Mike Borgelt

AF447 was in equilibrium straight and level flight. It was going to pretty much stay there if left alone. HOWEVER the copilot (guy flying at the time) would have seen the altitude decrease suddenly (that was still working- the pitot and hence airspeed was lost because all 3 pitot tubes were blocked by ice) because the position error correction got lost with the pitot. I looked all this up. I think that is why he pulled the stick back and he didn't cross check with the attitude and engine instruments before doing so. Maybe he was worried that he'd get into the Mach buffet as a decrease in altitude would imply increased airspeed. The aircraft was heavy and near its ceiling. It then went to hell in a handbasket aided and abetted by Airbus cockpit design and faulty training (not told to use manual trim wheel) . BTW the co-pilot had a fair bit of gliding experience. Done again with the Air Asia A320 a few years later. I'm afraid economics takes first place from safety in airline regulation. Still reasonably safe in absolute terms but not as safe as it could be. See MH370. A friend of mine has a good theory on that and it has got him permanently banned from pprune which is now owned by a consortium including Boeing.

See what I wrote elsewhere this morning on this forum about RATIONAL, EVIDENCE BASED REGULATION. All the rules in the world don't stop the "hold my beer and watch this!" mob. The regulator cannot be everywhere at all times especially once you are airborne and the danger with excessive regulation is that inexperienced people cannot differentiate between the sensible rules (usually the ones based on physical science and engineering) and the merely bureaucratic ones designed to find punish scapegoats in the event something goes wrong. Funny thing is that the vast majority of aircraft accidents occur with the paperwork in place.

Flying without instruments in modern aircraft makes about as much sense as learning to flap your arms in case the wings fall off.

Sorry this "Your AoA is now 16 degrees" should read "your AoA has increased by 10 degrees". In reality thermals aren't completely sharp edged so the AoA increase is less than the full 10 degrees and goes away after about 2 to 2.5 seconds. Plenty of time for you to pull the stick back though.

If you built the VH registered Amateur built experimental you can fly in CTA once Phase one testing is complete and you can maintain it yourself (apart from Transponder and altimeter calibrations) if you do the maintenance procedures course. The last bloke I spoke to about that said it was "farcical". Just a nasty little collusion between SAAA and CASA I guess. Some would call it corruption. Once again the experiment has been done. I don't know why everyone is so keen to preserve work for LAMEs. Looked at the average age and the way it is increasing lately? There will soon be few of them. Two of the things I've observed during my life: 1. The human race is very bad at correctly identifying the problem that needs to be solved. People then wonder why the "solution" they came up with doesn't work. 2. The human race will not accept the evidence from experiment if it does not confirm their prejudices, even after exhausting the possible confounding elements in the experiment. For a simple, very accessible confirmation see this forum. Also others are: The global warming hysteria (only unequivocal evidence I can find of the slightly increased CO2 level is that the planet is measurably greener. More plants growing better). Neo keynesian economics. Sorry, borrowing money and spending (wasting) it doesn't make us richer. It creates more debt. Cholesterol causes heart disease. Wonderful how you can pick the 7 countries out of 22 studied on saturated fat consumption to prove your hypothesis when the entirety of the evidence shows no correlation. Causes of the current spate of terrorist incidents.

Horizon isn't good at low altitude for a start. Also not good in non equilibrium or nearly so situations as a measure of stall margin. Now consider what happens when you are at 60 knots in a modern glider and AOA is about 7 degrees. Go around the final turn and your AoA increases depending on angle of bank to as much as nearly 10 degrees. Plenty of stall margin to the stall at 15 degrees, right? Now while you are rolling in to the final turn encounter a sharp edged strong thermal of say 10 knots. Your AoA is now 16 degrees i.e. the glider is stalled or perhaps nearly so. In either case the glider will try to pitch down because of the collapse of the lift on the more forward part of the wing, if stalled or the natural stability will cause the glider to line up on the new airflow direction if nearly stalled. You will have encountered this when enetring a strong thermal and feeling like the tail is being lifted. So the nose tries to go down and if you fly by the horizon or attitude you pull the stick back to keep it level, thus pulling deeper into the stall or actually causing the stall. The progress of the nose around the horizon will also slow or stop giving extra incentive to pull back. You are now looking at the ground starting to rotate in front of you and rush up towards you. Pretty much the scenario of a spin in a Waikerie 2 and a half years ago. The pilot is not a fool but I've been told he has no idea what happened or why and thinks there is a problem with the glider type. Aviation has had a lot of spin in accidents while turning base or final. I had to do a lot of analysis of the physics involved in entering thermals, turning etc while developing the Dynamis variometer over the last few years. I haven't seen the above written up anywhere before. One thing we could do and is being worked on by a group at the University of North Dakota is to stop doing the "square" circuit and use a much shallower bank, 180 degree turn from downwind onto final. Be aware also that encountering vertical air motion tries to do more than just cause the aircraft to rise or sink. The stick commands angle of attack. Subsequent motion of the aircraft flightpath is a consequence of that.

facthunter, aviation isn't reasonably safe because of regulation. It is reasonably safe because we've been doing it for 115 years and learned to improve the technology and methods. The regulators are merely parasites.

"looking out at the horizon should be the main input". That is a good way to get yourself killed by spinning in, in the circuit.

I wonder how much of that $21 million in revenue DOESN'T come from taxpayers?

jetjr, there are no good reasons for the Class 2 medical. The experiment has been done, statistics collated numerous times - IT DOESN'T REDUCE THE ACCIDENT RATE. You are all missing the point here. Get on board with the AOPA push for RAAus style medical for GA, owner maintenance for under 600Kg or whatever weight. 1500Kg sounds good to me. That experiment has been done too in Canada which has had an owner maintenance category since 2003. This was audited by the FAA in 2013 who found the owner maintained fleet to be in at least as good or better condition than the traditionally maintained one. the slogan - RATIONAL, EVIDENCE BASED REGULATION. Then there is no need for RAAus to exist except to promote and educate on the activity. No need for expensive employees defending their rice bowls. RAAus aircraft can then go on the real Australian register not the mickey mouse RAAus one. RAAus's shafting of the RPL/PPL medical, as an act of bastardry, ranks up there with the Meertens/Hall/Middleton approach to the Minister in 2003 to shaft a CASA proposal for a recreational pilot licence for all with the RAAus style medical. They even mentioned that while some may be worried about that, that there was no evidence a Class 2 medical did any good. Glider, ultralight and GA pilots were to be able to get and operate on this licence with the proviso that if you wanted to stay in RAAus or GFA you could continue to do so and operate under the existing rules.

Imagine if CASA/RAAus/GFA had been in charge of the internet. You'd now be using a 4800 baud dial up modem (OK maybe 300 baud), you would need a government issued licence to be an internet user, emails would cost 50c each to send and you would need an expensive licence and government approval to run a website like this one. Allow 6 months for that. There might even be government vetting of all posts. Would probably take 12 working days.

Once again CASA ignores the majority view and chooses the worst option on the table. This is not news. We had a really good airspace system in 2003/4. Didn't listen to the irrelevant blather on area unless you wanted to (near congested airspace a good idea to listen to the radar guy), the rest of the time just tune up the nearby CTAF (if near one) unless just listening on 126.7 which you used at marked and unmarked aerodromes unless another frequency was assigned to it. MUCH better situational awareness. The IFR twin turboprops could simply make their position call going below 10,000 feet on area and then on the CTAF. Everyone knew what was going on. Wrecked by the air Traffic controller trade union thugs and a spineless Minister (John Anderson). This country really does have an unhealthy obsession with radio for traffic separation. Most of us are flying day VFR. Start looking out. I've taken evasive action on a number of occasions while enroute without benefit of radio alerting. May have missed but would have been quite close without action.

It is worrying that Google is working on self driving cars and self flying aircraft. Better work better than Google Chrome browser on my iPad mini which crashed frequently and made the device almost unusable. Boycott Fakebook and encourage your friends and relatives to do the same. There is nothing wrong with phones, Skype, email to stay in touch with friends and relatives and list servers and websites/blogs for things that are of interest to you.

I'm referring to stlmusic.

Good to see someone with sound knowledge of aero and flight dynamics.

facthunter, you are right about widespread ignorance of basic physics. Not confined to aviators unfortunately. Our politicians and bureaucrats wouldn't know the difference between a kilowatt and a kilowatt hour which will have disastrous consequences for Australia's electrical power system.

Newton's Third Law explains the force (lift) on the aircraft. Bernoulli (a reasonable approximation at low subsonic speeds) explains the distribution of that force on the surfaces of the aircraft. Check your frame of reference. It is very easy to inadvertantly swap to another frame without realising it. You see an aircraft flying by. You know gravity is pulling it down so there must be a force (lift) opposing gravity. What do you see in the air around the aircraft? It is moving down behind the aircraft. Newton 3. Now change reference to being in the aircraft. YOU CANNOT DETECT gravity. What you feel is the aerodynamic reaction force on the aircraft distributed according to Bernoulli. Obvious when you think about it as you can vary it at will by moving the stick back and forth. Turbo's post as usual gets things hopelessly wrong. Look up some pressure distributions over airfoils on the top and bottom surface. Most modern airfoils have reduced pressure on BOTH surfaces. It is the integrated difference that counts. The power to weight of an aircraft matters because if you have high power to weight you usually want the aircraft to go fast. To do that you want a thin small wing with low camber to minimise drag. If you have low power to weight and want to carry a load you want to minimise structure weight. This requires a thick wing with a lot of camber to minimise drag as you don't have much 1/2 rho V^2 to work with. I'm not even going to get into the refrigerator theory. How did Enrico Fermi put it to an aspiring young nuclear physics student? "So bad it is not even wrong." Human powered flight will be quite practical in underground caverns on the Moon if the air pressure is sea level Earth normal (forget the bubbles on the surface - micrometeorites and cosmic rays along with solar protons). The Moon will mainly be useful to strip mine for materials for O'Neill habitats where the solar power is 24/7 instead of being unavailable for two weeks at a time unless at the lunar poles on high peaks. Gravity is also what you want it to be on a space habitat. We simply do not know if anything substantially less than one g for long periods is viable for humans. We do know zero g isn't. This is one of the things that should have been done on the ISS but that experiment was cancelled in favour of high school science experiments and torturing astronauts in zero g. "It seems likely that mankind will colonise both the Moon and Mars within the next century, barring nuclear accidents and unmitigated climate change." The risk is more like regressing to a pre techological civilisation (horrible) because of people like Marty. Want to mitigate CO2 emissions? (pointless anyway). Build lots of nukes. Any else is hypocrisy. BTW Marty the air pressure at the average ground level on Mars is 0.6% (6hPa) that of Earth sea level. There is also at least 20 times as much CO2 (95% of atmosphere) over every square meter of Martian surface as there is on Earth. It is very cold.

Take a look at the strakes on the fuselage ahead of the tailplane on the DHC1 Chipmunk. These are also fitted to some Tiger Moths. I think the idea is that at high angles of attack like in a spin, there is a vortex generated by each of them which energises the airflow over the fin and rudder. I knew a bloke (cropduster pilot, now deceased after his last accident) once who spun a Tiger Moth into the ground and lived to tell the tale. The gliding club was hiring it as a towplane. He rented it to do a session of aerobatics and during this noted that it seemed a little reluctant to recover from a spin one way. The other way was fine. Told LAME, who checked the rigging. Next weekend flew it again. One way spin recovery was fine. The other way seemed a little reluctant still. Tried again and it kept spinning all the way into the ground. He turned off the fuel and ignition and tightened his harness and although injured, lived to fly again. Also knew a couple of blokes who were messing about in a Puchacz sailplane and got into a spin at 3500 feet and it would not recover. They were both highest level GFA instructors. Eventually for no known reason it came out and the recovery went down to 350 feet AGL. Lesson is, yes you possibly need spin recovery training fairly early in flight training. Do it in a Pitts or Decathlon, wear parachutes, go to 10,000 over the water or an unpopulated area and if it is still spinning at 5000 feet and you've tried all you can to recover, bail out. Remember the lesson anyway, mentally rehearse it often and NEVER spin accidently because as facthunter says, if you do it accidently it will likely be at low altitude where knowing how to recover will not help. If you are a GFA member you are now required to do spins on every annual check. I consider this a gross intrusion on your personal right to voluntarily select your level of risk exposure. BTW there does not seem to be any evidence that spin training or lack thereof has any effect on the accidental spin in rate. Canada had a PPL spin training requirement for years after the USA abandoned it in 1947 I think. Early in the 21st century Canada did the same after a review of the accident stats showed no difference EXCEPT that the Canadians were losing pilots and instructors in spin training. This was written up in Avweb at the time.

Where is the suggestion of problems in America in the linked article kaz? The federal regulator they talk about is CASA not the FAA. Sounds like the NT fuel supply changed from 100/130 to 100LL and the problems began. There was a discussion on the BD-4 group a while ago and there were problems with old fuel tank sealant. Seems some of the older sealants had troubles with 100LL and no problems with 100/130. If 100 LL indeed has higher aromatic content this isn't all that surprising. This is a pretty good survey of Avgas lead content etc. Avgas - Wikipedia onetrack, your earlier article referred to problems when the lead was removed from petrol. As Avgas has not, in most of the world, had the lead removed, it clearly refers to cars. As do your latest links. They are talking about PoS Ford or Holden motors or similar which run the valves in cast iron heads without valve seats (cheaper to make) which your later links also refer to. Lead in the petrol let the manufacturers get away with this. Aircraft engines with aluminium heads have proper valve seats in the heads which may explain the Swedish aero engine experience with unleaded Avgas. Refer to the Wikipedia article on the Hjelmco fuel. To sum up, yes, lead prevents valve seat erosion in engines running the valves in cast iron heads without hardened valve seats. With hardened valve seats it seems there is no problem, as attested by the Swedish unleaded Avgas experience. "after 25+ years has flown for millions of flight hours in thousands of aircraft and in any weather /technical condition. Removing lead from an engine improves life time of the valve system. An engine using 100 LL may have 2000 hours for TBO. The same engine using our unleaded grade 91/96 UL usually runs 3000 hours between TBO" In aero engines lead deposits can build up on valve stems leading to sticky valves which can lead to the valves burning as they don't seat properly. The contact between the valve seat and the valve conducts head away from the valve during combustion.

Only time I've had plugs short it was due to metal balls of lead.

This bit? "Anti-valve seat recession additives The lead additive (TEL), in addition to its primary purpose of increasing octane number, also provides a critical wear-reducing function by depositing a thin protective layer of lead salts on valve seat surface. Without this protection, exhaust valve seats wear or recede into the cylinder head. After banning of use of TEL in 1990s, the problem of wear appeared. The problem of valve seat recession is overcome by the use of chemicals based on potassium, phosphorous and manganese salts. The combusted metal salts act as a protective lubricant and prevent the direct metal-to-metal contact that would otherwise cause high wear. " Not specifically referring to aircraft and in fact seems to refer to cars and the removal of lead from car fuel. You also need to explain the Swedish experience with aircraft engines I referred to: "Sweden pioneered with unleaded grade 80(octane) in 1981. This fuel was also used by the air-force. In year 1991 our second generation unleaded AVGAS grade 91/96 was launched. This fuel is still used in Sweden and also elsewhere. In Sweden regularly about 80 % of the piston powered fleet is using this fuel, which after 25+ years has flown for millions of flight hours in thousands of aircraft and in any weather /technical condition. Removing lead from an engine improves life time of the valvesystem. An engine using 100 LL may have 2000 hours for TBO. The same engine using our unleaded grade 91/96 UL usually runs 3000 hours between TBO" Maybe the Hjelmco fuel has added potassium, phosphorous and manganese salts? Seems it is the lead salts or other compounds being deposited does the protecting. Kind of hard to argue against the Swedish experience. Here's Richard Feynman in scientific method: If you've never heard of him you should look him up.

Source?

More than you ever want to know about lead in Avgas and the replacement effort : https://repository.tudelft.nl/islandora/object/uuid:d7c5a6f6-f49f-432b.../download Here's a relevant part on the necessity for lead in avgas from Lars Hjelmberg - Hjelmco. Hjelmco have been supplying unleaded Avgas in Sweden for years. Page 113/114 of the report. Answers from Lars in quotes. Appendix 1E Hjelmco BRGDS Från: Ali Noormehr [mailto:[email protected]] Skickat: den 28 september 2015 02:08 Till: Lars Hjelmberg - Hjelmco Ämne: Re: HjelmCO.se HELLO, As known, the AVGAS 100LL is being viewed as a common fuel blends in the general aviation industry. Given the fact that a large portion of lead emission is from the general aviation, the EPA is urging the involved organization such as operators, refiners, manufacturers to stop using 100LL in the near future. To do this, the 100UL type has been introduced as the best alternative for 100LL. My questions are as following: - - TEL is being viewed as a critical component in the 100LL composition in order to avoid aircraft engineknock. Given the fact that the 100UL contains no TEL, is this fuel type still recommended for use in the general aviation? https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=10&ved=2ahUKEwjt97_4h_PdAhUYQd4KHQ6tDKYQFjAJegQICRAC&url=https%3A%2F%2Frepository.tudelft.nl%2Fislandora%2Fobject%2Fuuid%3Ad7c5a6f6-f49f-432b-b489-c4796bb454f4%2Fdatastream%2FOBJ%2Fdownload&usg=AOvVaw0nTCBjE8gV6ykI2TfThR71 " No-one knows - there is still no production standard for an 100 UL AVGAS – so no-one knows the outcome." - - Study shows that an increase in the aromatic level is the only way to replace the TEL. Is that true?? " No" Could you tell me more about the aromatics? I know only the Toluene as aromatic, are there more aromatic components in the fuel composition? "There are several aromatics that may increase octane-numbers. Some of them can not be used at all - others cannot be used in desired amount. Aromatics cause fuel to burn slower, has lower energy content and cause deposits. " - - Usage of TEL in the fuel composition is beneficial for some of the engine-parts such as enginevalve. "Not correct." The question arises, are there any other engine-parts that could be affected as result of TEL absence? "TEL is not needed in AVGAS 100 LL for any other reason than to increase octane numbers. Sweden has unleaded AVGAS in use since 1981." - - What about the distribution and infrastructure? Is there any change needed in the current infrastructure as results of 100UL deployment? "This can only be known after knowing the final composition of the fuel – which currently is unknown. Using an unknown component in the aviation field – may cause damage to existing tanks, gaskets, hoses etc." - Did you ever run an aircraft engine with an unleaded fuel type? If yes, does this fuel type have an improving impact on the engine performance? "Sweden pioneered with unleaded grade 80(octane) in 1981. This fuel was also used by the air-force. In year 1991 our second generation unleaded AVGAS grade 91/96 was launched. This fuel is still used in Sweden and also elsewhere. In Sweden regularly about 80 % of the piston powered fleet is using this fuel, which after 25+ years has flown for millions of flight hours in thousands of aircraft and in any weather /technical condition. Removing lead from an engine improves life time of the valvesystem. An engine using 100 LL may have 2000 hours for TBO. The same engine using our unleaded grade 91/96 UL usually runs 3000 hours between TBO" --------------------- Note the last.

Geez, the fuel formulation got changed (Going from 1% to 16% aromatics and reducing lead seems like a big change - the fuel might meet spec but was any testing done on real engines or just laboratory spec testing?) and they are having trouble. Just go back to the old formulation. If that doesn't fix it check out the source of the new valves and seats and test for material properties/manufacturing methods. They were quick enough to ground aircraft for the Mobil avgas contamination issue and happy to screw over Jabiru on flawed evidence.

I know of glider towplanes have used a shandy of 25% avgas, rest unleaded and gone to 2000 hours before overhaul. O-540. Pretty severe service too.