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aro

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Everything posted by aro

  1. aro
    20 odd years ago when I was training, the procedure was to join crosswind over the departure end of the runway. This has the advantage that if one aircraft joins for 18 and another for 36, they are separated and have time to figure things out before there is a risk of collision. For whatever reason, CASA decided to modify the procedures so you joined midfield (or maybe 2/3 of the way down the runway?) I don't remember whether it was a specific recommendation, but people started referring to "joining midfield crosswind" because it was in a different place to the previous "joining crosswind". I'm pretty sure the overhead join is just another name for what Australia calls midfield crosswind... because you join overhead the field, rather than on downwind etc.
  2. aro
    The one thing that seems to be missed in this thread is how poor the VMC minimum conditions are. If visibility is 5000m you are legal, but you can't see a horizon, you can't see landmarks 3 miles away, you can't see mountains 3 miles away. Even the maximum 10000m the BOM will report is very poor if the visibility is actually 10000m. Legal VMC conditions can in practice be IMC, so you need to be aware and you should probably use much higher minimums than simply what is legal, particularly for visibility.
  3. aro
    Try again - the word you are looking for is "cloud". Visibility is how far away you can see things you don't want to fly into - clouds, mountains etc. Clouds are - well, clouds. If visibility is 5000m you can't even see a cloud until it is closer than 5000m.
  4. aro
    See the column that says Distance from cloud? It says 1500m horizontal, or Clear of cloud at or below 3000 AMSL or 1000 AGL - not 5km.
  5. aro
    Yes I know, I’m just questioning whether you understand it.
  6. aro
    If the 5km applies to distance from cloud, how do you explain the requirements to be 1000m horizontally from cloud above 3000', or clear of could below 3000' / 1000' AGL? Wouldn't they be redundant?
  7. aro
    A 72kWH battery will run a 90kW motor for less than 1 hour. Reduce to 50% power and you can probably claim 1 hour plus reserve. How long will 100kg of avgas run a 120HP engine at 50% power? That's the problem...
  8. aro
    That just means I found enough references to convince me, but not something to quote as a primary source. But the FAA has it: https://www.faa.gov/sites/faa.gov/files/13_phak_ch11.pdf (p 11-8): The service ceiling is the altitude at which the aircraft is unable to climb at a rate greater than 100 feet per minute (fpm). If you're familiar with Cessna 172 performance, 500fpm is obviously wrong. That would give a service ceiling somewhere around 5000'. The actual service ceiling is given as 13500.
  9. aro
    I think that number is for jets. For other aircraft the number is usually 100 fpm I believe.
  10. aro
    Yes, but "level flight" requires AOA changes as the power changes. So yes, the speed changes if you change the AOA to maintain level flight as the power changes. You are talking the practical technique rather than aerodynamics, and you are correct UNLESS you actually want to argue whether AOA or power controls the speed.
  11. aro
    You might disagree, but physics says you can't fly at a different speed at constant G without changing AOA. "Stick forces" are an indication of changing AOA. At cruise it might only be fractions of a degree and too small to call a pitch change, but the AOA is changing. Power is only a measure of energy input. If the AOA stays the same, power causes you to climb. If you change the AOA i.e. with nose down stick force to prevent the climb, speed increases.
  12. aro
    That's technique (how you do it) rather than a description of the effect. The increase in stick forces as you are accelerating is the adjustment to the angle of attack to increase speed rather than climb. When you trim doesn't change what is actually happening.
  13. aro
    The carburettor creates the temperature drop. The drop in pressure across a closed throttle plus the evaporation of the fuel significantly drops the temperature of the air downstream of the carb - by as much as 10, 20 maybe even 30C. So downstream of the carb you have water condensing out of the air, and possibly surface temperatures below freezing. So all you need is moisture in the air (humidity, not visible moisture) - the carb does the rest. https://www.casa.gov.au/sites/default/files/2022-10/carburettor-icing-probability-chart.pdf
  14. aro
    Speed is always controlled by angle of attack (at constant G). Power does not appear in the lift equation. But sometimes e.g. on a precision glide path it is easier to change power first, and then change the AOA gradually to change the speed. This avoids significant changes in flight path. The problem, and what makes this more difficult, is that changing speed also changes drag and therefor power required. So you might need more power adjustments as the speed changes. If you don't have to follow a precision glide path it is easier to set the speed first and then adjust the power. If the speed is not fluctuating, the power required to overcome drag stays the same so you don't end up chasing it. This is more pronounced at slower i.e. landing speeds. In cruise, you set the power and then adjust the trim i.e. angle of attack to give a speed where you are not climbing or descending.
  15. aro
    There's pretty much always moisture in the air in Australia. That's what appears on the outside of a cold drink. If it gets very cold the amount of moisture in the air is significantly reduced.
  16. aro
    No. I wouldn't discourage people from insuring and I applaud your intentions, but that's not what insurance is there for. Public liability insurance is there to protect YOUR assets. The insurance company takes over defending the case. If at all possible, they will pay zero to the injured party. If a payment seems inevitable, they will work to pay them the minimum possible amount. When you took out the policy, you entered a contract to help them pay as little as possible to anyone injured. It doesn't matter who they are or how badly they are injured, you must work with the insurance company to minimize their payout. If they can't show that you were negligent, they get nothing, no matter what they actually need. This isn't a very fair system - many people need help and don't get it, and much of the money is absorbed by insurance companies and lawyers. That's why we have a different system for car crashes - they are common enough that the system couldn't cope with the cases to try to prove negligence, and the majority of people who need help would miss out. So we have a no-fault system where you are automatically covered and you don't have to prove someone (with assets) was negligent.
  17. aro
    It's not exactly news that cars and trucks can be used for terrorist attacks. People have been doing it literally as long as I can remember. Wait till you find out about fiction books. 600+ pages on the details of planning new and inventive attacks...
  18. aro
    Wasn't that the thinking behind the Tomahawk? Flying schools said we want a trainer we can teach spins in, so Piper built one. Then the schools said "Oh! If you stall it it can spin, we don't like that" and didn't buy it.
  19. aro
    The problem with the ASIC is that they couldn't actually deny one to a suspected terrorist without tipping them off that they were being monitored. That would provide a tool they could use to work out which of their members was under suspicion. So more than likely an ASIC would be approved anyway for someone known to be plotting something. A security check where you voluntarily apply and get told the result is fatally compromised for any situation involving secret intelligence. Far more useful are security checks that you don't know are being done and won't find out the results (and I'm sure they occur).
  20. aro
    They don't, and you can't just fly them to another country like you could with a normal aircraft. Same applies to the USA AFAIK, the design standards quoted above do not apply to experimental category aircraft.
  21. aro
    No-one is talking about RAA getting IFR. IFR and CTA are totally different things.
  22. aro
    No-one's saying you don't need training. But you have the same deal with GA pilots flying out of controlled airports into a CTAF. Weird radio calls, no idea how to join a circuit, flying a straight in approach because that is what they would be given by ATC from that position never mind the traffic, downwind landing because there's no ATIS and the wind didn't match the forecast... all sorts of things. The idea that GA pilots fly to a higher standard is just nonsense, based on my observations. GA pilots can be just as rubbish as RAA.
  23. aro
    Austers into Mascot and DC4s are a long time ago. I did my PPL at Essendon so I know a little bit. When was the last time you flew VFR in Class C?
  24. aro
    I think people hugely overstate the difficulty of CTA. Maybe you only flew IFR in CTA? VFR is not the same as IFR. Really, the main thing you need to be able to do are: Fly a heading Fly an altitude Visually navigate and follow a track Talk on the radio and follow instructions. If you make a mistake, ATC are there to help. Will you get in the way of a jet if you make a mistake? No - ATC will keep you well out of their way so that is not possible. If you want to cause problems for jet traffic it is much more likely OCTA under the steps north or south of Melbourne - where the separation from jet traffic could be only 500' vertically - at least theoretically. Or somewhere like Mildura where you have RPT traffic in a normal CTAF. Talk to the people who fly out of Essendon and they will tell you flying into a class G airport is much more difficult because you have to arrange and judge your own separation, without ATC to help you. They hate it.
  25. aro
    Looking at the descriptions, I can't see how it could happen unless the guide track itself wasn't attached to the door properly. It will be interesting to see what they find from examining the door...
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