bravo turbo clamps

[toomany]

i know this had been discussed ad nauseam before but i couldnt seem to locate prior posts. regarding the bravo turbo clamps - do both the welded and riveted need to be replaced after 2 torques or is one able to be used past the 2 torque limit? i need to replace the tailpiece section of the exhaust due to heat erosion at the tailpipe bend but want to make sure about the v-clamps before i venture into it. last price i got was 2k per, which is ludicrous in my opinion. i got the entire exhaust section from plane exhaust in fl for $1200 - they did a fantastic job on the bends and welds, we'll see how it mates up.

 

 

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[Rick Junkin]

@toomany Only the riveted v-band is approved for installation, P/N NH1009399-10 (Aeroquip) or 40D23255-340M (Textron-Lycoming).

Here's the SB from 2004 that established the requirement.

SB 283a - exhaust v-band and deflection shield.pdf

And here's the Lycoming Service Instruction that explains how the v-bands are to be installed.

Assembly and Torque Procedures for V-Band Couplings.pdf

[LANCECASPER]

8 hours ago, toomany said:

 

i know this had been discussed ad nauseam before but i couldnt seem to locate prior posts. regarding the bravo turbo clamps - do both the welded and riveted need to be replaced after 2 torques or is one able to be used past the 2 torque limit? i need to replace the tailpiece section of the exhaust due to heat erosion at the tailpipe bend but want to make sure about the v-clamps before i venture into it. last price i got was 2k per, which is ludicrous in my opinion. i got the entire exhaust section from plane exhaust in fl for $1200 - they did a fantastic job on the bends and welds, we'll see how it mates up.

 

Yes, the riveted clamps still need to be replaced after two retorques, and as @Rick Junkin mentioned, that's the only clamp allowed since 2004.

[toomany]

thanks Lance - greatly appreciated

[toomany]

Thank you very much Rick. 

[Dammit Bill]

Yes, the riveted clamps still need to be replaced after two retorques, and as [mention=15047]Rick Junkin[/mention] mentioned, that's the only clamp allowed since 2004.

3 torques total. I personally find this ridiculous. I believe it only calls for 60 lb-in and it gets safety wired too


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[LANCECASPER]

7 hours ago, Dammit Bill said:

3 torques total. I personally find this ridiculous. I believe it only calls for 60 lb-in and it gets safety wired too
 

The downside though is that when it does come apart, the exhaust becomes a blow torch and makes it through the heat shield and the firewall in a very short time and kills all of the occupants.

In the late 90's/early 2000's when there were some catastrophes in the M20M with the spot-welded clamps and we lost people we knew, it was sobering to those of us who owned Bravos. It drove home the point of how critical this one point of failure can be.  Since the new clamp was introduced with the Service Bulletin and the limitation on retorques I don't know of a fatality that has resulted - that tells me they got it right. I hope it stays that way.

[jetdriven]

Mooney did change the design of later bravo airplanes, and I think earlier ones were modified, they put a heat shield between the turbo and the firewall, and they rerouted the brake line tubing away from the area directly behind the firewall. That famous crash was because the outlet of the turbo torched a hole in the firewall, and then melted some plastic tubing that had brake fluid That would empty from the reservoir and feed the fire. Pretty much worst case. 

[Dammit Bill]

The downside though is that when it does come apart, the exhaust becomes a blow torch and makes it through the heat shield and the firewall in a very short time and kills all of the occupants.
In the late 90's/early 2000's when there were some catastrophes in the M20M with the spot-welded clamps and we lost people we knew, it was sobering to those of us who owned Bravos. It drove home the point of how critical this one point of failure can be.  Since the new clamp was introduced with the Service Bulletin and the limitation on retorques I don't know of a fatality that has resulted - that tells me they got it right. I hope it stays that way.

Totally understand.

However, when the FAA makes it unreasonable for companies to produce/certify parts and the only vendor stops production, a $60 clamp that was selling for $400 suddenly becomes impossible to source and costs $1,700 if you order one and wait 10 months to receive it


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[Dammit Bill]

Sorry

Pocket posting

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[LANCECASPER]

13 minutes ago, Dammit Bill said:

Llll zzzzzzzzzzlzzz. A a zgm

P
 

That's easy for you to say . . . lol