Dafydd Llewellyn

I'd say it depends on what you're flying. The Chinese method (wun wing Lo) works with most high-wing taildraggers, and it worked on the Chippie, also. Don't try it on a V-tail Bonanza. There's no general rule as to which is best, so you need to be able to do either proficiently, if you fly more than one aircraft. On the whole, I tend to use the wing-low method on taildraggers, and crabbing/kick off with tricycle undercarriage - but the wing-low method works OK for Jabirus, too, because they need to be landed with the nose wheel well off the ground. So this is a fairly stupid thread.

thanks for that teckair and dafydd - HORSCOTS is googable.......................... we've come a long way .............. for a clever country ! (actually Qld as well - also being a smart state also (if you believe the pollie rhetoric))

I suggest that you work on the assumption that the cowl will at some time contain CO; and concentrate on preventing that CO from entering the cabin. Leakage in the firewall is target No. 1; there are various semi-flexible goos available for that.

Target No. 2 is any exhaust-muff cabin heater. They are a CO incident waiting to happen. There are no really simple alternatives; if you operate in a cold climate, maybe flying boots? And a really good CO detector.

Target No. 3 is, improve the cabin door seals, and ensure sufficient freash air is available from a clean source, so that air is trying to escape from the cabin, not being sucked into it.

Obviously, there are many ramifications to these general principles; they are pretty obvious, so I don't want to enter into a long dissertation on them

Don't use it on the exhaust; use it on the firewall.

Yep. Thems was the days before HORSCOTS took effect.

Is that the same for everyone? A couple of us had an excess CO situation in the workshop one day due to lack of ventilation whilst using a big diesel burner and I can't say there was any headache, we both got extremely sleepy and groggy. We were even aware it could happen (planned to switch off the heater shortly) but it snuck up before we realised that was the scary part.

The danger from CO in an aircraft can be more subtle than that article indicates. In the accident I described, it seems likely that the pilot realised he had a problem, and closed the throttle to slow down (that was definite, both from witness reports and the position of the vernier throttle control from the wreckage), so he could open the canopy. In wrestling with the canopy, he may have hyperventilated (happens much more readily if you are suffering from the effects of CO) and lost consciousness. The aircraft rolled inverted and headed for the centre of the Earth, and simply came apart from sheer overspeed (after descending about one mile from its cruise level). This requires less than half the lethal concentration of CO in the bloodstream, from what I was able to dig up. CO is BAD NEWS.

ERhmm . . . The FAR 23 limit is 50 ppm (same in most if not all certification standards); anything above 25 ppm will give you a cracking headache. However, it looks like a good form of cockpit alarm device. Who can calibrate them, and wot does it cost?

Wonder what these cost: http://www.draeger.com/sites/assets/PublishingImages/Products/cin_pac_7000/Attachments/pac_7000_pi_9046061_en.pdf - I'd want the one with 35 ppm & 50 ppm alarms.

Thanks Daffyd, it makes you wonder how the Gazelle got through certification especially the part refering to controls being easily identified. It is very easy for students to miss identify the carb heat knob and pull on the choke or cockpit heater. I will read the rest in depth.I don't want to take up all of your time here but I am curious as to how the european aircraft can be certified - be it GA or RAA - in Australia without having a carburettor heat system? If the carb heat system is replaced does it have to be exactly as the original or substantially the same? As parts are dropped by manufacturers or improvements made or redesigned but that is what is available to use now, how does that change the certification? If the cabin heater is removed from the Gazelle because the airbox is no longer made as an example, does that make it non compliant with certification?

Re the European aircraft, same story; if it's an LSA aircraft, the ASTM design standard simply says:

"7.5 Induction System—The engine air induction system shall be designed to minimize the potential of carburetor icing."

Just HOW it minimises the potential, is anybody's guess. With FAR 23, you are told exactly how, and how to prove it. I'm somewhat underwhelmed with the certification standards for LSA aircraft, as you will readily understand. Faced with something like the ASTM requirement, we'd inevitably apply the FAR 23 methodology, if we were doing this in Australia - if only to minimise the product liability. I have a feeling it's a lot looser in Europe. I tend to see the LSA class as junk, candidly, because this sort of thing is all through them.

If you replace the fuel pump with a later part number from the 912 parts catalog, that happens to have a double diaphragm with a drain tube (the Jabiru had this from day one, by the way), then you are not making an unapproved modification to the design, so long as you do it IAW the factory instructions. Look at any Cessna or Lycoming parts catalog, and see how they have handled up-dating of components from external suppliers; if it's in the parts book, it's legal.

Removing the cabin heater from a Gazelle would be a modification, and unless it's covered in the manufacturer's data, you need an approval for it; see CAR Part 2A.

Thanks fella's.Daffyd, could you clarify where it is a requirement for the carby heat system to be manually operated so as I can understand the certification system please? I have spoken to a lot of people who were involved in the original development of the Gazelle and the concept of making more like a GA trainer with carby heat. The Gazelle is a great little aircraft but the engine installation and set up is applling compared to the european set ups.

 

Here's the FAR 23 version; the Gazelle was certificated to a lesser standard, but they all say much the same on this point. I've deleted the irrelevant bits:

 

§ 23.1091 Air induction system.

 

(a) The air induction system for each engine must supply the air required by that engine under the operating conditions for which certification is requested.

 

(b) Each reciprocating engine installation must have at least two separate air intake sources and must meet the following:

 

(1) Primary air intakes may open within the cowling if that part of the cowling is isolated from the engine accessory section by a fire-resistant diaphragm or if there are means to prevent the emergence of backfire flames.

 

(2) Each alternate air intake must be located in a sheltered position and may not open within the cowling if the emergence of backfire flames will result in a hazard.

 

(3) The supplying of air to the engine through the alternate air intake system may not result in a loss of excessive power in addition to the power loss due to the rise in air temperature.

 

§ 23.1093 Induction system icing protection.

 

(a) Reciprocating engines. Each reciprocating engine air induction system must have means to prevent and eliminate icing. Unless this is done by other means, it must be shown that, in air free of visible moisture at a temperature of 30 °F.—

 

(1) Each airplane with sea level engines using conventional venturi carburetors has a preheater that can provide a heat rise of 90 °F. with the engines at 75 percent of maximum continuous power.

 

This has to be tested in flight in the manner described in FAA Advisory Circular 23.8 para 256 (now at amendment C, I think; the Gazelle was tested at amendment A); that's too big to include here, but you can download it from the FAA website, www.faa.gov

 

The necessity for manual operation comes from the method of testing; you cannot do the tests without being able to select full hot or full cold. "Manual" does not necessitate a knob & a bowden cable; you could do it via some servomechanism, but you'd bring down on your head the task of proving the reliability of the servomechanism.

 

There's also:

 

§ 23.1157 Carburetor air temperature controls.

 

There must be a separate carburetor air temperature control for each engine.

 

and

 

§ 23.777 Cockpit controls.

 

(a) Each cockpit control must be located and (except where its function is obvious) identified to provide convenient operation and to prevent confusion and inadvertent operation.

 

(b) The controls must be located and arranged so that the pilot, when seated, has full and unrestricted movement of each control without interference from either his clothing or the cockpit structure.

 

© Powerplant controls must be located—

 

(1) For multiengine airplanes, on the pedestal or overhead at or near the center of the cockpit;

 

(2) For single and tandem seated single-engine airplanes, on the left side console or instrument panel;

 

(3) For other single-engine airplanes at or near the center of the cockpit, on the pedestal, instrument panel, or overhead; and

 

(4) For airplanes, with side-by-side pilot seats and with two sets of powerplant controls, on left and right consoles.

 

(d) The control location order from left to right must be power (thrust) lever, propeller (rpm control), and mixture control (condition lever and fuel cutoff for turbine-powered airplanes). Power (thrust) levers must be at least one inch higher or longer to make them more prominent than propeller (rpm control) or mixture controls. Carburetor heat or alternate air control must be to the left of the throttle or at least eight inches from the mixture control when located other than on a pedestal. Carburetor heat or alternate air control, when located on a pedestal must be aft or below the power (thrust) lever.

The one I have is simply a warning device, which is of the "none/some/ LOOK OUT!" type, sold by Global Aviation. It wasn't what I really wanted, which was a calibrated instrument reading in ppm, that I could use to give CAR 35 approvals (I have previously used the old Drager type, which uses a glass tube with crystals in, you use one tube each time you make a measurement - but calibration is not an issue with them). A lot of local councils have one. I've investigated one accident which was a mid-air break-up, almost certainly due to pilot incapacitation due to CO; it's more of a danger than people commonly realise. The damn fool medical examiner dismissed it on the basis that such indications as were forensically possible did not indicate a lethal CO level - completely ignoring the fact that the ground can get in the way long before the pilot dies from excess carboxyhaemoglobin.

Hi All,I'm presently dealing with some intergranualar corrosion on a 2020 T3 spar cap extrusion. I need a very small quantity of Deoxidine 624 and Henkel W01 to clean up, 100ml of each one would be heaps.

 

Does anyone know where I might be able to find this in SE Qld? Henkel don't sell deoxidine in less than 20L. If a member has some I could purchase a smaller quantity off that would be great.

 

Also I'll likely need to talk to a CAR35 (or Part 21 section M I think it's now referred to!) engineer - can anyone recommend one that is GA experimental friendly. I've had to take 0.030" at the deepest spot off the top of the 0.190" T extrusion.

 

Cheers

 

Tim

From a basic engineering standpoint, the questions are:

(1) Where along the wing span is the damage? Most aircraft are critical at the wing root, if it's a cantilever wing, or at the lift-strut attachment, if it's strut-braced, and usually have some margin in the spar cap away from the critical locations. So whether or not your repair is permissible will depend on these factors.

(2) The issue is not how deep you had to go to clean-out the corrosion, but by how great a percentage is the cross-section area reduced (and mainly, that applies to the top of the T, ignoring the vertical leg)

(3) Is it on the top or the bottom cap ? (i.e. is it normally loaded in tension or compression in flight)

(4) Does the aircraft have any fatigue life limits?

You'd have to provide that sort of info to an engineer, to get any sort of answer.

You also have a problem in QLD, because one cannot legally give engineering answers without being registered with the QLD Board of professional Engineers.

If you stop learning, you're dead, even if they haven't yet buried you. Some people die at 20 and get buried at 70 odd.

BTW important to note.....These electronic CO detectors have a limited lifetime sensor, in general they are only good for 5years then ned to be replaced.

 

Andy

That's up to you. It would work for some people, but I've come across some that would need a baseball bat. There are too many things people should not grab or stand on, to lever themselves up to get the shot; and too many places a camera can get caught in the works if they drop it (not as bad nowadays, with miniature digital cameras, of course). The famous example was a C150 that bunted into the ground, evidently because the passenger put his foot on the elevator control yoke in his excitement to get a shot of something they were flying over. A really dedicated photographer is unconscious of everything except what's in his viewfinder. That doesn't matter if he's in the back seat of a Cessna or Piper, where there is nothing he can do much harm to.

Unless they are also a pilot, or otherwise experienced in aircraft; I should have qualified that. A joyrider with no previous aviation experience, who gets aboard brandishing a camera, is potentially dangerous, if they can put a hand or a foot on the controls. If you want to carry somebody like that in the right-hand seat, remove the controls from that seat. If your aircraft does not have removable controls, my advice is do not carry that sort of passenger.

Outwardly, that may well be the case, but the more I ponder, I'm not absolutely certain. I know self assessments can be horribly inaccurate, but I think the outward " anti-authority" in me, masks a bit of under confidence, particularly when it comes to the hands on flying. As an aircraft tradesman, I have all the confidence in the world, no problem flying in anything I've worked on. So far, and I emphasize "so far", my flying is quite conservative. While my wingman is playing down low (legally),you will find me around 1ooo agl min, and keeping over open ground, and tight circuits. Not because of the law, but because it keeps me and my aircarft safe. So far this has served me well.When it come to the law, things change. Sure, I will do what they want to avoid fines/prosecution, but I've been around long enough to know that, a lot of our laws ( not just aviation) are not really about safety, and more about being seen to be doing something about a perceived problem. Ultimately, it is trying to break the laws of physics that will kill you, the laws of man will just cost time and money, and occasionally blind adherence will kill you.

Getting away from design, a few of the things I've learned are:

(1) Try to always have an alternative. The alternative to having an engine, is the ability to land safely. I've had to make the odd precautionary landing due to weather; you would not believe how many wires are out there; they are all over the place. What looks like a good paddock from 5000 feet may be a vertiable spider web when you are committed to it.

(2) Don't fly if ANYTHING is not working as it should; find out why, and fix it. If you take off with a drop on one magneto, for instance, Murphy will leap into action to cause a plug to foul on the remaining mag. Same with a low fuel pressure on one of the fuel pumps, etcetera. People call this the "swiss cheese" principle; having a known unservicability is lining up one set of holes. In WW2 they used to talk of "gremlins". On this heading, the normal form of in-line paper-element fuel filter is an open invitation to Murphy. Little aeroplanes have minimal redundancy; so what IS there, needs to be as good as you can make it. Good does not, in general, equal complicated.

(3) There are three critical factors, apart from airworthiness of the aircraft and the pilot; they are fuel, daylight, and weather. NEVER operate to anything like tight limits on more than one of them at a time (and don't believe the fuel gauge, always dip the tank or fill it to a known visual level).

(4) You normally do not find powerlines above the level of the surrounding hills. You DO find them below this. Sneaking down a valley under the clag is a really good way to discover there really was a powerline where you thought there wasn't one.

(5) If your passengers absolutely MUST get home, drop them off at an airport where they can catch an airline flight.

(6) NEVER put somebody with a camera, in a seat that has a set of controls.

No doubt people can add to this list. Yes, I'd cross Bass Straight in a single-engine aircraft - but it would be an aircraft with sufficient glide performance and with sufficient VFR ceiling, to glide to a landing spot from any point. I was a passenger in a C 172 on a night flight once; 5 hours over outback QLD, mostly covered in trees. It dropped a valve a week later. So a Lycoming is pretty good, but nothing is absolute if you do not have an alternative.

Pick your stainless. Aircraft exhausts should be type 321; weld with 347 filler.

Oh, well, in for a penny . . .

Point 1: There are a surprising number - if you look for them - of people for whom flight instruction is a way of life. They are wholly dedicated to it, and make every effort to improve their competence. I'm not an RAA instructor, but many years ago I was a GFA instructor - and the GFA took (and still takes) instructing very seriously. Back then, most of the senior instructors were ex WW2 pilots; they were all extremely experienced survivors, and bloody good teachers. The best I ever met had learned gliding when Hitler was paying for it, and he had survived 3 years in ME 109s. He was the categorising instructor for NSW, and he checked out ALL the GFA instructors in NSW. Hell of a nice bloke - but nobody could put anything over on him. There were at least a score of people of this calibre in gliding in NSW at that time, and they kept the standards right up, without ruffling anybody's feathers in the process. OK, those people have all gone now, but the principle still applies.

I've found people like Tony Hayes and David Eyre and Trevor Bange in the RAA system in QLD, and there must be others like them. What is needed (if it does not already exist) is an hierarchical structure that allows these people to get together with the less experienced instructors, about once a year, and compare notes. Nobody knows it all; but in a group like that, everybody raises their standards. Easier to organise on a statewide basis than on a national basis.

Point 2: The process of instruction involves a steady transfer of responsibility from the instructor to the student; everybody has an "overload" point at which they "blow a fuse" and in effect stop functioning. The instructor's job is to keep the student's workload sufficiently below the student's overload point that the student can absorb the lesson; and as the student advances, to progressively increase the workload so the students "overload" point is raised. This has to continue to the point of putting the student into unexpected quasi-emergency situations (such as inducing a spin "over the top" from a climbing turn) until the student automatically does the right recovery action, and does not go catatonic. Spin training is very necessary for this reason alone. I've had ab initio students freeze up from simple getting no response to a circuit radio call; I had one bloke who grabbed the canopy release in his panic reaction to a very gentle stall - and another fellow who froze with the wrong rudder applied in a spin recovery (that resulted in a buckled rudder pushrod - but fortunately the Blanik rudder pushrods run in a tunnel, so I was still able to overpower him). A more experienced instructor than I was at that time might have been able to assess that those students were in need of extra-gentle handling. An inexperienced pilot in lieu of a trained instructor would probably have been killed.

Point 3: One of the purposes of instructor training, is to develop and standardise the "instruction patter" - for example, if the instructor tells the student to "flare out" from a landing approach, it generally produces the wrong result and results in the student getting a fright, which is highly counter productive. This is why you will hear the instructor tell the student to check the descent or to level out. Reading the instructor's handbook is usually very enlightening in this regard - tho I've not seen the RAA one.

I don't know where the RAA scene is, in these regards, right now. But it's entirely possible for such an organisation to develop a really competent pilot training system; just find the realy dedicated, experienced instructors, and put them in charge of an annual instructor training meeting.

And DO NOT muck about with the carbie hot-air system - that's a significant certification item and caused a lot of trouble in development. I do not doubt it's troublesome - it was never well engineered by Skyfox - but at least it meets the certification requirement. The manual control of it is mandatory.

I have always considered the LAMEs to be the unsung heroes of our aviation safety; as a CAR 35 engineer I got to know quite a lot of them, and I came to have the utmost respect for them. CASA treats them as criminals and rogues, and is constantly looking for opportunities to prosecute them. This was not always the case, but it is nowadays. Many aircraft owners behave as though the LAMEs were grossly overcharging thieves. That's not my experience; however many aircraft cost more to maintain than they should; and few owners bother to find out why. I'm putting a Blanik glider back in the air, and I'm doing quite a bit of the work myself (I have the necessary maintenance authority). The ASIs and altimeters (there are two of each, it's a tandem-seat trainer) have to be overhauled - they are 3000 ft/turn types, and need to be replaced with sensitive altimeters. That's around $ 900.00; the safety harnesses are in need of re-webbing - that's around $ 450, provided they are acceptable for overhaul. The radio has to go through a shop. The rubber shock-mounts for the instrument panels need replacement - another $106. The control surfaces and flaps needed re-covering - the materials alone cost over $3000.00 - I'm providing the labour - about 200 man hours; I'm enjoying it, but I wouldn't want to do it for a living. Aircraft cost money to maintain. Most people have no idea how much they cost, and they tend to blame the LAMEs - which is simply wrong. Add to that the various fees and charges - RAA fees, insurance, hangarage etc.

The Fokker F-27 that I managed for CSIRO in the 1980s, cost on average roughly $800 per day back then, standing still, just to keep it airworthy. That was about 20,000 Kg of aeroplane. On that basis, a 600 Kg RAA aeroplane might cost about $24 per day, standing still. My PA 28-140 worked out at around $3000 per year (in 1985) just standing still.

Then there's fuel. One compensation of a glider is that it doesn't burn much fuel - unless you put a motor on it so you can go places when the thermals are not popping.

The LAMEs are not the root cause of aircraft maintenance costs. However, they have about the most thankless task I can think of. This is sowing the wind; we will reap the whirlwind in due course.

That's not always an easy question to answer. In this case brand can be a good indicator as the quality iPad accessory brands (Belkin, Griffin, etc) are in cahoots with Apple to have their stuff tested and certified, and they have a reputation to protect. Unfortunately though you are always going to pay a premium for this (e.g., Lone Star are the brand shown previously, and they do several TSO certified 5V adaptor products such as what I have in my plane, but they're expensive).The big boys have been using and charging iPads in the cockpits of their Boeings and Airbuses for a while now (the only restriction is not having them plugged in for takeoff & landing, but you can plug them in on continuous charge in the cockpit for the rest of a 12 hour flight). Sure, these are certified power sockets using the Apple chargers (the quality thing again), but I think it's obvious that they don't consider having an iPad on long term charge connected to an aircraft power supply an inherently risky proposition.

Spoke today to Apple Support about how. "... permanent-magnet alternators regulate the charge by pulse width controllers which chop the alternator output into short pulses - but don't control the maximum voltage of the pulses."Was advised that a cigarette lighter adaptor is ..."fine for occasional charging when necessary, (when charge is under 10%) but not recommended to be a daily practice."

 

Looks like I will only be plugging in iPad and iPhone when they get low.

Fair point. I will admit that I was thinking of equipment rather than batteries, but you're right. Batteries are the exact opposite of what I said. They have a very low internal impedance, and rely on the supply to limit the current.

Only guessing, but I'd be surprised if it drew more than the amp. However, even if it did draw more (say 1.5A to be excessive), then with the supply providing one amp, the internal batteries only have to supply the other half amp, and the iPad will still be running long after your bladder has exploded and you have to be on the ground anyway!

Someone beat me in pointing out CAO 108.56 is now cancelled. You will find all the instrument calibration requirements embedded in an updated CAO 100.5

Thank you.