RFguy

ferrous objects or magnetic field generators (DC carrying wires() influence the local magnetic field, and give it a different shape. In absence of interference, the earth's magnetic field look appears homogonous and without deviation in the local region. Consider the fields around a bar magnet in a bath of iron filings in suspension. In absence of the bar magnet, they will all line themselves up inside the tank identically. the whole tank will be same. If you introduce a tiny bar magnet into the solution, it will introduce the shaped fields and reorientate the particles in the classic bar magnetic shape. The bar magnetic field will vectorially add to the static (earth) field. Pick a 3d spot in the tank. Now, if you rotate the tank 90 degrees, you'll find the point you chose in the tank , the vectors of the earth's field are now 90 deg to the previous influence, and the new resultant vector will be different. If you had two vectors 1< 0 (earth's magnetic field) and 0.707<45 (bar nagnet) , the vector result is 1.58 < 18...... now if we rotate the tank 90 deg CCW so that we have 1< 90 and still 0.707<45 (bar magnet) , the new vector result is 1.58< 71deg . quite different angles ! IE the earths field was at 0 deg to start with. we introduced the magnet to the tank . now it reads 18 degrees. OK, so if you 'simply' subtract 18 from the compass, you get 0 deg OK, but rotate the tank and now the compass reads 71 degrees. if you are still subtracting 18 degrees, now the compass reads (71-18 = 53deg) instead of what it should read (=90 because you rotated the tank and compass 90) . so single point corrections do not work.

It's not the calibration of the magnetometer that is required. Just like a (wet) compass doesnt need calibration- It is COMPENSATION that is required - due to iron, electrical currents, ferrous metal etc. A wet comipass and solid state magnetometer are affected precisely the same way.

I think the only thing that will come out of this in wreckage is whether the rocket in the BRS got triggered, or not. Air services might also have access to might higher time resolution data than presented on flightradar / flightaware.

mmmm. I was involved in the compass swinging for my GA plane a couple of weeks ago, 8 points, couple of times, all within 2 deg, generally 1, there are compensation screws for this to pull it in. Was done on the grass region since pipes, reo etc are all trouble. however! The magnetometer devices in the EFIS etc can be compensated / calibrated with a curve fit, or an interpolated look up table , pretty damn well. However they do need at least 8 points to be on the money if they are to work in any aircraft. And they'll still be sensitive to current flowing in wires in the instrument panel. Most certified EFIS systems required 12 points, which ensures they get plenty of datapoints. The mags in most of the EFIS both internal and external magnetometers are 3D, ((three magnetometers XYZ) so they can work in any orientation. Skippy, if your EFIS only requires 4 points for cal, then the performance is likely bollocks and wouldn't meet a Part91 certified aircraft requirement. But probably, in these days of GPS, PLENTY good enough en-route nav IF it is NOT your primary heading means.

I always get my info from NAIPS directly. Why - ?- because oz runways (android , anyway) sometimes doesn't show updates. It absolutely cannot be relied upon... They are aware of this and are fixing it at the moment. From a software developer perspective, the sorts of bugs I see, means it is not to be trusted. Anyway, it is a very sad outcome for an aircraft with a parachute.

any idea how to access the GAF and NOTAM archives ? You dont depart canberra without talking to ATC on several occassions , would they have had something to say ?

good catch that Chris on the 3600' decent, --but given the reported speed was a long way below the Va, a sudden and extreme control input would only cause a stall. The weak point in the data we have here is that 1) we only have ground speed, 2) The data is sparse in the time domain, relative the the rate of the events. Maybe he was flying 140 indicated and only 110 ish ground.

Hi Mark, I would think unlikely to be structural failure, at least not the first cause, Va is 133 kts and Vchute is 133 kts. Maybe icingand or flight into IMC, then LOC, and too fast for the chute to be pulled. It was very moist at altitude in that region. yesterday, there were thick and dark cumulus allover that region. But given 3 kids lost their lives in an aircraft that should have been very safe, I am hesitant to speculate much further. We'll need to read about it.... As a parent I can only just imagine what the nightmare must be for others....\ Coming back- RAAUS go on about 'flying is so safe , a pilot in everyhouse' which I think is bollocks, flying is inherently hazardous.

https://www.flightaware.com/live/flight/VHMSF/history/20231006/0330Z/YSCB/YARM/tracklog Many permutations and combinations : Pilot incapacitation ? Flight into IMC and rated / IMC current ? (they all have autopilots) In flight fire ? Parachute not successfully deployed (too fast?) Structural breakup (flying over Va in severe turb) ? Va is 133 kts for at least one SR22 I POHed. at 3400 lbs. That's ~ 127kts at my estimated weight. Stall clean is about 70 kts. autopilot disengages in severe turb.... so if you are in IMC AND severe turbulence, that's a non autopilot combo. https://jasonblair.net/wp-content/uploads/2015/06/Cirrus-SR22-POH.pdf

I think MGL is always a good option, they do listen to their customers, also. Maybe can take a look but we're along way from that yet, lots of things still to check. My guess is vibration related. Oh, BTW though WHAT is the 12V bus voltage at 1000RPM, 1500 , 2000, and 2300RPM ???? I've seen a regulator putting out excessive voltages causing voltage spike protectors start to act and putting lots of noise on the 12V...

Nice airport, good tiedown points (lots of them), nice aero club people. Did my usual 120KTAS each way@ 31.5 lph.... Rex was changing a turbine in a saab in the hot sun.....

The only reason I would be hesitant of that size is that you want to make sure it is not being SWITCHED IN. IE it's always across the bbattery and NOT being switched by a contactor . Why? Because a capacitor that size will be a infinite current sink when power is applied- this will tend to lessen the lifespace of any relay contacts or switching contacts. IE a bad idea. Also if there is a fault condition, the capacitor will be ablwe to supply zillions of amps (briefly) . So, suggest avoid using it. If there is alternator noise, that will be some different problem. Some instruments are suceptible to noise, and this should have their power supply LC line filter. You WONT get static like being mentioned here for any likely Jab reason . glen

and if you fly with a Jabiru engine , you are absolutely completely nuts flying without CHT/EGT - a failure will be just around the corner....

Unless you have a sick Alternator Regulator, I dont think it should need the capacitor. Well, I had a colleague the other week and was IDENTICAL symptoms- and it was the connector.... I'd be looking there. TX was fine. Loosening the screws can tell you if you have some sort of microphonic in the radio. BTW when you say "It's a screw in antenna. Antenna is in the tail fin." - Jabiru factory dipole antennas in the tail are not screw on antennas- what are you referring to ?

So, improved technique on the weekend's trip to Broken Hill. Didnt pee on myself. Pee into bottle, then decant into larger master bottle. Although at BH, I needed a drink on the ground and took a swig from the wrong bottle. wont do that again. I hadnt decanted the 2nd pee. from in-situ to master bottle. To prevent that , ont he return I immediately decanted the in-situ bottle.

right, back from my latest weekend YBHI adventure. Antenna ground plane need not be earthed. Since I have a Jabiru and I 'wrote the book on radio' :, please answer the following : 0) Check the connector on the antenna for tightness (BNC bayonet locked) AND what sort of connector ??? - recently I found someone has a right angle adaptor between the radio and the antenna plug- this right angle adaptor wasnt the best and caused reception breakup > 2000 RPM ! (bad connection) . Remove adaptor ! If you need right angle- use with a right angle plug , no adaptor 1) Which antenna is this radio connected to- the antenna in the tail, or the antenna before the rear bulkhead ? 2) To your knowledge , are your transmissions affected ? 3) Have you tested what the VSWR is of the antenna ? 4) Can you physically vibration decoupler the radio from the panel- just loosen the mounting sc rews a couple of turns - does the problem still happen ? that's a start.

so, back to Broken hill this weekend. armed with a bigger bottle. Seems I was very lucky last time to have a tail wind both directions (east to west, west to east). I see now , there's about a 2 day window in 7 of east to west winds. Quite interesting what goes on at different altitudes, at least in the models. al least coming back, I will have 30 kts behind me...maybe more . that will make up for the 10-15 kts headwind outbound. 105k indicated will be just that in ground....

hey what happened to my thread

be sure to remove the varnish off any (rotating) shafts, also. replacing o rings etc, one can forget cleaning the things that run through them .

some engines are good for no-lead, some are not. many have had no-lead suitable seats and guides fitted during overhauls in their 50 year life span.....

It is a good point about water freezing in the fuel lines, Nev. Fortunately, the Piper has good fuel sumps and I've never seen any water in them ever. (never say never ) . It's certainly always below 0 up there. Good point also about wing skins being cold. If I descended through a humid region, or cloud, that's something to consider. I still affirm for long pt to pt flying , flying low is TAS on the table. (FL125 is 123 kts TAS for 100 knots indicated which I can do) Interesting though what happens with the east west winds up there, going west, almost always better being down at say 8500 or 6500 with the headwinds. 8500 is a reasonable compromise. up high, bumps are less, radio coverage is better and options are better for engine trouble (unless u have a fire...) glen (PS: left tank always AVGAS and used for TO and landings, right tank ULP98 when available outbound)

Thinking about this, so many unknowns what is the existing intercom type and how has it been wired to the radio ?

Mike are you sure you just didnt leave it in the seat back pocket?

I wonder if a pre-built / wired harness is something that should be considered. there really isnt much to it. Otherwise labour costs in plane are not insignificant. Shajen, you can ground run the jabiru, just watch the CHTs. Don't let them get over 150C on ground . If the idle is set correctly, there is no problem ground running most Jabirus, but it wont charge the battery at that RPM. Do you have CHTs on all cylinders? If not, forget flying a Jabiru until you do.....

using the internal trig two place intercom ??? wired up the headset wiring correctly? not using shorting jacks ? "radio guys" ALWAYS sit in the plane with them running , up to full RPM and see how it goes... OK overall sounds mainly like a connection problem to the headsets, or some issue with the way the headsets are wired Please post a diagram of how it was wired in the aircraft IE as built. If you do not get this, do not pay the radio guy. glen