Cameron Service Bulletin SB20 issued – Brass-backed Rego Couplings
The mystery is over. Cameron Service Bulletin SB20-0 has found a use and is now out of the ‘not issued’ category. Classed as ‘Highly Recommended’ and it references Rego 7141F hose connectors. That is the threaded type fitting on the end of liquid hoses that screws onto the cylinder. It is dated May 2014 so has been hovering for sometime.
According to Camerons ‘Historically hot air balloon burners were fitted with Rego 7141F connectors originally designed for use with fork lift trucks. These connectors are manufactured with a brass centre body and brass connecting nut (back-nut). These fittings are manufactured to industrial standards and were fitted to burners by many balloon manufacturers. Later versions, designed specifically for Hot Air Balloons, are manufactured with stainless steel centre bodies and connecting nuts. Testing has shown that the brass versions fail under abuse loads at approximately 50% of the strength of stainless steel components.’
Compliance involves deciding what type of material the fitting is made of. Normally this is straightforward as brass is a yellowish going dark gold with ageing. Some fittings are plated brass so you will need to file a corner of one of nut flanges to see what is underneath. Camerons Highly Recommend that any brass couplings be replaced with a Stainless steel version part number CH-0144-0001. The maximum torque settings for fitting the hoses is 20nm for ¼ NPT (tapered thread) and 15nm if a 3/8 BSP (parellel thread) is used. Full details concerning fitting procedures and torque settings are in the Cameron Maintenance Manual Issue 10 Amendment 3 section 4.2.6.
This Service Bulletin follows on from investigations following the Egyptian accident. From our perspective, historically brass backed fittings have not been fitted by us as replacements for failed couplings for years. In the UK failure of brass backed fittings have only been a result of over-tightening when being fitted to new hoses or cracks being found when operated in extremely cold climates. We have only ever come across a few instances and these have been detected during the pre-flight test or by the owner having fitted a new hose and discovering that, despite applying eleventeen wraps of PTFE tape, it still leaked! As this is Highly Recommended and NOT Mandatory then our advice would be to check your coupling and if it isn’t leaking or shows any sign of damage (including any mullering to the back nut) then treated with care it should be fine. The replacement Cameron Stainless fitting is about £61 plus the deadly, p&p plus a Form 1 (£8.00) bringing it to around £90 and then the fitting, or if you-do-it yourself then it will need to be signed off by an approved inspector.
Other manufacturers do use brass-backed Rego fittings predominately Kubicek who use a ¼ NPT thread and Ultramagic that use a 3/8 BSP thread. Lindstrand use a 3/8 BSP stainless backed fitting. The 3/8 BSP thread is a lot less likely to fail as overtightening will not necessarily crack the nut. Don’t forget that fittings on manifolds may also have brass backed Regos. This SB is not only officially directed at Cameron burners (or manifolds) but applies to all burners regardless of the manufacturer that are used with Cameron balloons and also draws attention to the use of brass backed fittings as used by other manufacturers meaning that other manufacturers may issue a similar Service Bulletin.
Service Bulletin 20 is now on the Cameron Balloons Limited Website. Scroll down under Support or go to the page at http://www.cameronballoons.co.uk/uploads/Approved%20Modifications/Support%20Files/Service%20Bulletins%20-%20All%20Types/SB20_0_May14.pdf