Brown trouser moment.......

[FD2]

Yes - we had a few blade tape detachments in the Wessex.

An amusing case happened much later on the S76 at Norwich. Bits of blade tape were stuck over particularly badly abraded parts of the leading edge to delay a particular blade being changed until it could be sent off for a proper repair at a planned maintenance time. Tracking and balancing a replacement blade could be a long process best done at the weekend. If a piece of tape became partially detached near the blade tip it could make a very loud whistling noise - as Ops said when we landed one day you didn't need to call on the radio with your ETA we could hear you coming for ages. Inside there wasn't much extra noise or increase in vibration above the usual clatter.

The noise and vibration would have been nothing like as bad as that Firehawk though - that looks like a real brown trouser job.

[TheGreenGoblin]

Yes is the answer to your first question above. It was absoutely required to tie the blades down when the helicopter was unattended. On the Bell 47 - and any other two bladed type with a teetering head main rotor - if you didn't tie them down and the wind was gusty then the blades would flap up and down. This could then cause "mast bumping", that is the head assembly could hit the main rotor mast. That can also happen in flight in a teetering head helicopter if you put in cyclic inputs having allowed a negative or low g situation to arise. There have been many accidents like that where, with negative or low g, the teetering head has struck the mast in flight and the mast fractured allowing the main rotor blades to depart from the helicopter - Bell 47, Bell 206 and Robinson R22 and R44 helicopters often feature in accident reports when this occurs.

EDIT: Here is an accident report on the R22,G-CHZN, fatal accident in 2012 which was due to mast bumping: AAIB Bulletin 2/2013

Was doing some reading on the mast bumping phenomenon and note another type, that I had hitherto been unaware of, that utilised a teetering rotor. Namely the Fairchild Hiller FH 1100.

https://en.wikipedia.org/wiki/Fairchild_Hiller_FH-1100

images.jpeg (5.18 KiB) Viewed 236 times

http://www.kathrynsreport.com/2017/05/f ... g.html?m=1

[CharlieOneSix]

The sales of the Hiller FH-1100 in the UK were dealt a severe blow when one fatally crashed whilst demonstrating at the Paris Air Show in 1969. Sales never recovered and the JetRanger at that time became the helicopter of choice. The pilot was one of my RN instructors, Terry MacDonald. There is a grainy video if you want to look for it. There are those that say he mishandled the helicopter whilst zooming into a wingover or torque turn but if you watch the video carefully there is a small abrupt movement in cyclic and others including me think there was a control fracture or malfunction. That video contradicts the ex-RN helicopter pilot's statement in the ASN report which says he went into cloud and reappeared upside down. ASN Report Hiller FH-1100 G-AVTG

[TheGreenGoblin]

ASN Report Hiller FH-1100 G-AVTG

"The Hiller was flown by one of my RN instructors, Terry McDonald. Terry started as a RAF fixed wing pilot, moved on to fly a VC 10 for the Nigerian president at a time when they were being removed rather frequently. Terry used to joke " Whose the president today?"."

Clearly a realist. I doubt that a man with such clarity of thought would have made a silly mistake. RIP.