poteroo

Thread Resurrection Thought it timely to talk about turbulence and managing its' effect on airframes after the 2 recent Cessna 210 fatal accidents - one near Darwin and the most recent near Albany WA. It would appear from the reports to date that both aircraft broke up in flight. The Darwin accident involved a strutless C210 which was negotiating its' way around significant thunderstorms. There is a possibility that it encountered extreme turbulence in normal cruise - as we don't know whether it was operating at reduced speed or not. The ATSB findings may determine whether there were other contributing factors, eg making a turn which increased wing loading, or had flaps extended at close to the book Va, and others. It was also apparently lightly loaded - a factor which reduces Va, and increases risk in rough air. The Albany accident, (a mid 60's C210 with struts), occurred in clear skies with no known meteorological influences. It seems unlikely that this accident was due to any operational factor as the pilot was a highly experienced aggie and would be all too aware of airframe limitations. The loud 'bang' heard by the only witness, (to date), before he observed the aircraft spiralling almost vertically, and the 4 hectare spread of debris, - would appear to point to some unknown catastrophic event in cruise. The fact of there being no recorded Mayday would indicate the event was sudden in the extreme. All pilots need to heed the airframe limits on their aircraft. Read the POH - understand what Va is, what flap does to airframe limits, what turning does to airframe limits, and more. With summer so close - please keep away from storms, slow down when it gets rough, and avoid coarse control inputs. Fly early AM and avoid the rough stuff. If you are flying a very much older airframe - be aware that it could have been stressed many times in the past by unknowing or caring pilots - treat it with care and respect. safe flying and happy days,

Enough! Enough! If you couldn't demonstrate enough nous to look up both the correct spelling and meaning of the word debacle: then you should be more restrained in your criticism of RAAus and the AA organisers. What a petty, spiteful and ungrateful thread this is! Ian, you should lock it asap. (thread is being edited...mod)

Back in the 60s when there were lots more firearms about the country - there was an unusual story doing the rounds at Archerfield of a 'Cessna' being brought into a maintenance facility with a bullet hole in the tailplane. Not unusual you might say, given that many outback Cessnas were flown 'door off' while a firearm was being employed in 'culling' duties over the station. But this one was said to be very unusual - the bullet entered from the top and emerged from the lower surface! The pilot was said to have been 'beating up' a farm in some very hilly country down in the QLD/NSW border ranges, where it's not impossible to fly past lower than a house! Quite a good story - but completely unauthenticated. happy days,

I've found that The AOPA Airfield Directory, or the WA Country Airport Directory give about as much info as is available. Another option is to checkout listings for flying schools and for aero clubs. They may not operate a public access bowser - but may be able to help out in a tight situation. With Local Government - ask for the Works foreman - he usually knows what's happening at the coal face. I would rarely go anywhere these days without an empty 20L jerrycan stowed in the baggage area as it does give you an option of landing and obtaining a measurable quantity of fuel from wherever you can land close to a town.... with a taxi service that is amenable to carrying fuel. happy days,

I'd agree with the popularity of RV's, but lets remember that their usual MTOW lies between 750 and 800 kg. That's a very good reason that we should be looking at 800 kg instead of 750 kg - if we hope to include the RV series in RAAus.There actually isn't an 'upper' limit under EXPERIMENTAL category because each aircraft is a custom build and is then test flown through 25/40 hrs and a set of flight numbers are generated from those tests. If the builder/test-pilot is doing their job responsibly, every RV will have slightly different 'numbers'. My own RV9A has 795kg MTOW and stalls @ 44kts. We also need to recognise that their popularity, with 160-200 HP 'Lycoming' engines, has much to do with cheaper fuel over there. Despite there being a 'low' compression engine being available, (with lower HP), do many of these get fitted? I'm told - not many. Unless CASA takeover all of RAAus 'operations' - then it couldn't happen because RAAus doesn't have the legal powers to conduct much in the way of 'compliance & enforcement'. Only CASA FOI's have such power, and they would have to be directed to become active within the RAAus pilot group. In any case, the 'big stick' approach hasn't worked in the past. An improved training syllabus , with more recurrent training requirements, is probably a more effective approach. happy days,

Couldn't agree more. 1500kgs was always going to prove 'a bridge too far'. The horses have been frightened with this obvious ambit claim. 800kgs would have been smarter, insofar as allowing ex GA types into RAAus. It would have included all the C150/152 types with 757mtow, and the majority of VANS RV's, (my 9A is 795kgs mtow). It would however, create a uniquely Aussie category of aircraft......but, who's counting? We already have several CASA inspired unique Aussie rules. Insofar as CTA is concerned - that's quite a different argument for CASA. It is really about safety, rather than convenience, and the argument should have strictly pursued that line. Learning CTA rules and doing an endorsement is well within the capabilities of an RPC, and aircraft can be brought up to 'CTA' standard by the application of $$$. Running with safety alone should have been an easy 'sell' to CASA, and I am amazed that RAAus couldn't achieve it. happy days,

Spot on! I strongly recommend buying or building a type that is popular and there are local examples. 'Orphans' can prove very costly! If it's an RV - there is a lot of knowledge about: in building tips and test flying tips too. happy days

Yes, and mostly are avoidable if the pilot has been trained to fly the aircraft in balance at all times. I encounter a disturbingly high number of pilots who skid the aircraft during left turns, (as onto final). This is a surefire way to spin 'under' and at 500ft or lower = no recovery likely. As you can guess, I'm a proponent of lots of 'co-ordinated' flight practice for students. If you can't fly 'in balance' - then it's difficult to learn how to fly intentionally 'out-of-balance' - as in slipping for height loss, and in crosswind ops. happy days,

Va for a C172 varies with weight - as does Vs. The range is from approx. 103kts @ full gross wt down to 88kts @ wt with jockey + minimum fuel. Quite surprising. happy days,

It was an inspired decision by CASA to name the old GFPT, (aka RPPL), the RPL. It completely muddied-the-waters in the 'recreational aviation' sector, and validated a public perception that a licence trumps a certificate. The fact that you must hold a 'real' (CASA) medical, in order to hold a 'real' pilot qualification, (a licence), has undermined the authority of all RAAO's, and RAAus is now in an invidious position. What Machiavellian policy is behind it is beyond mere pilots to understand: probably quite clear in Canberra?

Innt To really connect all the terms, I have read Turbulence-The Aeronautical Forecasters Handbook, from BoM. I have a digital copy for anyone who is into this stuff - but beware - it's heavy going in places. From this book, on p5 - Table 1 connects IAS variation to vertical gust fps to G load to aircraft reaction: Intensity IAS variation vertical speed G load aircraft reaction cockpit reaction light 5-14 kts 5-19 fps 0.15 - 0.49G slight little moderate 15-24 20-35 0.50 - 0.99 rapid bumps,jolts strain on belts severe >25 36-49 1.0 - 1.99 large changes, objects off floor, loss of ctrl forced into belts. extreme >25 >50 >2 out of control - damage likely-injury likely I recommend this book to interested pilots. Yes, the high altitude stuff in regards to VNE and TAS isn't likely to be of great relevance in Australia because we are usually well under 10,000 ft - whereas in the western states of the US it's not unusual for RV owners to cross the Rockies at 13,000 - 14,000 ft. Many RV's have O2 and many RVs have 180HP and above engines. They also fly at 75% power everywhere. The article on HP choices for RV9 series RVs is interesting. I 'disobeyed' VANS by fitting a Superior IO-360 to mine, and the dyno tests showed 190HP. (it has both injection plus EI on one mag). Now, on reading his article you'll note that he is talking about 180 HP engines being flown at 75% power, (and because most US aircraft are CSU fitted as well - his story includes this performance enhancer as well). But, I believe VANS misses the point here. He is not recognising that Va is calculated on the published positive load factor,(3.8), and the actual stalling speed clean, (Vs). With a Vs = 49KIAS in my 9A, and then x that by the sq.rt. of 3.8 (=1.95), I calculate a Va of 96KIAS. This quite a lot lower than the 106KIAS that is evident in the V-n diagram shown in the VANS article.This has nothing to do with HP per se. But it does have a deal of relevance for flying an RV9A in Australia. For a start, we don't usually fly at 75% power because avgas is much more expensive in Australia, and it's often a long way between refuelling stops. So, the average Aussie 9a is flown at lower IAS than in the US. When they start quoting 156KIAS, and we are more often looking at 130 KIAS at 8500' - there is quite a difference. And, from talking with other 9A owners with higher HP engines, I find that most use them mostly to enhance rate-of-climb performance - not trying for higher en route cruise speeds. Most seem to target a particular KTAS for cruise, eg 140,145,150, and then set up power and lean to achieve. So, the probability of sustaining damage due en route turbulence is lower here than in the US scene. If you look at the numbers published by VANS - you'll see a Va of 112 given. It's shown as a blue line on their analog ASI gages. How did they derive this?? It's a long way above the Va that I derive for my 9A, and mine is based on the real life stalling numbers as I measured them using real life weights. (Sure, I'm using IAS instead of CAS, but the differences won't be much and my ASI was found to be quite accurate on test). Why would this be? Whose numbers do I believe? Mine of course - because they are the more conservative. Using my numbers allows me to traverse some rougher air than I might otherwise tackle, allowing for the skirting of stormy areas and frontal and trough lines at my <100KIAS self imposed limits. I realise that these examples using RV's are some way from the average RAAus aircraft doing 90-100KTAS - though the principles remain the same. Just because you cruise at 85KIAS doesn't mean that you can ignore your operation in turbulent air. Have a look at your Vs at usual weights, then x by 1.95, and you have your Va. My guess is that many of you are in for an awakening - you'll end up with numbers in the 60-70KIAS range and that's not surprising because you can't have low Vs and high Va unless the aircraft has been built stronger than + 3.8G. happy days,

Our training area ends along the south side of the Stirling ranges - 27nm from the airport. Another good obvious geographical feature is Mt Manypeaks some 23nm east and Denmark town the same west. So, the advice to pilots here is stay inside those locations. Given that they are often without GPS, it seems practical and sensible and I have never had a pilot arguing the toss over it. But, some pilots obviously want to split hairs. One RPPL from Perth is reported to have been pinged in Darwin when he made a meal of getting a clearance! Now that's a lot of consecutive 25nm sectors! happy days,

If you are flying an aircraft with a 'G' meter, (and most EFIS units have these as standard), then the following applies to Turbulence: Very Low: - < 0.05G - light pitch, yaw & roll Low: - 0.05 - 0.2G - choppy, cobblestone effect Moderate: 0.2 - 0.5G - uncomfortable bumpiness Severe: 0.5 - 1.5G -abrupt bumps, difficult handling Very severe: > 1.5G - aircraft thrown about, near loss of control. But, when you consider just the vertical gusts, (as do the engineers with their Vn diagrams), then the following applies: Weak: 5-10 m/sec Moderate: 10-15 m/sec Strong: 15-25 m/sec Severe: >25 m/sec I am lucky enough to have Dynon D-180 EFIS/EMS in both my RV and Brumby so can measure the amount of turbulence on any one flight. It is instructive for both myself and student because it allows for some level of 'quantification' of the conditions that we've just experienced. I have always planned to advise my LAME of any severe experiences that we have in the aircraft and that would be backed up by knowing the 'G' numbers. Standalone G - meters are not that expensive anyway, and anyone who flys close to ranges and in the hotter parts of Australia should consider one. happy days,

Very sensible: and it's because the calculation of Va is dependant on the square root of the load factor x the clean stall speed. The LF of most RAAus and GA aircraft would be 3.8 nil flap......BUT.......only half that with flaps extended! With a lower Vs1 than Vs, and a LF only half that for unflapped flight - the sensible thing is to use nil flap if it is exceedingly rough in the approach. The Auster is very tough and these calculations may be less applicable to it because we really don't know just what standards they were originally built to handle. Notwithstanding, I would be getting well under Vno of 95 whenever it became seriously rough. If not for the structural failure reasons, rather for the reason of maintaining controllability without losing it. A 'target' IAS of half way between your Vno and Vs would place you in a safer spot I'd think. happy days,

I think it probably does apply. You would need to have it 'signed' into your logbook though, and the instructor would themselves need to have been found competent to use GPS under 61.385. Then, the instructors' instructor would need to have been signed off under 61.385. Then, that instructor would..............ad nauseum.

There is another thread running in the European section, but I believe that this is such an important subject that it should be re-opened here in Training. As an instructor who has conducted many, many Flight Reviews over many years, I can confidently state that the knowledge most pilots hold about 'safe speeds' in turbulence is frighteningly low. I've had pilots tell me that anything under Vne is fine. Others have stated that as long as your needle is below the yellow arc on the ASI - you're fine. Very, very few understand the relationship to gross weight and stalling speed of the aircraft. Very few recognise moderate turbulence when they feel it. It's no wonder that aircraft breakup in flight! Aircraft which spend more time at low altitudes are known to suffer greater stresses in the airframe. Low level activities such as mustering, ag, and survey create lots more need for airframe inspections. I've heard some truly terrifying stories from maintainers about tailplanes virtually 'flapping' after thousands of hours mustering. I've had some real frights with turbulence. After several, my legs barely supported me after landing! Australia might have an absence of high mountains, but it consistently has ambient temperatures 15-25 degrees above Standard - and that means lots of thermal activity. Diurnal heating should always be in mind when selecting altitudes - sometimes a little more headwind is better than an uncomfortable rough ride. So, to start with - who knows the load factor limits of their aircraft, both clean & flapped? Who uses a G-meter to keep an eye on things? Who knows the formula to calculate Va. Is Va close enough to use as a proxy for turbulence penetration? Who adjust their cruise speed to suit the turbulence experienced? I'm seriously interested - lets talk.

I've done the trip Laverton (WA) to Yulara (Ayres Rock) a few times. You can fly direct over double tiger country, or go via Warburton Range and be over a frequently used road for most of the trip. The difference is about 15 minutes at 120 kts - or your life perhaps. I'm also reminded of my yellow streak when looking at my logbook entries for crossing Torres Strait. The 4 ferry flights I did from PNG to Aus were via every island between Saibai and Horn Is, (and that was in the days before most of them had strips). happy days,

Agree. Where it really is tiger country - the circling climb to cruising level is prudent. Out in the real inland regions, a circling climb with an overhead departure is a smart way to ensure you depart 'on track', and with an engine that has already run for several minutes more under power without any disturbing noises or indications. happy days,

IMHO - you appear to have been. But, you're talking a full PPL, with Class D and C CTA privileges - bound to cost more than RPL, which after all is the old 'country PPL'. Because we run both schools 'back-to-back' here, and both CFI's are GA Grade 1's with >10k TT, and both instruct in both schools, I think we have a reasonable transfer of pilots. In the RAAus school we actually do IF time in the EFIS equipped Brumby, and in the cross-country endo we fly the same routes/times as do the RPLs in the c172. Our RPCs appear to take only 5-8 hrs of C172 time to complete their conversion to RPL. The 172 is a very easy aircraft to fly after you've been learning in an RAAus type with the same yoke & throttle layout. happy days,

Clinton, Are you flying a C182 or is it a C172XP with CSU? You've given both so far. These heavier Cessnas tend to be very forward CG when flown only 2 up and no pax or baggage. I've done several thou hrs in them and many, many endorsements. My best bet is loading it up by adding at least 20-40kg in the baggage compartment: which brings the CG aft and gives you more trim range. With that loading, you will be able to land it on the mainwheels and avoid the near 'wheelbarrow' landings that are common with these types flown for endorsing. Get out your load chart and load it up legally. I've managed 26 kts xwc in the 182 but that was really trying! Have found that 20-30 deg flap is more than enough. 10 deg for t/o on hard surface is necessary, especially loaded to gross. If you find that the x/w is such that you run out of rudder, then perhaps use more flap plus carry more power to improve rudder command. I found that the C182 was more likely to be 'limiting' in aileron command than rudder, and all you can do about that is fly the approach and roundout slightly faster. There comes a time when you just have to admit defeat and land the aircraft more into wind - whether you do this by orienting yourself 10-20-30 deg 'accross' the strip, or use the grass flight strip on the diagonal, or, (when really desperate), the taxiways look good. Whatever it takes! happy days,

After 137 posts - we are arguing about how to teach a level turn??? In respect of the thread title ' Shiny,New RAAus'................. On my required info list is for RAAus management to detail exactly what RAAus does,(and the $ cost), to comply with CASA. Then I'd like to know what RAAus have to spend, over and above what CASA provide as a grant. I believe that we, (RAAus that is), should not be doing any extra work (for) CASA than we are paid for. I choke at the thought of doing CASA's work for them, at our cost! Do we believe that our new Board is looking at the RAAus workload,(on behalf of CASA), and is working toward having CASA pay a fair and reasonable fee for the service that RAAus provide?

One of my personal flying rules is that the best precautionary landing ...... is a diversion to a safe strip. I still hold to that after 54 years in the saddle. After 4.5 hrs flying on my last long distance ferry flight - I heard the YABA AWIS calling below VMC conditions. Diverted to the closest, (all weather), strip 40nm to the NE and landed. Made a few phone calls. Waited for AWIS wx to improve. Chewed on some dried fruit & nuts in my emergency supplies. Then set off home after having a nice, safe, pit stop where both the aircraft and myself were not at risk. Yes, I probably could have pushed on into some marginal wx, but after so long in flight, and at my age, I recognise that I'm getting tired, and that isn't good for negotiating seriously bad wx. A diversion due weather is usually something that you can see approaching. So, it makes sense to pick a point on, or off, your track - over which you divert. This gives you a minute or 2 to roughly estimate the new track, and distance to run, before you make the turn and mark the time. happy days,

Agree that this was one of their causal factors. To minimise the radius of turn - the aircraft needs to be flown at the lowest possible IAS. They probably needed a 45 deg aob turn to avoid CFIT, and to do that from 50 kts would require a lot of power to accelerate it. My guesstimate is that it had a Vs of about 40-45 kts. So, they could not roll into a 45 turn until reaching at least 1.21 Vs (= 55 kts) Operating at less than 1.2 Vs requires a heap of power and acceleration as the aircraft is rolled into the turn - otherwise the aircraft will be at risk of stalling in the turn. Making entries into steep turns from low level requires a deal of instruction and lots of supervised practice. Even more important where the aircraft is already flying at only 1.3 - 1.4 Vs for operational reasons. I find it difficult to comprehend pilots flying so low, and slow, when in proximity to hills??

ANSWER = plenty, and there'll be more. But, I believe there's more to this than just running out of room in a dead end valley. It's likely that they were unable to utilise all of the space available, because, when they realised that it was the 'wrong' inlet - they were not flying close to the shoreline on the right hand side. In this case, they increased power aggressively and began a turn to the left. It's likely they might have made it had they been able to use all of the available distance from one shoreline to the other. That's why LL, (and mountain), pilots are trained to hug one side or the other to maximise 'room' in event of a reversal being required. The other problem these unfortunate pilots had was that in flying low over water, they could not allow the nose to drop into the turn so as to shorten up the space needed. In a valley, you can always allow the nose to drop into the turn because you are turning out over the lowest land in the valley centre. In another forum there was a lot of comment on the fact that this company promoted the A5 using several U-tube vids involving a lot of low level flying. It seems that they may not have followed their LL training principles in the heat-of-the-moment manoeuvring on this mission. I'd assume they were in fact trained to do this sort of flying? Hard enough being a test & demo pilot without adding to your risk by flying low as well. So needless.

Can I suggest that you read 166 for a start. Then, use the search function on here and read the past threads and postings on the subject. Then - go over to pprune.org and search for the huge thread there on this very subject. You'll find that CASA have, (for whatever reason), written 166 in a form that allows for quite a deal of interpretation. The primary requirement is that you maintain safe separation from other aircraft and terrain whilst operating 'near' any airport/airstrip. btw, you cannot assume anything in aviation. happy days.