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-   -   Bell 407 (https://www.pprune.org/rotorheads/182751-bell-407-a.html)

sprocket 8th May 2004 20:15

A slightly longer TRGB output shaft usually fixes the problem of contacting the tailboom. Isn't that how they cured the AS350 problem in the early days?
Might mean a complete re-design of the gearbox, aahhh, what the heck lets just try the cheaper band-aid fix instead!

Still some un-answered questions in this incident though, like how can the T/R contact the boom without closing the gaps (as DNR) has written?
Is there an assembly issue? ie was the spacer on the output shaft in its correct place?

Lu Zuckerman 8th May 2004 20:46

The truth according to Bell
 
To: clipboard


This is the first time ever that Bell is now in a position to evaluate the situation, as everything on the helicopter is intact. During the 407 crashes, the helicopters were normally totally destyroyed, so Bell could not say what caused it. Here is the evidence. The "quick fix" that Bell promised, has failed, and all 407's should therefore regarded as suspect.
In Iran we had a pilot that was demonstrating engine failure on an AB-205 and entry into autorotation and his student didn’t respond in a timely manner. As a result the rotor speed decayed and the pilot lowered his collective and entered into a mild dive. During this time he attempted to reengage the engine but the engine needle oversped the rotor needle. He attempted restart two more times with the same result.

He entered into a successful autorotation and made a run on landing on soft earth. While the rotor was running down he was filling out his paperwork when the rotor came off the mast and in the process it hit the pylon and as it spun around the stabilizer bar punched into the helicopter just behind the pilot. This was the first Bell helicopter to have experienced a mast separation and survived. It could serve as a prime subject into the mast separation phenomenon.

In the investigation it was determined that the free wheeling unit was severely damaged most likely due to compressor stall. The maintenance records did not show any indication of this helicopter experiencing a compressor stall. Bell said that the rotor hit the pylon because the pilot used aft cyclic during the landing. To do this the structure would have to yield to allow the transmission to lean back far enough to allow the rotor to hit the pylon. There was no deformation. Bell brought in a metallurgist who said that the fracture was due to instantaneous stress caused by the blade hitting the pylon. I tried to fight this conclusion but I was overruled. We sent the mast and the stub to Agusta for testing but never got a response.

About a week later the Bell rep came up to me and asked me if I knew that the free wheeling unit as well as the entire drive line had been subjected to not just one but three compressor stalls. He knew we were investigating the incident but he never came forward nor, did he initiate any structural and dynamic checks on the helicopter as required by the maintenance manual.

Another point I came across was that our AB-206s were maintained as commercial aircraft. When the time change items were to be replaced they were then maintained as OH-58s which had higher time limits on the parts.

I brought this along with many other problems to the attention of Bell but Bell never did anything about it.

So much for corporate ethics.

:E :E

Head Turner 10th May 2004 10:04

Corporations are just the same as governments. They lie.

Where are the weapons of mass destruction - the reason for the Iraq war. Now there's a cover up going on in regard to the POWs.

Bell will mislead. But positively, they will sort the problem bit by bit and then claim that they have spent millions and have advanced technology for the benefit of their helicopter business.

I'm cynical because Corporation like Governments tell us any old thing if they believe we will be stupid enough to believe it.

francois marais 10th May 2004 14:51

Hiya Lu, I enjoyed your story.

I know the said helicopter, the company, the pilots that work there, and the pilot involved in this particular incident. They're all good guys, very professional, and there is no way that the pilot involved here, will bullsh1t his way thru this one.

Bell are not being honest here. Simple! There is a major problem with their 407, and they don't wanna know. There is NO reason whatsoever, not in normal conditions or in gusty conditions, for the tail rotor to connect with the boom during flight or shut down. Irrespective of what Bell are saying, and/or what they are publishing in the manual.

When the first 407 incident occurred, Bell were quick to issue AD's and IL's and implimented a number of "limitations". Vne limitations, Vop limitations, pedal limitations..... et al. Some pilots, with thousands of hours of experience, came to the conclusion that the 407 was a stretched version of the Long Ranger, with 4 blades and a heap more power. No major design changes to the fuselage, and expressed no surprise when something went wrong the first time.

Bell is quick to blame the pilot, but I can assure you, you may think that we are all stupid Mr. Bell & Co, we are not. We view your helicopter with sceptism and wonder what fabrication you will come up, next time someone dies in a 407. Pilot error no doubt!:mad:

spinningwings 11th May 2004 14:55

Jeeez Guys! ....take it easy ...any reading would think there might be a PRODUCT LIABILITY PROBLEM here!!!!!!!!

;) ;) ;) ;) ;)

407 Driver 12th May 2004 05:47

Question...How many 407's operate in South Africa?

(Canada has 26, the USA has 329)

bladestrap 12th May 2004 07:58

Product liability???? Maybe!

Rumour has it that Bell is now gonna give the owner a brand new beefed up tail boom. Are they doin this as a favor to keep the owner happy, or are they doin it becoz they know that would be the right thing to do?

Helipolarbear 12th May 2004 09:02

Will it take another incident, possibly with someone famous on board who becomes a fatality. Followed by a massive litigation suit......and then Bell will decide to cut their losses....litrally..and pay and fix!!!
If you are a 407 Helipilot, and you think everything is kosher, go ahead and keep pullin pitch.......it's your own risk!
The SA incident sounds serious enough that if Bell were serious about their product they would at least do a detailed inspection and follow up....if only to save their own bacon!;)

As ever Lu, enjoyed your Persian Tale!!!!:p :}

God Bless Sikorsky and every other manufacturer that listens to it's pilots and takes action!!!!!:ok:

407 Driver 12th May 2004 16:02

If you are a 407 Helipilot, and you think everything is kosher, go ahead and keep pullin pitch.......it's your own risk!

I think that goes for every type, not just 407's. Are the 10 crew/pass on the ERA 76 last month "less-dead" than if they were on a faulty 407? Or how about the crew/passengers on that Bristow 76 that threw a blade in the North sea 2 years ago?

You offer Good advice, but I'd caution everyone to be ultra careful, question everything, accept no faults, maintain limits, give yourself the "out".

I don't fly a 407 knowing everthing is Kosher( whatever that is?, I've only seen that word on Pickle Jars? Must mean "filled with Garlic?) nor do I fly an L3 or a 212 or ? knowing that everything is always OK.

spinningwings 12th May 2004 19:26

By way of asking questions about the 407 ....has there yet been any indication of what caused the Queensland ( the CHC rescue machine) 407 to fall out of the sky ....will that prove to be another "pilot error"???


:confused: :confused:

407 Driver 12th May 2004 20:05

Do you mean this one...night VFR offshore? http://www.atsb.gov.au/aviation/occu...ail.cfm?ID=547

Dynamic Component 12th May 2004 23:18

spinningwings,

did you expect to see anything BUT pilot error on the Qld 407:confused:

You should know by now that if the problem can't be found it becomes the pilots fault:mad: :mad:

Don't get me wrong-I do think the 407 is a good aircraft(altough I've lost a friend in one:( ), it's just a pitty about the TR problems.

:} :}

misunderstood 12th May 2004 23:42

I thought it was pretty clear that the Queensland night accident was a classic case of spatial disorientation .... ?

407 Driver 13th May 2004 00:45

Given the multiple and rapid changes in heading and altitude prior to loss of radar coverage, one may suspect that.
The Official word is....the investigation is still "Active"

Shawn Coyle 13th May 2004 13:58

Given the high visibility of the 407 tail rotor problems, you can rest assured that Transport Canada, who is the certifying authority, is watching things pretty closely, even if you are of the opinion that Bell Helicopter isn't also pretty damned concerned if they see a problem.

Most of us have been around enough to realize there isn't a perfect:
a) design
b) manufacturer (engine, airframe, component)
c) operator
d) maintenance facility
e) airworthiness certification authority
f) pilot
g) operational authority
h) training school

If there were a perfect one of any of the above, don't you think it would corner the market in that category?

The question is
What do we do until the perfect thing comes along?

belly tank 20th July 2004 01:16

Bell 407 Demonstrates High Altitude Performance
 
I may as well post this whilst i was browsing at the Bell site, for you 407 fans!!

http://www.bellhelicopter.com/en/com...7_in_Nepal.jpg

Adding to its already impressive list of accomplishments on July 1 2004, Bell 407 flown by Bell Senior Experimental Test Pilot, Eric Emblin, and Flight Test Engineer, Ed Lambert, the aircraft landed on Tillcho Peak in the Mustang area of northern Nepal Himalayan mountain range at an altitude of 22,180 feet Hp (24,971 feet Hd). This remarkable flight completed a weeks worth of demonstrations and testing, which included low speed controllability flights, IGE/OGE hover checks, and general performance evaluations at altitudes in excess of 18,500 feet.

The Bell trial team based its operation out of the Jomsom airport (elevation 8,800 feet) and performed most of their test sorties in and around Mustang District area. This testing was conducted to verify performance capability outside the current published 407 flight envelope and was necessary to pursue key international military programs.

With over 600 Bell 407’s operating in more than 50 countries, these trials represented the first appearance of the 407 in Nepal. While the 407 has already developed a solid reputation as an excellent high altitude performer, flying in the Himalayas offered an opportunity to take the 407 to an unparalleled level.

Bell’s six-member flight test team was lead by Steven Woolston, Director of Asia Pacific Programs, and Dale Cato, Program Manager for Light Helicopters. Mr. Emblin, who conducted all of the high altitude flights, stated “We pushed the helicopter to the edge of its operational capabilities and it delivered as predicted. The 407 demonstrated plenty of margin everywhere.” Additional team members included Steve Bornais, Experimental Flight Mechanic and Chris Ankrom, Rolls Royce Director of Technical Support. As a further endorsement to the 407’s durability, the only maintenance performed during the test program was daily preflight inspections and topping off fuel based on mission requirements.

Ok back to work now!!

cheers BT

NickLappos 20th July 2004 01:27

A most impressive achievement! Congratulations to the crew!

Anyone know the highest helicopter landing yet recorded?

SASless 20th July 2004 01:46

Nick dear boy....landings are a given....it is takeoffs we wish to hear about....the Bell Press Release seems a bit vague on that.

I copied the pertinent bit from the PR ....

".....the aircraft landed on Tillcho Peak in the Mustang area of northern Nepal Himalayan mountain range at an altitude of 22,180 feet Hp (24,971 feet Hd). "

The question does arise....did the aircraft?

More importantly...being here at the base of some fairly high peaks and some other small lumps in the earth's crust....what kind of payload, etc....did they tote around with them. I want something to work around 15,000 feet and do so with some generous OGE capability. Bell has never been able to produce anything that did that very well and have a tail rotor that could do more than make a lot of noise.

Being a bit cynical here....but I can be convinced if Bell can show me the numbers.:E

The Sultan 20th July 2004 13:21

It is not still there.

The Sultan

helmet fire 21st July 2004 02:16

Now there is a market opening up: take a tourist 407 and land on Everest...they will be queued up for miles - passengers reuired to travel one at a time!:ok:


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