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Phil Perry

CTSW Forced landing (uk )

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Both crew were uninjured when a CTSW  aircraft carried out a forced landing following engine failure. 

 

The conclusion by the AAIB seems to point to an 2012 Service Bulletin regarding fuel management on this type; of which the pilot was unaware .

The Composite aircraft was damaged beyond repair .

 

https://pagefast-9.dmanalytics2.com/click?u=https%3A%2F%2Fassets.publishing.service.gov.uk%2Fmedia%2F5c1117ede5274a0ad4ea6615%2FFlight_Design_CTSW_G-KEVK_01-19.pdf&i=9&d=6W3ZZY2X-80X5-4Z15-YZ83-Y0V14UUV184Z&e=airside4me%40gmail.com&a=82V37503-Z333-490Z-YW90-377X02Z1U98V

Edited by Phil Perry

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Interesting report, Phil. Is that aircraft built from carbon? That might explain why it's considered a write-off .

Many Jabirus with far worse damage are repaired and returned to the air: one advantage of being constructed from low-tech fibreglass.

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I will probably cop some flack for this, but I'm very happy to have individual "taps" for each wing tank.

I don't need to fly out of balance on purpose. 

Can run an individual tank down to a certain known level and isolate it there, knowing 100% there will be no transfer between tanks and that exact level will remain.

I can leave more fuel in the right tank to help keep the aircraft balanced and wings level in flight, one up.

Both tanks isolated while parked makes someone stealing the fuel harder. Isolated taps and locked doors. (They need to syphon and not just drain tanks)

If parked across a slight incline, fuel does not cross transfer and drain out the breather.

When taking off with both tanks full, I can run each for 10 mins, taking the top off each.

 

I have also run a tank empty in flight (controlled situation) and fuel did NOT begin to flow to the engine when the "full" tank tap was opened. 

Only when the empty tank tap was closed.

Meaning the mechanical fuel pump kept trying to pull from the empty tank until it was shut off.

(This seems to be the reason for this crash but they had no tap to shut off on the empty tank to get fuel flowing from the full tank.

The horror of knowing you have fuel in one tank but can't get it to the engine!)

For me, after closing the empty tank tap it took about 2 or 3 seconds for the engine to resume to normal operation.

Note. The engine never stopped running, it lost power and "spluttered".

As I knew exactly what was happening, my corrective measures were instant.

Quite possibly in a "real" situation the engine would have stopped as the shock of the situstion and fault finding would have taken time. 

 

 

 

 

 

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15 hours ago, Old Koreelah said:

Interesting report, Phil. Is that aircraft built from carbon? That might explain why it's considered a write-off .

Many Jabirus with far worse damage are repaired and returned to the air: one advantage of being constructed from low-tech fibreglass.

 

I think the report says that the airframe is largely made from Carbon Fibre, I'll have to have another read.  This is a very short report by AAIB standards, being only four pages, however, had the incident resulted in any Fatalities, It would have been more comprehensive.   Bad form for the Owner / Operator / Annual Permit to fly inspector in not having checked for any unapplied  service bulletin updates though.    Amazing in fact.  MIND YOU. there may have been a paperwork problem with the aircraft documents, as the Service bulletin referred to was in 2012, whereas the accident was in September 2018. . .  mitigation ?

 

Insurance ?  Contributary negligence ? . . .  Too early to say probably. . .

Edited by Phil Perry
Additional info.

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10 hours ago, Downunder said:

I will probably cop some flack for this, but I'm very happy to have individual "taps" for each wing tank.

I don't need to fly out of balance on purpose. 

Can run an individual tank down to a certain known level and isolate it there, knowing 100% there will be no transfer between tanks and that exact level will remain.

I can leave more fuel in the right tank to help keep the aircraft balanced and wings level in flight, one up.

Both tanks isolated while parked makes someone stealing the fuel harder. Isolated taps and locked doors. (They need to syphon and not just drain tanks)

If parked across a slight incline, fuel does not cross transfer and drain out the breather.

When taking off with both tanks full, I can run each for 10 mins, taking the top off each.

 

I have also run a tank empty in flight (controlled situation) and fuel did NOT begin to flow to the engine when the "full" tank tap was opened. 

Only when the empty tank tap was closed.

Meaning the mechanical fuel pump kept trying to pull from the empty tank until it was shut off.

(This seems to be the reason for this crash but they had no tap to shut off on the empty tank to get fuel flowing from the full tank.

The horror of knowing you have fuel in one tank but can't get it to the engine!)

For me, after closing the empty tank tap it took about 2 or 3 seconds for the engine to resume to normal operation.

Note. The engine never stopped running, it lost power and "spluttered".

As I knew exactly what was happening, my corrective measures were instant.

Quite possibly in a "real" situation the engine would have stopped as the shock of the situstion and fault finding would have taken time. 

 

 

 

 

 

Interesting tale with regard to your 'Experiment' Mr. Downunder Sir.   Your last comment was most prescient,  You KNEW that it was going to happen and were prepared for it.   This luxury, as your comment points to, is that Many pilots are NOT prepared for certain occurrences, and have to take time to evaluate the situation and carry out checks to identify the most probable cause.. .

 

Rather like the 'Sully' movie ( Very LOOSE Analogy here ) where there was an argument raised at the investigation ( I realise that they Did NOT give him s hard a time as was shown in the film )  that, OK, maybe he could have made it back to a couple of airports following the Bird strike, but nobody Warned him or his First Officer ( Handling) that it was liable to occur.  NOW - This bit of the movie script might have been written by Clint Eastwood ( The Director of the movie )  or it may have been taken from the actual investigation I don't Know,. . but it Does highlight the situation that you have alluded to. . .   'Nobody Warned me'  .  .this was indeed the case for the pilot of the CTSW, especially as he had no knowledge of what might happen when flying out of balance with minimal fuel in one wing tank and a lot more in the other wing, considering the open 'Cross flow' fuel system design of that machine.

 

I have been reading that there have been a number of such occurrences with the CT and CTSW ( SW = Short Wing) types, which, as fortune would have it, dd not result in Unintended nor planned Re-interface with the ground due to fuel starvation. . . I concur with your thoughts on Switched tanks, with isolator switches too. . .the old C-150 had a rather sensible Left tank / Right tank switch, with a main fuel isolator tap as well.. . . Always worked fine for me. . .  Why Later designs did not adopt this as a sensible standard is a mystery to me, same with the lack of Gascolator Drain taps under the wing tanks to check for water during the preflight. . .  I Might buy an Aeroprakt VIXXEN for around £85K,. . .But I wouldn't even bother with a CT.  ( Personal Preference you understand )

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Phil, while the basic Savannah has 2 tanks (permanently connected) the Australian version generally has 4, and we in NZ seem to have inherited that local standard.

I have had a fair few discussions with various people as to how to best valve 4 tanks.

I can confidently report that a large proportion of light aircraft and microlight pilots have had it drummed into them that you never turn fuel off...end of story.

And it's actually very difficult, and usually futile, to try and have a conversation about multiple tanks with those pilots. They just know better. Or perhaps they just feel safer with everything valved on.

 

 

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I should add that it seems to me the key factor is the understanding of the fuel system and behaviour in the specific aircraft you are flying.

 

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I recall hearing that some aircraft (Jabiru in this case) had individual wing tank taps deleted due to the fact that with them installed it required one tank full, one tank empty spin testing.

Reckon that might be too much for many structurally.

Edited by jetjr

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1 hour ago, jetjr said:

I recall hearing that some aircraft (Jabiru in this case) had individual wing tank taps deleted due to the fact that with them installed it required one tank full, one tank empty spin testing.

Reckon that might be too much for many structurally.

That would surprise me, JJ.  I've heard a test pilot describing the scores of spin test in all possible configurations he did in Jabs. After a few dozen spins even he, an experienced ex-RAAF pilot, would throw up. 

The Jabiru airfare might be one the most heavily-tested of all ultralights.

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yes that's true, lots of testing done and done well, but not with one wing tank empty and one full which changes things a lot.

Also largely done on short wing versions I think.

Early wing tank versions has gascolators and a dual tap near brake handle. Still see the odd one with "sharks fin" centre vent, gascolators were removed after a couple of problems, vented tank caps and header tank installed under pax seat. 3 port individual taps near wing roots, reckon they had 2 in one out,  later the handles were removed. In J230 the header tank moved to rear and taps deleted altogether, Little clamps supplied in toolkit though.

 

There was some interesting videos on line on these spin tests.

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 The fuel disposition might affect which way it tends to spin at entry.. Spinning is not hard on airframes.  (Unlike spiraling) the maximum loading happens during the dive recovery at the end and can be about 2 point 5  G if you are careful. That's not going to stress anything much as regards the aeroplane structure. More likely to affect crosswind capability on one side. Nev

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I seem to recall one local Ultralight fatal crash (in the 1980's - at Beverley, W.A.), which ended the life of a very experienced BASI investigator, was deemed to be simply the result of failing to ensure a fuel tank tap was turned on.

The engine cut out at a critical height, right after takeoff, and the result was an ultralight that promptly dropped like a stone, due to stall.

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3 hours ago, onetrack said:

 crash was deemed to be simply the result of failing to ensure a fuel tank tap was turned on.

 

Crash was caused by pilots failure to maintain airspeed, the engine failure was a casual factor.

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12 hours ago, Thruster88 said:

Crash was caused by pilots failure to maintain airspeed, the engine failure was a casual factor.

I'd be interested to read the accident report on that one. . .

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2 hours ago, Phil Perry said:

I'd be interested to read the accident report on that one. . .

I'd be surprised if the was one. Tax paying Australians seem to come last in any investigation here at times, and anything foreign (illegal immigrants & missing airliners) and/or media worthy and politically advantageous are the first priority unfortunately......

 

Edited by Downunder

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I had interesting sort of related experience yesterday.

 

20 minutes into a 50 minute trip cruising at 4500 with tanks at;  Left 15/45  Right 45/45 litres (LH was about half full when I departed)

I planned to run the another 20 minutes of the trip on the LH tank but switch to RH on decent before entering the the circuit and have an almost full tank or the return trip. 

(this worked out well as I had a light passenger for the first leg but not the return leg)

 

I was getting some light turbulence at 4500ft which was making my passenger uncomfortable so I decided to sneak up a bit higher. I was just on a way-point that would put me on odd levels hemispherically so I decided to look at 5500ft rather than letting down down to 3500ft.  I was also watching some traffic on ozrunways that was slightly below and on an intersecting course from the right. 

 

I set up a 500ft/min climb and was watching out the RH window for the traffic (probably fixated on it to be honest) when suddenly I heard a splutter and felt a strong vibration. Now I had felt this once before in the past several years ago when I was too eager switching off a tank during a change rather than running both for a minute, so I knew exactly where to look - and yup fuel pressure bouncing on zero.

 

I quickly open the right tap and almost instantly the pressure rose and the engine resumed normal running.  (I should have put the boost pump on also)

A minute later I shut off the left tank.

 

On landing I dipped my tanks on arrival to confirm these levels were correct. Then on the return leg, just to prove a point I ran for 20 minutes on that LH tank in level flight at (6500ft) without issue. At my final destination I filled the left tank with a top up of 36 litres. Meaning about 9lt when I landed the second time. 

 

I'm a high wing - gravity fed to boost pump (off at the time) - with a brand new mechanical fuel pump (old one was time expired)

I can only assume that climb attitude and mild mild turbulence unported the LH tank and let some air into the line. 

 

The thought in my mind after all this is that it would have been less fun at 500 ft!!  I know there was an accident involving an Airtourer (I think) where a tank unported on take-off during circuits.  But I would not have expected 15/45 litres to unport.  I may have to rethink my fuel management.

 

I do feel a bit sorry for the CT in the original story. The European 450kg certainly limits the fuel you can carry.

 

 

Edited by BlurE
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My fuel wing tank port is at the rear of the tank. In cruise the bottom of the tank slopes down slightly to the rear.

My fear  ( but it has never happened) is that on descent the remaining fuel runs to the front of the tank uncovering the port.

I always run on the fullest tank during descent to manage that risk.

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12 hours ago, Phil Perry said:

I'd be interested to read the accident report on that one. . .

It didn't show in ATSB search for Beverley, ultralight accidents are not often investigated by the atsb  but this fuel related one happened at Beverley.

https://www.atsb.gov.au/publications/investigation_reports/1984/aair/aair198404508/

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1 hour ago, Thruster88 said:

It didn't show in ATSB search for Beverley, ultralight accidents are not often investigated by the atsb  but this fuel related one happened at Beverley.

https://www.atsb.gov.au/publications/investigation_reports/1984/aair/aair198404508/

 

These IO-520 engines chew thru the avgas at a frightening rate. For flight planning I use a rule-of-thumb 60 LPH, (which is leaned and 75% HP), while for slower flying the fuel burn is 52 LPH, also leaned. Flying it at 65% thus gives some additional margin.

 

ATSB claim the flight was made at 3000 ft, without leaning. I'd assume that the pilot used 65% power. Now 52 LPH + 24% for nil leaning = 65 LPH. So, on departure, the absolute minimum fuel load on board should have been 155 mins x 65 LPH + 45 mins fixed reserve.  So, 169L + 49L  = 218L. 220L was the fuel load estimate.

 

By any standards, this was always going to be a close call because the pilot claims to have only 'inspected' the fuel. Does this mean dipped with a calibrated dipstick? Was there an onboard fuel computer, and did the pilot know how to use it? Or, did the pilot simply 'eyeball' the fuel gages, peep into the tanks, light the fires and blast off on this air trial.

 

No wonder that fuel mismanagement accounts for 55% of Australian incidents/accidents

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The Beverley fatality I mentioned was not the Cessna crash, it was definitely an ultralight, and it was around the early-to-mid-1980's.

However, that was the era before RA-Aus. BASI was still operational then, and I understand they investigated the ultralight crash.

CASA was not founded until July 1995, and ATSB was not founded until July 1999. It appears that many earlier BASI-investigated crashes were not transferred across to CASA or ATSB online records.

I would have to go back through the newspapers of the era to try and find the media reports of the fatality. Unfortunately, newspaper records of the 1980's are not available online.

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