Dieselten

The device is called the "Cooper Vane" and prevents the rear air-stair being opened in flight. Wikipedia has a short article on it, with an illustration of the vane itself.

D. B. Cooper is presumed to have died, either on exiting the aircraft, in freefall or after landing (assuming his parachute actually functioned, which is not necessarily a given) and his body has never been found. Some partially decayed banknotes from the ransom were found in a swamp. The FBI case is still open but unless the remains of D. B. Cooper are found, a full resolution is unlikely.

Microair rev P and Q radios now very acceptable units. Go well with the Lynx intercom, also Comunica make an intercom that works with it. The INtercom is equally as important as the radio. Make sure the antenna is also properly installed and correctly matched to the feedline.

ASIC very useful as ID when checking in for commercial flights. I usually produce mine and request an emergency exit window-seat (more legroom). Usually get it. Airport workers can obtain discounts on food and beverage purchases in the food halls. You have to eat a hell of a lot of airport food to recover the cost of your ASIC, and you'd probably die from malnutrition in the process! I also usually leave mine uppermost in the tray at security and walk through the metal-detectors as if I owned the whole damn airport. (I have paid enough tax to own at least part of it!)

On those occasions I have inadvertantly left it on going through security I have not been "sniffed" for explosives. On those occasions when I have remembered to take it off I have been 'sniffed" four times - by people who admit to knowing nothing about explosives, because I make a point of asking them.

As it happens, I handle single-based (nitroglycerine) and double-based (nitroglycerine & nitrocellulose) propellants when reloading for rifle and shotgun cartridges so I do know something about explosives, and also where to look for traces, such as in the turn-ups of trousers, inside jacket-pockets etc where dust collects over time. This dust is a complete history of where the clothes - and the wearer - have been. BTW, these techniques are not new, the Gestapo were using this in WW2...our airport explosives sniffers are inadequately trained for their task, IMNSHO.

The ASIC was a knee-jerk reaction by a bunch of jerks to a series of hypothetical threats to the security of air-travellers. If the authorities were serious about airport security, they'd learn how to do it from the Israelis. But the ASIC makes the travelling public feel that something is being done, and that's all that really matters. The shadow, not the substance.

Silva 70 UN.

According to my local avionics supplier, and the Garmin website, the Garmin 495/496 aviation GPS is now discontinued. If you want one, I'd strongly urge you not to delay your intended acquisition.

IMO replacing this very useful aviation GPS in the Garmin product line will be a hard act - the Aera 550 may be the intended replacement, but it fails to impress. I am hard to please, but if it has a coil-type loudspeaker in it (as the 500 does), don't mount it in a panel with a compass nearby!

The 695 is not a replacement ...bigger, more expensive.

Vale the 495 - a superb GPS.

Pilot or not, it' still gonna land - badly!

F/A18-F onto a carrier with no hook, 2 failing engines and an unservicable crash-barrier?

Definition of a journalist: someone who is good for 2 minutes on any subject under the sun.

Alternative definitions: Journalist - a failed author. Editor - a failed journalist.

Engine now at Jabiru's engine shop. Waiting for results of tear-down. May I respectfully suggest anyone who experiences such a failure please return the engine to Jabiru...only by examining lots of such cases will their technicians be able to isolate the cause(s) and come up with a fix. We all want these engines to make their 1000hr Top End times.

Having shown the close-up photos of the broken through-bolt in-situ to several learned and experienced people associated with steel-making and structural engineering (in plentiful supply in my location), the verdict is a unanimous one - FATIGUE.

The question is why did a pair of through-bolts let go at 675 hours when they are supposed to do 1000 hours before being worked on as part of the top-end overhaul? If we had been experimenting with this engine and making adjustments to it then I could perhaps understand. But this engine was maintained by the book and "a good runner" in every respect with never a hint of trouble, no high temps or low pressures at all. In short, this engine ran perfectly until a sudden and inexplicable failure.

Trying to torque-check these bolts, especially on the underside of the engine, is not easy. No special tool seems to exist (such as the cylinder base-nut wrenches for Lycomings and Continentals), and it appears we are left to take it on faith they will not loosen in 1000 hours. In the absence of any signs of crankcase fretting, one has to assume they were tight until the moment of failure. Either that or there is an issue with metallurgy, design, assembly or all three.

So I am at the head-scratching phase of the investigation. Meanwhile I have an AOG, an engine somewhere between here and Bundaberg (and hopefully not under three feet of mud) and no seeming solution in sight except the expense of another engine.

I had expected better.

Another form of noise, usually manifest as a "squealing" sound behind the tramsmitted audio, is RF feedback getting into the audio circuits in either the radio or the intercom - or both.

The cure is to get the antenna as far away from the radio and intercom units and their associated wiring as possible. Add ferrites to taste. Filter capacitors across the main electrical buss, even inline chokes if necessary. Noise can and will get in wherever it can. Tracking down the sources and fixing it can be a time-consuming task.

Interestingly, the inner surfaces appear to be bereft of an any "passivation" measures such as alodyning or anodising. My Bolly-prop hub appears to be alodyned externally and it is fading, but no signs of cracking. It currently has just 290 hours on it. Could be a good time for a disassemble, inspect, possibly some passivation internally, re-assemble, re-pitch and balance. These hubs are prone to water-ingress during washing etc due to their design.

My first 582 went 762 hours and still ran well when it went for a rebuild due to a failing alternator. Second one siezed on takeoff at about 550 hours. Replaced it, flew 13 hours on it and the a/c has since been sold.

Properly maintained and regularly run 582 blue-head engines should run 500-600 hours trouble-free. Most schools are moving away from 2-stroke powerplants these days since the 912-engned trikes have been available. For 3-axis the 2-stroke is also on the wane. It's hard to argue against the reliability and low-maintenance of the Rotax 912. The downside is the high initial purchase-cost.

You end up paying for engines one way or another - either through ongoing maintenance of a relatively cheap powerplant, or in the initial purchase-price for a low-maintenance high-reliability powerplant.

Hi Vev,

Re your questions:-

The barrels were never removed on this engine, nor were any studs replaced. There is nothing in the Jabiru maintenance schedule about torque-checking the through-bolts so they were never checked except visual checks for the Torque-seal paint and oil-seepage at the cylinder-crankcase junction on every daily inspection. No signs of oil-seepage were observed at the cylinder where the bolts failed earlier that morning. (Today, just for curiosity, I took a 7/16" crows-foot wrench, my Sidchrome torque-wrench, and tried to check the other through-bolts at 26ft-lbs. The wrench slipped neatly off the first nut, causing me to leave a fairly significant DNA sample by way of a scraping of my epidermis on the fins of the No. 1 cylinder. The blood-trail led from the aircraft, across the apron to the hangar and the First-Aid kit. With a couple of large dressings now applied to my wounds, for some odd reason I have ceased to have much further interest in checking the through-bolts on a dead engine. The only good thing that emerged from this is I didn't step in fresh dog-turd on my way to the first-aid kit!)

Getting back to thge narrative, the heads were overhauled at 500 hours based on anecdotal evidence from other Jabiru users at the airport. They had their 2200 engine heads off at approx 250 hours and saw evidence of exhaust-valve pitting, and they strongly advised I do the heads at 500 hours. Their engines were similar vintage to mine but with fewer hours.

This proved to be sound advice because the glacier bushes were transferring metal to the rocker-rods, and one exhaust valve was starting to cut away slightly. The inlet valves were re-cut, glacier bushes replaced, new rocker-rods fitted, new exhaust valves fitted, top end decarbonised and heads lightly and carefully lapped back to their respective cylinders. Cost in parts was very reasonable and the a/c was off-hire for only a couple of days.

No EGT is fitted to this aircraft. The oil temperatures and pressures, and CHT, at time of failure were all normal, and the failure mode was instantaneous. There had been no abnormal behaviour or indications throughout the flight up to the time of failure.

Hope this helps.

Another failed set of through-bolts to report....

On 23rd December 2010 Jabiru engine 2200B no 102 had two through-bolts shear whilst on descent at 2800RPM, carb-heat on and fuel-boost on (detonation? I don't think so!...carby-heat makes the mixture richer, remember). This engine had 675.8 hours at time of failure, the heads were overhauled at 500 hours. Very disappointed. This mill has been maintained by-the-book (or better) by a Level 2/LAME.

Managed to reduce power to 1800 RPM and nursed the dying engine back to the runway from 4 miles out, landed, taxied off, shut the mill down and found top and bottom through-bolts on the two rearmost cylinders both failed, a straight shear with a martensitic appearance across the bolt at the thread and the last piece appeared to be more of a plastic failure. Negligable signs of fretting of crankcase, but it's probably in need of line-boring. Engine rotates freely by hand and still has good compression, but it's probably in need of a bulk-strip and zero-timing. Basically, the engine is probably toast. Now it's a case of how much to zero-time and upgrade this unit versus how much for a zero-time upgraded engine from stock.

Incident report sent to RA-Aus, engine going back to Jabiru as a running-core at time of shutdown.

Come on guys, my Rotax 582 lasted longer! It did 762 hours and was still running perfectly when it had a rebuild due to a failing alternator.

Now, are we going to get a service bulletin requiring us to replace all the trhough-bolts and studs at 500 hours (the traditional line-of-least-resistance), or will the manufacturer finally come up with a through-bolt with either a round or square thread, rolled into the bolt instead of cut, and a bolt of sufficient diameter to last at least 1000 hours?

Alternatively, re-manufacture the crankcases with a web for bolts to hold the crankcase halves together and fit separate studs to hold the cylinders. Hey, it works for Lycoming and Continental! The Jabiru 2200 engine in its present configuration is just about at its working-limit. Time to bite the bullet and start making it like a proper aero-engine.

Gentlemen,

we are starting to get a little inflamed about the tragic accident, and in fairness to the pilot I think we ought to pull back a little and let the pathologist and coroner do their work. We cannot yet know precisely why what happened did take place, and perhaps even after the specialists have done their investigative work we may still not have a definitive answer for actions which appear inexplicable.

We have an event which is irrevocable, final, and very confronting. Now we must allow the experts to carry out their duties. If we are to continue the discussion on these forums, cool heads will serve us best. Speculation as to what might have caused the accident is not helpful. Hypotheses about what we can do to prevent such an accident in futue are likewise useless until we know the "why" of the present situation.

For the present, the facts and only the facts should be our focus.

Two independent sources, both official.

This affair is assuming a darker appearance than just an unfortunate accident:-

Trike apparently un-registered (technically un-airworthy).

Pilot apparently hadn't flown a trike for many years (un-current).

Pilot apparently unable to rig aircraft without assistance (competency issues?).

Pilot advised by people on ground not to fly due conditions (airmanship issue?).

Pilot not trained on particular type of wing fitted to trike base (training issue?).

I am not sure how many other basic rules have been broken here, but there appears to be a chain of deliberate errors which have been contributory. It is beginning to add up to what can most charitably be described as a wilfull disobedience of basic safety rules.

Apologies if this appears harsh.

This is very sad news. My sincerest condolences to relatives and friends.

Technically for AM radio receivers we should refer to a sensitivity of so many microvolts at the antenna input for so many dB signal-to-noise.

My radio training dates from 1980 and is therefore a little dated, but I seem to recall the input sensitivity of AM broadcast receivers were usually rated at a few microvolts (say 2-5uV) at the antenna input for 20dB signal-to-noise.

A single sideband receiver was a more sensitive beast, down to below a microvolt or less if the front-end was really hot or used a special low-noise amplifier, which specialised communications receivers did (the 40673 dual-gate IGFET springs to mind). These sensitivity figures relate to superheterodyne receivers, but I think much the same applied for tuned radio frequency receivers on the AM broadcast band - somewhere between 2-5 uV for 20Db would be fairly normal. However, the AM broadcast band is Medium Frequency. We need to be careful lest we try to compare apples to oranges.

Aircraft radios are all superheterodyne receivers, and probably double-conversion ones at that with a first IF higher than the received frequency for better image-rejection. (The second IF is most likely the ubiquitous 455Khz.) The transmissions take place in the high-band VHF portion of the radio spectrum, and the bandwidth of the transmissions is necessarily narrower than AM broadcast (we only need "communications quality" audio on aircraft radios), but I still think the sort of sensitivity at the front end would be still be a couple of microvolts for 20dB signal-to-noise. Basically the front-ends of aviation-band radios are designed for the field-strengths typical of radio waves propagating through free-space, unimpeded by ground or absorption by surrounding landforms etc.

We also need to bear in mind the operational characteristics of our radio use; isolated and intermittent periods of transmission at relatively low power across a range of frequencies. Generally, our runs of coaxial cable are relatively short (a couple of metres is about the longest run of coax you'd ever need on a trike), and the loss in dB per metre is relatively small. However, the loss in dB is the same on receive as it is on transmit.

We require a radio system which has enough radiated field-strength from the transmitter and antenna (the transmit system) to enable us to communicate over a range suitable for the characteristics of the aircraft, and receive system performance to clearly receive transmissions from aircraft within a reasonable distance of our own for safety-related or other operational requirements. In the process of rigging our cables we have to use a certain number of connectors, and a length of cable. We also have to choose where to mount both the radio itself as well as the antenna. Invariably we compromise, but compromise is one thing; using cheap and poor-quality cable or lossy connectors is quite another.

In an ideal world, the top of the kingpost really is the best place for the antenna. But the world of trike-flying is far from ideal. The best compromise mounting-position we can achieve that satisfies the requirements for transmit and receive performance is more than adequate. If that mounting position allows for convenient manoeuvring in and out of hangars, or easy access for installation/removal of the antenna when rigging/de-rigging, then we have a workable solution.

I think we have enough evidence from the recent posts to conclude that mounting on the sting, either vertically upwards or in an inverted position, will suffice perfectly adequately, provided there is no de-sensing of the receiver due to nearby electrical fields emanating from engine electrical systems.

Test-flew the re-located antenna this morning for 2 hours at 4500 feet and found no impairment to reception of YWOL CTAF (127.3), Sydney Radar (124.55), Nowra Approach (123.5), Melbourne Centre (121.2), Sydney Approach (128.3), Sydney Departures (129.7), and Nowra Tower (118.85). YWOL AWIS (120.35) also boomed in, although it can be a little unreliable below 4500 feet west of Moss Vale.

When you are orbiting at 4500 feet you can do a lot of eavesdropping!

As this spread covers 11Mhz of bandwidth and includes all the frequencies we might reasonably be required to use, I conclude that mounting your radio antenna at the rear of the wing (on the sting or on a stub in place of it) is operationally as efficient as mounting it at the top of the kingpost, with the added benefit of reducing the height-clearance issues for getting the rigged trike into the hangar.

No ignition noise breaking through the squelch was detected using normal squelch settings (as if the antenna were still mounted on the kingpost).

"Gentlemen, mount your antennas!"

If most aircraft transmit vertically-polarised signals on the comms radio (i.e. electric field propagates in the vertical-plane) and you mount your antenna horizontally (which will receive the electric field component propagating in the horizontal-plane) then you will get several dB signal loss, depending on the angle betweeen the receive antenna and the plane of the electric field. In theory, that is.

The name of the game is to maximise the transmitted field-strength in the primary lobe of the antenna radiation-pattern, and maximise the number of microvolts at the antenna terminal on receive. A resonant antenna, impedance-matched to the transmission-line and mounted in the clear, free of shielding by adjacent structures, will achieve both, all other things being equal.

If the antenna for the transmitter and that for the receiver are at exactly ninety degrees to each other then the signal loss may exceed 30dB (ten raised to the third power), but this in practice is rarely achieved for anything other than very brief time periods due to the movement of aircraft around the fore-and-aft axis. However, to maximise received signal strength it is prudent to mount your comms radio antenna so it is vertically-polarised (i.e. the whip is vertical when in level flight). Ground stations transmit aircraft comms vertically-polarised, as do most aircraft.

It should be noted VOR transmssions are horizontally-polarised which explains why VOR receive antennas on aircraft tend to be folded whips or blade antennas mounted horzontally, often in the vertical fin. If you have a combined COM/NAV radio, or are using a second radio for VOR reception, then the antenna for the NAV receiver should be mounted horizontally.

The V-Rabbit antenna is a very good solution and works extremely well for the comms radio. I consider it to be well worth the investment.

Having become very browned off with striking the tip of my kingpost-mounted radio antenna on the hangar door, I have recently moved it to a small stub of tubing mounted where the sting for the Cruze wing normally resides. I'll put up with any slight shielding by the kingpost for the convenience. In practice there will be little discernable difference in radiation-pattern anyway. The underside of the antenna is a null-point, so this will minimise any potential ignition-system noise.

Coaxial cables are lossy; use the shortest practicable length and use the highest quality cable you can afford, properly-terminated with good quality connectors. An "air-gap" can cause major attenuation of both transmitted and received signal.

Ran a couple of hundred litres of BP Ultimate in my J160C just before the 500-hourly to see if it would clean out some of the lead deposits. It might have cleaned out a little bit, but when I hauled the heads off there was still a lot of yellow lead-oxide deposits on the piston-crown and around the head. To see any real benefit, you'd need to run exclusively on mogas for several hundred hours. I never tried Vortex 98 or V-power (or its pre-decessor, Optimax).

My biggest issue with BP Ultimate was carburettor-ice. The engine was very prone to ice as soon as it started and needed several minutes running at about 2000RPM with carb -heat on before it would deliver full power for takeoff. This was so severe I decided to revert to Avgas after the 500-hourly, and have run on Avgas ever since.

My conclusion is you can use any 98-octane RON mogas successfully in the 2.2 litre Jab engine, but keep carburettor-ice uppermost in you mind if the temperature is close to the dew-point and the relative humidity is anything above about 40%. Be prepared to spend several minutes ground-running at 200RPM to heat up the muffler so the carb-heat actually works and removes the ice before you try to take off. I actually printed out a carburettor-ice probability chart and laminated it so it can sit in the right-door pocket for ready reference.

Once in the air the engine ran beautifully on mogas, never missed a beat and gave smooth power with temps and pressures all in the green. The carby-ice thing was my only problem, and it was a significant one, especially in winter with low ambient temperatures and high relative humidity.

Garmin 495 is my "go-to" for an aviation GPS - a real aviation GPS, that is. It's in your budget and you won't regret buying one.

I have just done the 600-hourly on my 2200 engine which had the heads overhauled (new glacier-bushes, rocker-rods and exhaust-valves) at 500 hours. I also wrapped the exhaust headers all the way from the head to the muffler in glass-fibre exhaust heat-wrap (about $8/m from vehicle exhaust system specialists). The idea is to keep the exhaust gases hotter so they are less dense and flow out of the head more efficiently. Potentially this can result in slightly cooler exhaust-valves and valve-seats.

We observed no visible discolouration in the head inside the rocker area in the vicinity of the exhaust-valve. Previously there was a notable change in clour indicating localised heating. Cylinder-head bolts were all constant and none moved when torque-checked to 20 ft-lbs. So far, so good. This little mill has run the 600 hours in 2-1/2 years, on cross-hire.

Jabiru engines are built to run and run hard. Babying them is bad for them as it is for most aircraft piston engines. It's a good way to sludge up your Lycoming or Continental, and it also causes cylinder-wall glazing. Remember, your engine is air-oil and fuel-cooled...yes, the incoming fuel-air charge actually cools the cylinder-head as it is inducted. That's why aircraft piston engines tend to be set to run rich, especially on takeoff.

Regard the current incarnations of Jabiru cylinder-heads as 500-600 hour items. Somewhere about those hours be prepared to haul them off, do the valves, de-coke, check the cylinders and any upgrades to hydraulic-lifters, push-rods, rocker-arms etc. They are an easy engine to work on and the parts for a top-end job are cheap and available more or less "on-demand". Doing this is cheap insurance and may prevent a catastrophic engine-failure and a forced-landing.

FWIW, the leakdowns were 70/80, 70/80, 71/80 and 69/80, very good for an engine with 600 hours on it (100 since top-end work).

I also fly an aircraft with a Rotax 912 ULS engine, a reliable but complex engine with expensive spare parts and consumables (compare a Rotax oil filter with a Ryco Z386 for a Jab 2.2). I have great confidence in both engines because I do the maintenance, or I stand and look over the shoulder of the chap who is putting the spanners to it, and I ask questions.

It's hard to know too much about your engine.