Balloon Repair Station

Guide to Inspecting Flight Cylinders

Inspecting Flight Cylinders Last update 12.12.2014

This guide is designed to assist with the general inspection of cylinders and highlights a number of areas where special care and attention needs to be taken. In all cases the manufacturers’ latest Maintenance Manual and Inspection Schedule must be used when inspecting cylinders and must be adhered to. Airworthiness Directives and Manufacturers’ Service Bulletins must be checked prior to inspection and the cylinders checked to ensure compliance. All propane cylinders are constructed in basically the same way and all require the same degree of care when handling and inspecting them.

Most inspectors have a well-established methodical approach to inspecting cylinders and at what point during the inspection the cylinders get inspected. The order presented here may suit some and not others. As long as all the points are covered it does not really matter but if you have, or are developing, a system then stick with it if it works for you.

There is conflict with road transportation requirements for thin-walled pressure vessels some of which have been incorporated by the manufacturers into their manuals, or addressed by the way the cylinder is manufactured, however the airworthiness of cylinders must not be confused with the road transportation requirements. In all cases the appropriate Manufacturers’ Maintenance and Flight Manuals take preference over any road transportation requirement.

Golden Rule
If you are asked to inspect a cylinder, or you inspect a cylinder as part of an annual or periodic inspection, then do just that. Unless the cylinder is found not to be airworthy for structural or damage reasons, then carry out a full inspection even if it is due for a proof pressure test or PRV change. Not inspecting it fully can mean extra cost for the owner.

If you have any doubts or concerns with the cylinder’s integrity then refer it to the appropriate manufacturer.

Bit of basic scientific stuff
As the first part of the inspection proper covers the structural integrity of the cylinder herewith follows a bit of stuff on the materials and construction of the cylinders used.

(i) Types of stainless steel
There are many different types of stainless steel all having varying properties. Within the types there are many different grades, some for specific applications. Despite the claims, stainless steel can, and does, corrode. These days the reasons behind the various types of corrosion in stainless steel are far better understood. In the main it occurs at a molecular level and is very dependant on the grade of the stainless steel, environment and the way the item is manufactured and used. All the older stainless steel cylinders we use are made from various grades of austenitic stainless steel. More recently duplex stainless steel has been used.

(ii) Austenitic Stainless Steels
Austenitic stainless steel contains nickel and chromium. Around 18% chromium and 8% nickel, although the actual composition varies depending on the type. They are non-magnetic and cannot be hardened by heat treatment, although they strain harden rapidly when cold worked. Almost all stainless steels are ductile and therefore can be formed, but the Austenitic types are pretty much the best in this respect. They are also amongst the most highly corrosion-resistant of the stainless steels.

(iii) Duplex Stainless Steels
Duplex stainless steel combines the optimum properties of austenitic and ferritic types. They contain 18 – 26% chromium plus 4.5 to 6.5% nickel and have good resistance to stress corrosion cracking. In times of high alloy prices the cost of duplex stainless steel is much less than austenitic.

(iv) Austenitic Stainless Steel Cylinders
There are a number of types of corrosion that austenitic stainless steel is prone to but the most common, as far as we are concerned, are pitting, crevice corrosion, intergranular corrosion and stress cracking corrosion. Pitting and crevice corrosion are very similar, the former being more serious than the latter. Both can be very localised and can sometimes progress relatively rapidly. Both are not helped by salt water or salt water atmospheres. Intergranular corrosion can also be very localised and is often a result of the welding process. Very basically, crevice corrosion and stress corrosion can both be induced during welding through incomplete weld penetration or poor cleaning after welding. Stress corrosion is, as the name implies, brought on by stresses incurred both during manufacture and service life.

Whereas it is unusual that the main sheet-formed body itself will corrode, the welded seams and fittings pose a very different scenario. Stress in cylinders is largely induced during manufacture but, during service life, heat changes, pressure changes and repeated impacting either through arrivals back on terra firma, being knocked about during transport or dumped unceremoniously in and out of the basket for refuelling will increase and accentuate the problem. In the case of earlier stainless steel cylinders welding was generally carried out by hand so the evenness, however good the welder was, varies throughout the run. Starting and stopping the weld also causes variations. Unless great care is taken contamination of the weld can occur. That, combined with the molecular changes during the welding process, will all help to precipitate the onset of corrosion. Despite undergoing vigorous testing throughout the manufacturing stage and a pressure test before release, it doesn’t take much to realise that any cycling will affect the area where the most variation in the weld quality and molecular structure occurs. It follows that those will be the areas where corrosion is most likely to occur and the areas most likely to fail first.

Later machine-welded austenitic cylinders are far less likely to suffer from corrosion in the welds as the process is far more even and the environment in which they are welded is better monitored and controlled.

(v) Duplex Stainless Steel Cylinders
The later cylinders are made from Duplex Stainless Steel, basically a mix of grains of austenitic and ferritic stainless steels formed during the cooling process. It is about twice a strong as austenitic steel and less prone to stress corrosion and doesn’t suffer from intergranular corrosion. It is far less ductile (e.g. looses more strength if dented) than austenitic. Its composition is such that its resistance to both pitting and crevice pitting is about the same as austenitic stainless steel so the possibility for corrosion and leaks in Duplex cylinders, especially in the seam areas, is about the same as for Austenitic.

(vi) Aluminium Cylinders
The aluminium Worthington cylinders that are widely used in ballooning are defined as thick walled vessels. From a structural integrity type of thing they are extremely resistant to mishandling, however the downside is that, by the very nature of aluminium, they are very prone to damage and it takes very little effort to wear or remove lumps of aluminium.

Aluminium absorbs dents far better than steel and is less likely to rupture on impact. In the majority of environments we use the cylinders in, the only corrosion likely to take place is a very light surface oxide coating that is easily brushed off. Very occasionally external and internal pitting can occur.

It was widely thought that internal pitting caused by contaminants in propane or water lying in the bottom of the cylinder would be a problem but this has rarely been found. The biggest problem has been thread corrosion from the use of steel (even plated or galvanised) set screws being used to secure the contents gauge and thread wear as a result of over-tightening valves into the tapered threads used in the bosses. Early Thunder Worthington cylinders used a gloop on the threads that doubled as a type of Loctite. Removal of valves and fittings can be almost impossible in some cases and often results in the threads themselves being damaged. Under no circumstances should tapered threads in aluminium flight cylinders be re-cut. Even says so in the Manual!

Aluminium remains extremely stable during the welding process and, across the gas industry, leaks through welded joints and seams are extremely rare.

Love your Worthington.

(vii) Titanium cylinders
Titanium takes many forms but the stuff balloon cylinders are made from is basically an alloy containing aluminium and vanadium. Although very stable, very strong and extremely corrosion resistant, it is easily contaminated during the welding process (it will actually burn in air at high temperatures). Welded titanium components, including cylinders, will often require stress relieving to prevent stress corrosion, usually by annealing. There was a recall on early Cameron Titanium cylinders for this very reason. Affected cylinders should have an ‘S’ engraved after the part number. The Airworthiness Directive and Service Bulletins referring to these is now closed.

Carbon steel and titanium do not get on and the biggest cause of corrosion (galvanitic) in titanium is through imbedded or smeared ferric particles. Titanium is extremely difficult to clean so its best not to bother. Under no circumstances should wire wool or carbon steel brushes be used to remove grime or dirt.

Nifty tip: It is good policy to carry a magnifying glass, at least x10, to check suspect areas for all types of corrosion. Hairline cracks can be extremely difficult to spot and may not be right through a weld or fitting so no leaks may even be detectable. Folding Printers’ or dress makers’ magnifying glasses combined with a bright light are pretty good. Lightly moving your fingernail across a suspect crack can also be a good initial indicator.

What you will need
Gloves, torch, tape measure, Blue Tack or depth gauge, pliers, a decent flat and cross-head screwdriver, Allen Keys (UNF and metric), popper for valves. Open vapour and liquid fittings, Padded mat. Good quality leak detector, Indelible marker pen, small mirror, Magnifying glass minimum x10, cloth for wiping down.

First – The Paperwork
Just like all the other aspects of inspecting you need to record the details. Is the cylinder compatible with the basket and balloon? Are the cylinders listed in the logbook the same as the ones that you are about to inspect. Have their weights been recorded in the front of the logbook?

Nifty tip Don’t copy the serial numbers out of the logbook or off of a Pressure Test or PRV change sticker, copy it off the cylinder then check against the paperwork. Dyslemexia in renumeration has been known!

Record the cylinder details prior to the inspection proper starting. You need to record the cylinder manufacturer, type or part number, serial number, date of manufacture. The date of the last Proof Pressure Test (if applicable), Internal Inspection (if applicable) and the date of the PRV (if applicable). It is seldom the case that the PRV date is the same as either the construction date of the cylinder or the date of the proof pressure test. There may be times when a cylinder may be presented as ‘stand alone’ or is to be added to the balloon having been recently purchased. There may well be no history in these cases and you may have to create (not to be confused with ‘be creative with’) the paperwork that goes with it. This is also the time to check if there are any SBs or ADs applicable to the cylinder.

If a cylinder has no history with it and is neither engraved nor carries a recognised PPT sticker then you must assume no PPT has been carried out on it however PPT testing facilities keep records of all the tests they carry out so it will be worth checking with them to see if it has been done.

For the purpose of this guide let us assume the cylinder has propane in it and is at a pressure of around 80psi. That means that it is well within its operating range, an important consideration if you are going to test it. If you are presented with an empty purged cylinder, or an empty cylinder with no history, then pressurise it to 100psi.

Testing a cylinder with a pressure below the minimum operating pressure of the burner it is to go with will not be practical.

Inspection of the cylinder body
This then is the ‘get-out-of-doing-it’ bit and aimed to save you time and effort trying to get that shrunken old Thunder cylinder jacket off of an ancient Worthington if you don’t have to! It may be too late as the industrious owner may well have stripped the hapless cylinder to its bare bones already. Never mind. It may seem obvious, but if the cylinder body itself is not fit for use then there is little or no point in carrying on with the inspection!

Fortunately catastrophic failure of a cylinder in normal operation is extremely unlikely as indications of developing corrosion or serious damage can be spotted at an early stage and the cylinder withdrawn from use long before such a situation could occur. Bearing this in mind there should be no hesitation in failing, or seeking the manufacturer’s advice, any cylinder if you suspect corrosion. Blackening in the welds, rust blooms on the surface or any evidence of localised discolouration or pitting are all good indicators of developing corrosion. By using a good proprietory brand of leak detector and being consciencious in its application then, combined with other damage criteria, any problems can be identified at a very early stage. If there is any doubt in your mind then refer the cylinder to the manufacturer and make a note of your action.

If you find any acceptable damage make a note of it and circle, or mark, the area with the date and your inspector number. Any cylinder that has been involved in a fire must be rejected. Note your finds on the Inspection Sheet and later in the logbook. If possible try and find out what has caused the damage or how the damage was caused.

Before starting the inspection ensure all the valves are closed, this will avoid confusion in locating leaks during the first part of the leak test. Invert the cylinder to have a look at the base and the lower guard ring. It is preferable to do this on a suitable padded mat. In the case of cylinders fitted with top guard rings mounted on tubes take care you don’t drop them onto the top ring, especially if they are full, as you may induce a failure by impacting the support tubes into the top dome!

If there is a build up of soil, or more unpleasant stuff, on the base clean it off, paying particular attention to the joint between the cylinder base and lower guard ring. The easiest way to remove this is by compressed air or a small stiff brush or stick. Do not use a steel wire brush. Occasionally, caring pilots will glue hard foam to the base in an attempt to afford some protection. Unfortunate as this may be, it must be removed along with any residual foam. You must be able see all the base. Check the base for damage or signs of corrosion paying particular attention to the welds and guard ring noting anything found. Guard rings, especially the base ring must protect the dome. A straight edge placed across the guard ring should remain clear of the bottom dome.

Nifty tip A useful way of checking the size and scale of any damage is to press Blue Tack, or plastercine into the dent and thus get a true 3D image. A commercial tyre-tread depth gauge is another useful tool. If a tape measure is required then it probably outside the limitations.

Finally, spray leak detector around the guard ring where it joins the cylinder base, both inside and out. Leave for a few moments then check for leaks paying particular attention to the welded areas.

The most common failure points are:

  • Damage to the base of the cylinder. Mainly caused by protruding basket runner bolts or the cylinder being impacted on large stones when being turfed out of the basket. You will need to refer to the appropriate Manufacturers’ Rejection Limits, found in their Maintenance Manual to ascertain the true scale of the disaster.
  • Damage to the guard ring. Generally, if the guard ring has been distorted or crushed such that it no longer protects the cylinder base then it has failed.
  • The owners name, address and postcode is engraved on the cylinder itself. Muppetry. This will usually be considered as a cut or groove defined as ‘a sharp impression where metal has been removed or redistributed. Its fate will be dependant on whether the thickness of the cylinder is known. Don’t confuse this with manufacturing marks where numbers and letters are etched onto the metal. These often turn up on the Cameron Duplex cylinders and occasionally Ultramagic.

If this bit turns out to be all hunky-dorey then its time to get mucky and strip the darling. Turn the cylinder upright and remove the jacket.

Nifty tip Worthington cylinders only require one string to be untied to get the jacket of. When undoing the drawstrings take care that the drawstring doesn’t disappear into the cover as you pull the cover open! It usually does it on the last one you look at. Better still give the cover removal and refitting job to the owner! Bishy and Ultramagic jackets use elastic. Lovely.

Have a good look at the top dome of the cylinder and ensure the joint between the top ring is clear of broken pencils, decomposing extra strong mints, bits of oak tree and general detritus. Make sure any glue, tape or stickers that may conceal damage to the main body are removed or cleaned off. Heater tapes must be removed. Heater tape wires shorting-out under the securing tape often results in serious pitting. In the case of PPT stickers they can stay providing there is no evidence of scoring or damage that may have passed through them to the cylinder wall.

Check the body and all the seams for damage and any signs of corrosion. Running your hands over the body of the cylinder will often reveal dents, distortion or damage that may not be easy to see. Take care when doing this on aluminium cylinders where gouges and scratches can result in the displacement of material and sharp protrusions just waiting to get you.

Check all the bosses for damage or distortion paying particular attention to the welds. The process of welding will cause some distortion to the cylinder, however if fittings are clearly sitting at an angle to the vertical or horizontal plane then the boss has probably been subjected to a hefty knock or leverage. With guard rings that are mounted on posts (T&C, Lindstrand, Sky) check that these haven’t been impacted into the cylinder dome. Check for cracking or corrosion on the welds surrounding bosses and fittings.

If all looks well then carefully spray leak detector over the weld seams, bosses, welded areas and any areas that look suspect. Give the detector time to work. Testing the cylinder body with it lying horizontally, a section at a time, is an good option.

The most common failure points are:

  • Large dents to the cylinder body usually a result of chucking them up onto the side of the basket.
  • Damage caused by not being strapped into the trailer or the basket, or cylinders carried on their side and having other cylinders or burners dumped on top of them.
  • Especially in the case of aluminium and titanium cylinders, abrasion or damage to the top curve and the main body where burners or equipment have been rubbing during transit.
  • Corrosion in or alongside welds and the body, especially in the case of balloons operated or stored close to the coast.
  • Distortion around the bosses. Incorrect practise during the removal or fitting of components can result in distortion to the surrounding areas. Almost always this will impose a twisting or side loading moment to the surrounding material which can have the effect of weakening the material and, in some extreme cases, the weld.
  • In aluminium cylinders, thread failure and gouges, serious corrosion to the gauge screws. Broken gauge screws.
  • In titanium cylinders (Russian type) the original bottom guard ring collapsing or cracking. Lindstrands made a replacement for these.

Valves and bits and bobs
Hopefully the cylinder is still upright. Retrieve the jacket from where the owner lobbed it opr the wind has carried it. Ensure it meets the manufacturers requirements, is not damaged and has the correct thickness of padding. Chuck it in the basket or trailer, that’ll confuse them.

Check where fittings screw into the bosses and where fittings attach to valves. Where new components have been fitted ensure the correct sealants have been used. Hermatite or ‘No Nails’ is not acceptable! Where Dowty seals are used PTFE tape should not be present.

Check the screws or Allen bolts on the gauge are tight and not badly corroded. Crack open the bleed screw and close. The operation should not require undue effort or the use of Molegrips! In the case of some Cameron cylinders ensure the correct type of bleed valve and tube is fitted.

Check that the screws or nuts holding the handles in place are tight. Even with the screws tight there may be some play between the handle and valve stem. Providing it is not excessive and the handle cannot come off this is acceptable.

Pop the dustcap off the PRV and check that there is no corrosion or contamination in the vent tube or PRV itself. If the dustcap is missing it may be an indicator that the PRV has operated or that the PRV has a leak. Check that there is only one PRV present.

If Rego fittings are used check the ‘O rings’, firstly to make sure they are there and secondly check that they are serviceable. There should be no bits missing and the seals should not be hardened (use a finger nail to test if they are still supple).

Carefully open the liquid valve (stand clear when you do this, no peeking down the inside) and vapour valves and operate them throughout their whole range. They should operate freely with no intermittent sticking or graunchiness. Move them back to the midway position. The reason for this is that when leaks through the stem seal develop they can often be stop if the valve is opened fully. Leave the valves open for a few seconds before applying leak detector.

Common failures:

  • Rego ‘O rings’ missing/damaged.
  • PRV dustcaps damaged, loose or missing.
  • Handle screws loose and mullered/incorrect screws/washers fitted.
  • Gauge screws corroded/loose.
  • Orange T&C regulator loose on the stem.
  • Cameron yellow PRV dustcaps missing or broken.
  • PRV vent tube corroded inside.
  • Two PRVs fitted. One stand alone and one built into the vapour valve. The built-in one often turns out to be out of date.

Time to get the leak detector out. Just because it doesn’t produce a bubble bath the minute you spray it on doesn’t mean there isn’t a leak. It takes time to show up smaller leaks so be patient. Don’t forget smell can often be the best form of detection. If you find a leak ensure you can identify exactly where it is coming from.

Nifty tip Do not use a lighted striker to detect leaks. This is bad. There are plenty of extremely good proprietory leak detectors on the market.

Spray leak detector around the base of all the fittings including the welds, fuel gauge and ‘up and under’ the liquid and vapour valve handles ensuring it gets around the stems. If a Worcester ball valve is fitted ensure it is sprayed around the joints on the body and the lever spindle. Don’t forget the vapour regulator and base of the vapour take-off fitting. In the case of the orange T&C type regulator ensure the brass stem into the regulator is tight. The easiest way to do this is to give the take-off a tap with a clenched fist to see if it moves. If it does then it will bubble like mad and thus need tightening.

Operate the valves through their entire range and check again for leaks as you do so. You may have to apply more detector. In the case of gate valves (screw type) a leak is more likely in the midway position of its normal operating range so give the handle a gentle wiggle at this point. With ball valves leaks are more usually from the spindle seal. To check this open the lever fully and exert a slight sideways pressure in both directions on it and check the spindle seal for leaks.

Spray a little down the inside of the PRV, vapour take-off and Rego liquid take-off if fitted. Quick shut-of valves can have either Rego or Tema take-offs. If it is Tema check the male take-off fitting for corrosion or damage and give the Dowty seal at its base and the nipple a spray (nice). The Tema fitting should not leak through the nipple. Gate-type liquid valves always have a Rego-type liquid take-off. In the case of Rego fittings there are two external seals in the liquid take-off part and two internal seals. Leaks can occur between the internal seal for the poppet carrier and the poppet seal itself. The external seals can only be checked when the Rego female hose fitting is attached.

The joint between bosses and fittings on Titanium cylinders, regardless of make, appear to suffer more from the effects of cycling. It is not unusual to find small leaks around the valve/cylinder interfaces (Whoa, again) leaking through the threads.

Bottom line (technical phraseology) is that what you are actually doing is ensuring that there are no leaks between any of the interfaces. Cor!

Be nice time. Some leak detectors have an adverse affect on brass fittings so a good spray over with WD40 or similiar and wipedown afterwards is a good idea. Don’t forget to spray up and under the gate valves and inside the PRV and the Rego and vapour take-offs.

Ensure the valves are all closed and pop the liquid valve. After popping there should be no further venting. Turn the cylinder back over watching (not so far as you fall over) the gauge to ensure it is working. Replace the jacket and, if necessary, retie the draw string. Depending on how helpful the owner/operator was determines which way up you put the pocket! Bring the cylinder back upright retie the top drawstring and put the dead cat, map of southern Italy and the bit of string that most owners seem to keep in the jacket pockets back in. Finally re-pop the liquid take-off. There shouldn’t be any pressure behind the nipple. If there is then the main seal on the gate valve or ball valve seals are leaking.

    Nifty tip It is common practise to stop leaking nipples by spraying copious amounts of WD40 down them then pressurising and popping them a few times. True enough this does sometimes work but it hasn’t cured the problem just postponed the inevitable failure. Don’t do it.

Common failures:

  • Leak through the stem seal on later Cameron vapour valves with the red five pointed handles.
  • Corrosion on Tema take-offs.
  • Nipple valve leaks on Tema and Rego take-offs both liquid and vapour.
  • Leaks through the spindle seal on Worcester ball valves.
  • In the case of titanium cylinders, and Lindstrand cylinders over eight years old, small leaks through the threads of the bosses.

Function Test
Easiest way is to get the owner to put the tanks into the rigged basket (or connect to the burner with it on the ground). What you need to know is that the valves are actually working. You may have ascertained that they don’t leak but now you need to know that they actually work as they should. Make sure the fire extinguisher is to hand.

Check the valves on the cylinder are closed. Ensure all the burner valves are closed. Connect the liquid hose and vapour hose to the cylinder. Open the liquid valve. Check the pressure at the burner (not possible with some burners). Spray some leak detector spray over the connector to ensure the connector/take-off interface (there we go again) isn’t leaking and screws or, in the case of Tema fittings, pushes, on fully. Do the same with the vapour hose. Listen for the sound of gas at the pilot light.

If all is well light the pilot light. Ensure it is running correctly and if an adjuster is fitted to the regulator, ensure it works. Operate the blast valve and ensure the burner runs cleanly and is getting the maximum delivery of fuel. Repeat the process to ensure the hose has refilled. Close the liquid valve and burn off the fuel. Close the vapour valve and ensure the pilot light goes out. This test ensures the vapour and liquid valves are closing properly and not being reliant on the poppet valves in the take-offs.

Off course this part of inspection can be combined with the burner test. If you are inspecting one cylinder alone, and do not have a burner, open fittings can be used but ensure
the area is clear and you are wearing gloves. The usual rules of commonsense should be applied.

So there you are, seven pages and we have managed to inspect a cylinder. Next up, some handy information.

ADs, SBs, PPT, Internal, PRV, lifed components and other useful stuff
In all cases reference must be made to the Manufacturer’s appropriate Flight Manual (FM) and current Maintenance Manual (MM) plus any Supplements, Airworthiness Directives, Service Bulletins or other manufacturer’s issued notices.

Worthington Cylinders
Apart from cylinders marked Worthington there are two other manufacturers that supplied cylinders to early Thunder, Colt and Cameron Balloons namely Lennox and Southampton. All look very similar. As it now very difficult to identify the original balloon manufacturer that supplied them if there is any doubt they can be referred to as DOT4E240. Mini Worthingtons are DOT4E260.

Worthington cylinders that can be positively identified to Cameron Balloons can use the Cameron CB250 part number.

Lindstrand supplied some Worthingtons and will carry a Lindstrand id plate

Cameron Balloons
Applies to all cylinders CBL/T&C/Sky. Refer to current CBL MM Section 6

For Cameron cylinders ID plates are on the top rim.
T&C/Colt/Sky cylinders ID plates are on the bottom guard ring. Some are engraved rather than on separate plates.

PPT information is either on a sticker on the cylinder wall or engraved on the top guard ring (bottom in the case of T&C/Colt/Sky).
PRV details are sometimes on a paper sticker inside the top rim or engraved under the PPT details on the top rim (bottom in the case of T&C/Colt/Sky).

PPT and Internal Inspection required 10 years from date of manufacture.

Cylinder jacket Stainless Steel, Duplex and Titanium cylinders (excluding Worthington DOT4E240 and DOT4E260) Water resistant protective layer at least 25mm thick made from structural cellular foam or similar. CBL FM Issue 10 / CBL MM

Periodic Maintenance CBL MM Supplement 7.52 (includes details on correct bleed valve & tube lengths and affected cylinders).

CBL MM Appendix 3 gives date marking of PRVs

Cylinder fitting torque values at CBL MM 7.52.2

Rejection (damage) criteria CBL MM Section 6.18.5 plus Table 6.1

Check data plate. Older cylinders have a test pressure of 3.3 Mpa. Should be tested and plate amended to 3.0 Mpa.

ADs & SBs
There were three previous cylinder related SBs issued, two recalling early titanium cylinders and one for PRV replacement. These are now closed. Affected titanium cylinders should have a letter ‘S’ engraved after the part number indicating that they have been treated.

There are three current SBs with one being issued as an AD by the CAA.
SB14-0 Colt Propane Cylinders issued June 2006
Relates to inspection of the liquid valve take-off stem weld. Highly Recommended
SB16-0 Cylinder Liquid Valve Self Seal Coupling issued January 2008
Relates to failure of the self seal in Muller hand wheel valves (gate valve) part number CB-0824-0001 dated 12/05 to 08/06. The date of the valve is stamped on the side of the valve body. Highly Recommended
SB17-0 Cylinder Liquid Valve Self Seal Coupling (Hopper) January 2008
Relates to failure of the self seal in Muller hand wheel valves (gate valve) part number CB-0824-0001 dated 12/05 to 08/06. The date of the valve is stamped on the side of the valve body. This relates only to the cylinders when used with a Cloudhopper type balloon. Bear in mind the cylinder may also be used with another manufacturer’s equipment or balloon. Mandatory.
CAA Mandatory G-2008-0002 issued January 2008. Refers to SB17-0

Lindstrand Balloons
Applies to all cylinders. Refer to LBL MM Section

PPT, PRV replacement and internal inspection required 10 years from date of manufacture.
First Internal Inspection 10 years from date of manufacture thereafter every 10 years.
PRV replaced at the same time as the PPT irrespective of date of PRV.

Hydrostatic Structural Inspection LBL MM Section 6.5

In the case of badge engineered Cameron supplied Duplex cylinders. The type, date of manufacture and the serial number is the Cameron one. Later Cameron supplied Duplex cylinders have no Lindstrand id plate.

ADs & SBs
None listed in connection with cylinders.

Applies to all cylinders Section 6 UM MM is the Inspection Schedule
PPT and Internal Inspection required 10 years from date of manufacture then every 5 years thereafter. (D type inspection) UM MM 6.5
PRV valid for 10 years from date of manufacture unless stainless steel type. UM MM 6.6.5

General rejection damage criteria UM MM 6.6.5
Denting of the walls maximum 2mm from original form. Damage to surface maximum depth 0.2mm.

Torque values for fittings UM MM section 4.6

ADs & SBs
SB 1/99 Fisher M220M valve replacement in cylinders. Issued 26/08/99 Mandatory
Replacement of the Fisher connector with a Rego 7141M. Serial number tanks affected:
M-20 from s/n236 to s/n262 with Fisher connection, M-30 from s/n334 to s/n415 with Fisher connection. Fisher M220M connector is similar to REGO 7141M and can be recognised easily as having the inner nipple in black.

Depends on cylinder type fitted see Kubicek MM 3.4.5
Schroeder cylinders
PPT and Internal Inspection required 10 years from date of manufacture. Lifing dependant on where maintenance is carried out. Check with the manufacturer to clarify.

ADs & SBs
Kubicek AB 013a & Schroeder 8025-34 issued 15/01/02
Pressure regulator for pilot flame, brand LORCH, on Schroeder fire balloons VA 50 and VA 70 gas cylinders (manufacturing date up to July 2001) as well as on WORTHINGTON cylinders (manufacturing date up to July 2001). Installation by October 1st 2001.

Head Balloons
Refer to the cylinder manufacturer’s manuals

ADs & SBs
None issued by Head Balloons
Refer to cylinder manufacturer