Are "brew ups" on the increase?

[Guest ozzie]

A weighted object about the size of a small salt shaker, clips into a socket. Then breaks free with a decent bump.

.;)

Not much use on the roads around Cessnock :;)1:

 

 

[bilby54]

Hi Tony,

 

I think that some of the fuel system designs have a lot to be desired and really should not be allowed to fly.

 

I recently grounded a Jabiru because of a strong fuel smell in the cockpit and found a weeping connection at the outlet of the tank. The electric fuel pump is the next device along the fuel path and it is located directly under the fuel tank! The fuel shut off valve is located is located further downstream beside the pilots foot and the fuel filter is last in line before it passes into the engine bay.

 

To make matters worse, the electric fuel pump does not have high pressure cutoff so if the shut off valve is closed, it is quite feasible to blow the fuel line off with very undesirable consequences indeed. The electric fuel pump and wiring are not rated for hazardous area use and leaking fuel or fuel vapour is definitely hazardous!!

 

Disturbing part about this aircraft is that it was first registered GA and passed by a CASA designated inspector. I am not having a go at Jabiru by the way.

 

The only place that fuel and electricity should get together is at the spark plug!!

 

Bilby 54

 

 

[Guest brentc]

Bilby, was the aircraft certified as GA, or a homebuilt experimental GA?

 

 

[bilby54]

Hi Brentc, Homebuilt experimental GA now RAAus. I do not know where the pump is located in the certified A/C but I wouldn't think that it is much different

 

 

[Guest brentc]

Well based on that, it could be hanging on with 1 screw and sticky tape as with GA experimental the aircraft is not inspected as such like in RA-Aus. One of the differences between the two. Persons purchasing a used GA homebuilt should be wary that just because it's GA registered doesn't mean it meets any airworthiness standards.

 

 

[bilby54]

I'm not quite sure what you are on about here brentc as the aircraft is registered RAAus.

 

Tony's original question was along the lines of why so many 'new' aircraft tend to catch fire after a crash, especially a surviveable one.

 

The two points to be considered here are that the aircraft was built to GA standards (aircraft grade single screw and approved tape!) and then transfered to RAAus register with no inspection. The certified model has the same fuel pump and fuel line set up and I would hazard a guess and say that the fuel pump is located under the internal tank.

 

The A/C that I grounded was built to a very high standard and exactly the same cockpit layout as a certified model. It is very feasible for a pilot in an emergency situation to close the fuel valve and have a pressurised fuel line; couple that with a stressfull landing and the fuel line could easily rupture. The survivable becomes a death trap!

 

The fuel shutoff valve should be the first device after leaving the fuel tank; that way, the fuel pump could still be accidentally left on without pressuring up the fuel line. My opinion entirely but maybe someone could advise where the fuel pump is located on a certified Jabiru with internal tank.

 

 

[Guest TOSGcentral]

Hmmm! Interesting Bilby54. That would not happen to be the Jab built by a college (or some such) that RAAus gave a “dispensation†to for use as a trainer – providing it was only to convert GA pilots to ultralights? (never did find anything in the Regs to cover that but ho hum!)

 

It flogged into Watts one day and the pilot was (from recollection) supposed to be doing an instructor renewal with me.

 

It was taxied briskly (in an already wing down condition) at high speed through some of the (then) less attractive features of Watts, banged its tail on the ground (and damn near the prop) and came to a halt with an expectant occupant looking for good things to happen!

 

They did! We celebrated by myself taking the undercarriage to bits sufficiently to demonstrate that it was actually defective (cracked) to underline why the aircraft was standing at a weird angle.

 

I declined to fly it and therefore do the renewal, and went home. The aircraft was gone the next day so I assume it had been flown out! I was powerless to ground it because I had been burned by RAAus when I had the hide to tell them that I had grounded an aircraft and was promptly put in my place that NOBODY but RAAus staff had any such authority!

 

Tony

 

 

[bilby54]

And they reckon women are a strange kettle of fish!!

 

Yes Tony, there were a few stories getting around here about that 'dispensation'. Funny thing is the fella came back beaming that he was a CFI!! Nearly killed one of my old students and scared one so badly that he almost refuses to get back in an aircraft.

 

I am still of the opinion that the fuel system in this model aircraft are potentially dangerous and possibly the same design has been carried over to other breeds.

 

 

[storchy neil]

bilby54 the fuel pump in the storch s is after the cut off taps you are right presure from the pump can blow the hose off neil

 

 

[Yenn]

Sheer madness to have the pump upstream of the tap and I have never seen it. Just think about it, what possible advantage could there be? The tap has to be right next to the tank, so that maintenance can be done.

 

If you fly a plane like that, get it changed.

 

 

[bilby54]

Hi Ian,

 

You are right to say that it is "sheer madness" to have a fuel system set up like that but I am certain that all of the factory built Jabiru ST's and SK's were built this way and they are certified training aircraft.

 

It is probably because it is 'convenient' to install the components in the limited space. I don't think that this setup is limited to Jab's by the way so maybe someone with a 55 registered jab could check that out.

 

B54

 

 

[Guest Nelson Smith]

No the jab.doesn't have a high pressure shut off because the electric pump stalls at about 6lb's / sq in. You don't have to shut the shutoff valve to close the fuel circuit as you describe as the float valve in the carby does it anyway.So what you are saying is that all Jabs. must blow off the fuel hoses at some time!!! COME ON

 

Nelson

 

 

[storchy neil]

nelson please read what we are sayig should you have a bingle as did happen to me i would not want a fuel pump up stream off cut off taps because when you have a bingle 6 lb/sq pumping fuel on to you will get you very wet

 

i have had a fuel pump blow a brand new hows on a chevy motor the boat and motor are in the bottom of the murray river

 

i have had a fuel pump fill a sump of a motor now this pump was suposed to cut out at 7 lbs but malfunction and forced the fuel past the neadle and seat new pump was the only thing i changed it did cut out at 7 lb

 

what was asked was the lift pump before or after the cut off taps on a jab 55 registered

 

i fully agree that the cut off taps be up stream off the lift pump

 

neil

 

 

[rick-p]

Tony I think that you hit the nail on the head earlier with your reference to training or lack of it or even bad practices on the part of PIC.

 

I have seen discussions previously in these forums about fuel cocks that is the pros and cons of leaving them on after shutdown and or turning them off.

 

I believe a lot either have forgotten the importance and the proper use and reason for a fuel tap.

 

The same applies for the use of an electric fuel pump if the engine fitted has a mechanical pump.

 

Some have argued that if you turn off the fuel to a 912 and forget to turn it on at start up you will get of the ground before the engine stops. I don't know if it is true but it really isn't relevant, is it!

 

Some think that you only turn it off so with some carby's you don't lose your fuel on the ground overnight.

 

Fuel taps or cocks or whatever you like to call them are a safety device to reduce the risk of fire in an emergency situation.

 

You are isolating one of the catalyst's for disaster.

 

The same reason why we turn off the electric fuel pump, master switch and anything else electrical or capable of generating heat or a spark on impact.

 

For example a hand held radio if switched on and the battery seperates from it on impact may well explode or spark the same as a digital camera can or GPS.

 

The point I'm making is that if you never touch your fuel tap or give consideration to the other matters I have addressed herein and trained for the emergency how the hell will it all be remembered in an extremely stressful situation that requires immediate attention.

 

I believe that the increased number of post impact fires are due to the fact that the aircraft has impacted the ground in a live state like a grenade with the pin pulled.

 

Scenario, aircraft impacts the ground, master switch on, electric fuel pump on fuel tap on.

 

The impact causes fuel line to break, fuel on hot exhuast and fire starts, fuel is continued to be pumped but if electric pump is out of order then because the fuel tap is on it will in most cases gravity feed fuel to the fire leading to the end result of crispy cooked occupant/s.

 

I can't think of a worse way to meet one's demise.

 

I have often thought about a mecanical operated fire extinguisher system under the hood for ultralights which could be rigged to go off on frontal impact filling the engine compartment with foam or powder.

 

There is a material you can use in the fuel tanks of land vehicles which reduces explosion and burning, the military have used it but from what I understand is that it's not suitable for aircraft fuel tanks for various reasons.

 

It also cuts down the capacity of the tank by up to 20% and also weighs a bit. It is like steel wool or metal shavings from a lathe.

 

I believe that in order to reduce the incidence of post impact fires a good start would be thorough training and practice in that area as to what you need to do when you find tera firma coming up to meet you at a great rate of knots.

 

As an aside, as to the use of electric pumps, if the engine fitted has a mechanical pump, the electric fuel pump should only be used on takeoff and landing not in normal cruising mode, but thats just my view and I'm sticking to it.

 

For what it's worth that is my two bob's worth.

 

Regards,

 

Rick-p

 

 

[bilby54]

This discussion has generated a lot of good points and has got a lot of grey matter stirring in the pot!

 

Training will help immensely to reduce the risk in an emergency situation but so will self-testing or “desk top” exercises. A recent article in the RAAus magazine gave an instance where engine failure procedures can be practised without being anywhere near the aircraft. What happens when you have learned those procedures faultlessly and then apply them to another aircraft where they do not work effectively or the result that you expect is not the same as what you achieve?

 

If all aircraft fuel and electrical systems were exactly the same then no problem would exist but unfortunately they differ considerably. An emergency could very well happen during takeoff with very limited time to react and stress levels going through the roof. If the only thing that the pilot manages to achieve in the time available is to turn off the fuel cock, then you could reasonably expect that most of the fuel hazard has been contained – remember that Tony was talking about survivable accidents.

 

It is easy to disbelieve signs or information that something could be wrong, especially when we are so familiar with the aircraft that we fly regularly. I checked an aircraft a while ago that had a very noticeable smell of fuel in the cockpit. When I asked the owner about it, he said that it always smelled a bit when you first got in but it goes away after a while. He was effectively ignoring a warning sign due to familiarity with the aircraft and its dangerous situation.

 

I mentioned in a previous post that I grounded an aircraft because of a strong fuel smell while in the air. This aircraft is fitted with a fuel flow indicator and an electric fuel pump located under the internal fuel tank. In normal cruise, the fuel flow readout is around 12 litres per hour but if the electric fuel pump is on, it indicates around 18 litres per hour. The pressure from the electric pump over-rides the carburettor float and fuel flows out of the bowl vent pipe. I checked the fuel line on the discharge of the pump and found that it seeped fuel when the electric fuel pump was on.

 

If an engine failure occurred in this aircraft and the pilot only managed to close the fuel cock before hitting the deck, then it is quite possible that a fuel line could blow off during impact. Lets also assume that the pilot has survived the accident and has detected a strong smell of fuel in the cockpit so turns off the master switch. The fuel air mix within the confines of the cockpit and the arc caused by turning off the master could well erupt and turn the situation into a “brew up”. There are probably many ways that these types of situations could pan out but the main thing is to know the system that applies to the particular aircraft that you are flying.

 

If you think that it is not safe then either tell someone or fix it but don't fly it.

 

B54

 

 

[Ben Longden]

Rick-P said "Some have argued that if you turn off the fuel to a 912 and forget to turn it on at start up you will get of the ground before the engine stops. I don't know if it is true but it really isn't relevant, is it!"

 

I decided to test this one day - ON the ground I might add, and taxied from the front of the club rooms to the hangar. The engine was coughing and spluttering before I even got halfway, which is only 200 metres.

 

The test reinforced to me the training about physically dip checking the bloody fuel is there, IN the tanks and that the relevant taps are on.

 

The training in this area is, to me, not some instructors whim, but an instructors desire to see that you learn to fly safely.

 

Ben

 

 

[Guest Flyer40]

Ben, the incident logs contain many incidents where the scenario Rick describes has occurred. A lot of aircraft have managed to start, taxi, take off and then loose power at about 50 ft.

 

Pipers are notorious for it, because the fuel selector hides behind the pilots leg.

 

 

[Guest TOSGcentral]

Oh Dear! Can we go once again through some basics please – and they are all firmly in the court of “Airmanshipâ€Â.

 

 

Checks are a fundamental part of Airmanship and Airmanship both keeps you alive and adds to your knowledge store as well as situational awareness. Remember that we are just human beings so are prone to error – we have to invent ways of at least countering that condition and Checks are an important part of this.

 

 

Fuel management is no problem at all – if it is done, or can be done! It may not be possible to do full fuel management if your aircraft does not have a master fuel cock – or – you were trained on a type that did not and take your habits on with you to other types. The situation becomes more complex with a multi tank selector aircraft and you need that basic instinctive “fuel management†to automatically deal with the situation.

 

 

OK – for many years I have founded responsible Airmanship on a very simple four part check that I intend to once again elaborate on here.

 

 

When you get into the aircraft and are seated and apparently ready to do something then you check the following before you do ANYTHING (which is actually the time honoured pre hand swinging check). I term it the “clear the cockpit check†to ensure that the aircraft is both inert but is also capable of what you intend it to do

 

 

Brakes ON. (or chocks or whatever).

 

 

You may not have brakes but one day you will and this should also act as a memory jogger that your aircraft that you intend to move is not firmly anchored to the planet via tie downs or will tip on its nose because it has chocks under the wheels!

 

 

Not important? On the forums recently there was an account of a Cessna towing a concrete tie down block into the air. In addition, at a Watts Bridge fly in, one guy who was so anxious to be the first aloft that morning, hand started his aircraft with the throttle wide open and it performed a suitable replication of a control model on very short lines while casting alarm and despondency amongst the owners of the valuable machines tied down both sides of it!

 

 

Fuel ON. Visually check that the fuel master cock is actually on and you will not follow up with the embarrassment of running out of fuel when taxiing or even after take off in types with long fuel lines and not much distance to the take off point.

 

 

Switches OFF. Methodically visually/manually check that all switches are off including services and avionics.

 

 

Throttle fully CLOSED. This has to be the culprit of so many situations yet is so easy to do! You DO NOT start an engine with the throttle other than closed or set for start! But people repeatedly do and it does not matter if they are hand swinging (which granted is more exciting) or using an electric start.

 

 

Once again at a Watts Bridge fly in the owner of a Flight Star insisted on taking the aircraft into the camping ground so he could be near the love of his life overnight! Next morning he had started it with the throttle wide open and the machine began going walk about – with intent to reach flying speed. It was manually wrestled into submission by a suitable number of brawny onlookers before colliding with a tent full of six kids!

 

 

Back in UK and many moons ago, an Auster driver did the same thing, the aircraft jumped the chocks and actually took off, climbed and then settled down in a gentle turn from which the wind then drifted it out to sea – into the busy cross Channel airlanes!

 

 

An RAF fighter squadron was scrambled once the aircraft was clear of land and spent an interesting time demonstrating that it took a front line squadron 20 minutes of cannon fire to shoot down an unoccupied and defenceless aircraft. I suppose there were questions back in the mess about that!

 

 

None of those checks are complicated, hard to remember and are easy to do. But they lead to other things, hopefully automatically.

 

 

Pre take off checks should include a full fuel survey – tanks selected, contents, endurance and pumps

 

 

Pre landing checks should be the same.

 

 

With that solid management Airmanship basis behind you it is then not difficult to add these to an emergency close down that could save you being BBQ’d in an otherwise survivable situation. If you cannot automatically clear your panel and systems in five seconds then spend some time practicing! Just switching off the ignition on an otherwise failing or dead engine is just not bloody good enough! You need ALL the electrics off and both the fuel supply and pumps off! You need to be just flying a glider!

 

 

Not being snotty or superior – been there and done that and I had no warning either – just changed mental gears and got on with what I have self-trained myself to do.

 

 

Aye

 

 

Tony

 

 

 

[Arnaud]

On a Redback trike (and other Airborne models) ), how do you get to the fuel tap whilst in the air ?

 

 

[Guest TOSGcentral]

Possibly you suggest to the manufacture that an important flight safety, manual control should be within easy reach of the pilot, in flight, and at a time when it is busy, there is a lot of distraction and the undies may be being compromised??????

 

 

[Yenn]

The most important thing is to have a thorough briefing on the plane before attempting to fly it. Either from someone competent who knows the systems or sit and read the book of words and then sit in the plane and take it all in.

 

Doesn't matter how much you think you know, just make sure you do know.

 

Years ago I flew a demo C172, didn't have any info from the book but had a check pilot alongside. I was used to the C172, so wasn't expecting any problems.

 

On base leg I put in first stage of flap and was surprised to have to keep pushing the nose down because of falling airspeed. The flap lever worked differently to all previous C172's I had flown. It kept going after I had removed my finger from the switch. On that model you have to centre the switch, rather than remove your finger to stop it working. I never trust a Cessna switch after that. I much preferred the old manual flap.