Monday, April 30, 2007

G1000 vs. GNS430 / 530

When I started my G1000 training, which comprised both theory and practice, the first question was "Are you current with the GNS430 ?". Yes was definetly the answer. I had extensive training and knowledge of the 430, on which my instructor insited a lot.

The G1000 trainer then said that I would have trouble with the G1000. What a surprise, and a douche froide (cold shower). Later on, I understood it was true.

What I will write here after concerns only the flight planning part of the G1000 / GNS430, in terms of instruments they obviously have nothng in common.

The good Garmin philosophy is respected by the G1000, so you find the FPL, Direct, CLR, ENT, PROC buttons, and the MENU key. What is new is the series of "soft keys". This is a series of keys below the screen, with no marking on them. Their function differs according to the currently used menu, and this function is indicated on the screen.

This is the big change you will have to deal with as a 430 user. Typically, when you finished to fill your flight plan in a 430, what will you do ?

Menu -> Activate ? Correct. But if you do so on a G1000, you won't find an "activate" entry in the menu. So, what ? Look at the soft keys below the screen, and one of them is labelled "Activate". That's the big idea of softkeys: offer the most frequently used functions directly.

The same applies to the procedures. To select a departure, press the PROC button, then the softkeys will become "select dep", "select arr", and "select app". So press "select dep", then the list appears, and one of the soft keys become "activate", so once you finished scrolling, press this softkey, and you're done. No more use of the menu key except for advanced / less frequently used functions.

Not only you can gain time with the softkeys, but moreover the corresponding items DO NOT appear in the menus anymore, and that's why my G1000 instructor was correct: in some aspects, being GNS430 proficient can be initially slowing you down when learning G1000.

More on G1000 NAV settings and engine performance in the next posts...

Saturday, April 28, 2007

G1000 - Get rid of the six-pack

Apart from plastic body (still no news about the gelcoat problem...) and plastic engine, the bigger change recently is certainly the plastic instruments - a.k.a glass cockpits.

This change has been made in steps, from years now, but the revolution is now complete.

One of the first step was probably electronic HSI like sandel tubes, which presented HSI on a small CRT tube, with additional route information. In parallel, GPS coupled with databases like the famous GNS 430 / 530 familly did bring moving maps in our cockpits.

An other step was the introduction of "low cost" inertial devices, allowing to replace the good old mechanical gyros, providing electronical attitude information.

Mix all of that together, and you obtain a G1000. I won't say a lot here on concurent product like Avidyne Entegra as I have no flying experience with them. However one must note one advantage of the G1000 over its competitors: it is the only one to integrate GPS and COM/NAV boxes. With Avidyne, it is still necessary to have separate GNSs.

So, when you fly a glass cockpit plane, the classical six instruments are all represented symbolically on the screen in front of you. And by represented, I don't mean "replicated as the mechanical". Typically, speed and and altitude indicators are in form of sliding tapes, not with round dials and needles.

My progression during the conversion to G1000 was in steps:

1) Get used to the HUGE attitude indicator that fills the whole screen
2) Find where information is
3) Sort out where the knobs are
4) Fly the bugs, not the figures

All of them will be detailled later, but here are a few words on each.

1) The vertical displacement corresponding to a given pitch change is much larger than on a classical horizon. This can be disturbing, when you're used to move your horizon by a few millimeters, to move it by centimeters to establish climb attitude.

2) Any IFR pilot is used to the T layout. This no longer exists with G1000, and even if the reading of the Primary Flight Display (PFD) is logical and easy, some training is needed.

3) In an electromechanical cockpit, each knob is situated in the corresponding instrument, i.e. baro setting on the altimeter, HDG bug and CRS selector on the HSI. As information is on the screen of the G1000, the knobs are all grouped on the side. Finding the proper knob can not be based on the instrument location, and there is noting worse than turning the baro setting instead of the CRS selector (based on my own experience...)

4) Even when flying with classical instrument, what we look at is the position of the needle, in the geometrical sense, not the actual values. Typically, when maintaining an altitude in cruise, one just manage to keep the needle vertical. This seems obvious, or even silly, but when flying with a G1000, there is no such thing, but a vertical tape with a bug you can set. The equivalent of keeping the needle vertical is to keep the bug aligned. Trying to interpret the figures displayed beside the tape is just not possible, and will lead to serious delay in the scanning.

As mentionned eariler, I will develop all of these topics, but the first conclusion is that conversion to G1000, even for VFR only, requires both theoretical and practical training. This is not an easy transition.


Friday, April 27, 2007

Trust the FADEC

When flying diesel engine, you have to trust the FADEC. In fact you have no other choice as it controls the engine.

This seems obvious, but if you're used to the classical three levers (throttle, prop, mix), you will probably feel out of control, or out of the loop, on your first FADEC single lever flights. This impression comes from the way we fly variable pitch props, which has nothing to do with what the FADEC does, because it is so quick and attentive to engine only.

A quick résumé for pilots not used to variable pitch prop:
High RPM for take-off
Slight reduction in climb above safety altitude
RPM reduction in cruise, to have a better engine efficiency
High RPM again on short final, in case of go-arround

With a FADEC, you just select an engine load, in %, and the FADEC decides an engine power and the appropriate RPM. The following diagram is extracted from the DA40D AFM, and shows the relation between engine load and RPM.

This shows that RMP will be maximal at full load, and then decrease, which is quite usual, and then decreases when power is reduced.

But when power goes below 20%, the RMP increases again. For three lever pilot, this means that even at low power the regulator is active, and that moving from low power to no power won't correspond to a prop slowing down !

This feeling is quite strange, and on some approaches in my first hours on diesel, I sometimes put some power back, just to be sure that the FADEC / engine couple was still working properly ! As you can imagine, the results was not exactly a stabilized approach ! I never had any bad surprises during an approach.

An other thing you can expect, is prop pitch change in turbulence, because the wind gusts in the prop will lead to RPM changes, and the FADEC will react to that immediately by adjusting RPM.

To summarize, you have no direct control over prop RPM, which can feel strange, but the gain is that you no longer have to monitor three parameters (MP, RPM, FF), but a single load, with a single lever, so pilot workload is reduced, which is good !

Wednesday, April 25, 2007

FADEC a.k.a. black box

Black box in light aircraft ? Affirm !

This is not by design, it is a byproduct of electronic engine management. As the FADEC controls the engine, it knows each and every engine parameter (temperatures, pressures, voltages, ...) and monitors all of them.

As a consequence, each time a parameter is out of the normal rage, the FADEC gives an alert to the pilot. This could lead to an apparent higher rate of alerts, but this is only due to the fact that the FADEC has nothing else to do than manage engine and generate alerts.

Can you, as a pilot, pretend that your oil temperature is never slightly above the limit during climb ? Be honest, you cannot monitor constantly all parameters, and the precision of the gauges usually found in light aircraft are not so accurate. Please don't missunderstand me, I'm not saying that FADEC are generating alerts all the time, or that we never saw parameters on limit values before. The only message is that FADEC helps in detecting transient conditions that could not be noticed with classical (and non-memorizing) gauges.

Thielert even put more safety in its FADEC, as some alerts can not be cleared by the pilot, but only by a mechanic. The flight can be continued, but if such an alarm occurs, the next flight will not be possible. The FADEC will not prevent to start the engine, but obviously no pilot will take-off with a warning on its engine control unit. Would you ?

After any problem, or during periodical maintenance, the mechanics will be able to access all these stored values and parameters. More on that later when I will post on some problems.

As a consequence, in collective flying (club, or shared ownership), some would feel that the FADEC is spying them, and that they could be blamed because of that. This is a purely psychological thing, especially as the pilot can not do anything wrong, except may be switching the FADECs off, or going to IDLE power at an improper time. But in terms of managing the engine, the only thing left is setting power, so how could you do something wrong ?

For maintenance people, this also provides improved way to monitor engine health, as they can follow all parameters over time. So yes, FADEC is a black box, and this is good for anyone.

Bis nächste... tschüss

Tuesday, April 24, 2007

Plastic engine - Operational aspects

Let' s have now a closer look to plastic engine operations. The first change compared to classical engine appears during pre-flight check. The good old oil level check is still present, but an additional check is needed: the level of coolant. This is because these engines are water cooled, so a visual check of the coolant level pops-up on the pre-flight checklist.

Engine startup is slightly different as well. The classical sequence looks like:

1) Electrical power on

2) Engine master on

3) Glow - No Glow

4) Startup

5) Check oil pressure within 3 seconds (yes, three, not thirty)

6) Warm-up

The engine master is the switch / key that turns the FADECs on. The point 3 is probably the most unusual for classical engine pilots. To burn correctly, the JetA1 fuel must be warm enough. For startup, there are "glow plugs", that bring cylinders and fuel to a good temperature.

The glow plugs activity is indicated by a particular light on the panel. After turning the FADECs on, the glow plug is activated, and then pilot must wait until the glow plugs are off before starting.

Starter can then be activated, either via a key or a push button, and normally, the engine fires-up quickly and easily. Here comes a BIG difference compared to AVGAS engines: the oil pressure must be in green range within 3 seconds !! If not, the engine must be stopped by switching the FADECs off. This very short time for oil pressure comes form the very high injection pressure.

Once started, engine can not be taken to more than 1400 RPMs before all temperatures (oil, cooling, gear-box) are in the green. This normally takes less than 2 minutes.

After taxi, comes the time of engine check. This is where FADECs help you, pilot, to save time. Just press and hold the ECU test button. Then FADEC "B" will be activated, and change prop pitch, after what FADEC "A" is re-activated, and also changes prop pitch. If all alert lights are off, the engine check is finished. The whole sequence lasts for about 10 seconds.

An additional check on the Diamond aircrafts, is to force activation of FADEC B (more on that in a later post), to ensure that both work fine.

Not more to say. For take-off, just push the power lever forward, check that more than 95% power is available, and fly. Full power can be maintained, as long as the temperatures remain in the green. In summer, it is better to reduce to 90-95% for the climb.

Most manufacturers recommend to fly in cruise with power setting arround 70-75%, but as I mentionned before, there is no restriction, and it would be perfectly legal to fly 100% all time.

One more advantage of water cooling is that power can be reduced to 0% at any time without any thermal shock risk. Quite helpful for high approaches. One must just note that most diesel engines are producing thrust even on IDLE power.

After landing, a cooling time is mandatory on Diamond aircrafts, but strangely not on Cessnas. The engine is stopped by simply switching the engine master (FADEC) to off. Be warned, these engine do stop quite abruptly.

More on engine parameters error reporting in the next post.

Monday, April 23, 2007

Plastic engine - JetA1 and FADEC

FADEC. The word is out. There has been a large buzz arround this word in the light aviation world for the last months, if not years. Thielert uses the acronym ECU, meaning Engine Control Unit instead, but have a look to the meaning of FADEC.

Full Authority Digital Engine Control. And to reword that in a "For Dummies" style: electronics controls your engine.

The kind of engine proposed by Thielert and SMA is a variation of the Turbo Diesel Injected automotive engines. I'm not expert enough in engines to go in the full diesel theory, but one important point is that diesel is injected under very high pressure (several hundred bars), to warm it.

The power delivered by the engine depends directly from the frequency and duration of the injections. We are here speaking of tousands of injections per seconds, so this is something that can not be controlled by a mechanical or human process, and this is where the electronics comes in the game.

The larger consequence of that is that in case of total loss of electrical supply, the engine will fail. Read that again, and think of it.

You should normally be partly scared now. But as you might guess, the engine manufacturers studied that in detail, and they propose various solutions, including dedicated backup batteries.

If you're a non plastic kind of pilot (yet), think of that. On good old Lycoming engines, there are two mags. But quite often there is a single mechanical axis driving both of them.

I know that I won't convice hard-core plastic opponents, and this is not my goal. Once again, I'm just exposing my experience.

Amongst the advantages of FADEC controlled engines, are:

1) Easiness of use - a single lever controls the powere delivered by the engine. No more prop / mixture lever
2) Easiness of use - A single button to press for engine and FADEC test
3) No carb heat, and under some implementations, no pumps
4) As a consequence of the no-mixture mode, no risk dirty of spark plugs
5) Tubro diesel means that maximum power is available up to at least 10'000ft
6) As engine are water-cooled, it is possible to go from full power to idle at any time without any thermal shock risks
7) Did I mention that a DA40 at 75% power, flying at 120kts, sips only 5.5 USG of JetA1 per hour ?

Obviously, there are some disadvantages, including:

1) JetA1 is not as easy to handle as AVGAS
2) JetA1 is more temperature sensitive than AVGAS, so fuel temperature must be closely monitored
3) JetA1 is denser that AVGAS, so water contamination is not so obvious to detect
4) When refueling on airports offering truck service, be sure that they send you the JetA1 truck, not the AVGAS one
5) As the prop is controlled by the smart FADEC, it changes RPM in way a human pilot won't use (like low RPM under certain low power conditions)

This post is kind of a summary of what will follow, as each of the points here above deserves a full post. I just want to close this post by two anecdots.

A long long time ago, I can still remember... I taxied a PA32 to holding point 23 for an IFR flight. During engine check, the mags test was so shaky that I was really close to cancel the flight. It took me more than 10 minutes at various power / mixture conditions to clean the spark plugs. Apparently the previous pilot did not knew how to use the mixture lever. After ten minutes, hopefully, my take-off slot was still 1 minute long ! No way this could happend on a diesel engine.

To remain balanced, an anti-FADEC story now. After taking of from an airport at 3'500 ft AMSL, climbing towards 7'500 ft (VFR flight), under 90% load to avoid overheating, the FADEC just "decided" that 65% was a better power setting. The black box shown that I did not moved the power lever. This reduced power condition did last for about 15 seconds, then 90% were available again. The rest of the flight was totally uneventful. By luck this did not happen after take-off from a short field.

A suivre...

Sunday, April 22, 2007

Plastic fuselage - Nothing special - Gelcoat issue

The first possible plastic component is the fuselage. From a pilot operation point of view, you can guess that flying metallic, fabric or plastic fuselage won't change anything. This is correct.

There are only two differences to be noted: planes with plastic fuselage are available in white, and possibly light gray. This is to avoid excessive sun heating that darker color could produce. There is not a long history on composite evolution over long term in aviation, but other industries use it for years now, so this restriction is probably based on strong reasons. However, this is not really restrictive, except for pilots liking pink or greenish planes...

Plastic fuselage also need different defrosting / deicing methods. Scratching frost or using certain de-icing fluids could severly damage the surface.

I must also report that one of the DA40 in my new homebase had to return recently to Vienna, because it has a so-called "gelcoat" problems. In fact, some bubbles formed under / in the paint. This was serious enough to have Diamond calling it back to the factory. On the positive side, Diamond made a replacement plane available. This is still a pending issue, so I will publish when everything will be fixed.

Saturday, April 21, 2007

Plastic airframes - What's on the market

At redaction time of this message at least three aicraft manufacturers do build plastic planes, namely:

Diamond aircraft which build single engine (DV20 Katana and DA40 Diamond Star) and twin engine piston DA42. The high performance single DA50, which made its maiden flight in early april.

Cirrus design offers various variants of its high performance single engine SR20 / 22, including turbo versions. One specific feature is its side stick, looking really airbus like.

Columbia also builds a high performance single engine, the Columbia 400.

Obviously, the new Airbus and Boeing planes, not to mention Embraer, are mostly fitting the plastic airframe criteria, but unfortunately, I did not found any club operating such planes until now. If you know one... please let me know.

Be selfish - few words about me

Before going any further, just a few words about my own flying experience, so you will know why to trust me... or not.

I started flying privately in 2001, on classical single engine pistons. I moved up to complex SEP, flying VFR and IFR on Bonanza and Saratoga (PA32R-301) in Switzerland (by the way, I'm not a native english speaker, sorry for any english mistakes in these pages). My first IFR ticket was issued in mid 2005. All of this was done on non-plastic planes. Presently, I totalize about 300 hours, of which about 75 under IFR.

The plastic experience begun on 21st of January 2006, when I had to change my homebase because of local restrictions affecting private operations.

The club in my new homebase has amongst its fleet two Diamond Star TDI (DA40D), so plastic planes with plastic engine, but classical instruments. As I had to change, I elected to also enter the plastic age. Now after a bit more that one year of plastic flying, including IR(A) renewal on a full plastic plane (DA40D with G1000), I decided to start this blog to share my plastic experience.

Thursday, April 19, 2007

Few words about planes and plastic revolution

A plane is made of three major components: the airframe, or fuselage, the engine (sometimes in packs of two...) and the instruments, normally located in the cockpit for pilot's use.

Some would argue that the pilot itself is part of the plane. This theory will be particularly "en vogue" by certain pilots who live true relationships with their planes, but no, the pilot is not part of the plane. MM Cessna and Piper never delivered any pilot, as far as I know.

Airframes have been made of a wide variety of substances, wood, fabric, paper, aluminium, and occasionally with addition of insects or birds.

Recently however, the plastic revolution took place. Ok, some like to call it "carbon fiber", or with even more complex names, including chemical formulae. Nevertheless, when you touch such a plane, or gently hit the wing (yes, gently only), it sounds just like plastic... because it is.

Let me be very clear. Wordings like "plastic plane" or "plastic flying" may sound cheap / unsafe / risky. This is not my point at all, and this blog is precisely about my own experience of flying plastic planes.

I just call them this way because it's fun, and fun is all what flying is about.

Back now on the three components of a plane. Airframe is easy, and know you can share my concept of "plastic airframe".

Engines are more a metallic thing. But just like plastic changes the airframes, a recent change happened in light aviation engine technology: turbo-diesel and FADEC. With that kind of engine, the pilot gets rid of many possible mistakes, a.k.a. prop and mixture lever, pumps, carburator heat, and so on. So to distinguish these new engines from the classical one pilots were used to, I call them "plastic" engines.

And what about instruments ? A bit before the plastic engine revolution, instruments moved from electro-mechanical individual dials, to integrated "tv-like" panels, that manufacturers names "glass cockpits". As they are LCD panels now, the term "plastic" cockpit would be better, would'nt it ?

Any plane can then be classified depending the ammount of plastic in it, from nothing to all plastic (airframe, engine, instruments), with all possible variations.

As mentionned above, this whole blog is about flying planes with plastic components, and I wish you plastic fun while reading it.