
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Old 29th Jun 2020, 15:42
  #46 (permalink)  
 
Join Date: Sep 2003
Location: Redding CA, or on a fire somewhere
Posts: 1,782
Originally Posted by Thud_and_Blunder View Post
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.
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Old 29th Jun 2020, 16:14
  #47 (permalink)  
 
Join Date: Jun 2020
Location: south of Germany
Posts: 0
I would like to thank for this nice discussion.

Very nice Chinook background and hilarious content

Last edited by Senior Pilot; 29th Jun 2020 at 21:06. Reason: Complaint about moderation by a newbie removed
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