Cirrus Alternator Failure

A Cirrus is an electric airplane.  There are no vacuum pumps and therefore no vacuum driven instruments. The Klapmeier brothers did this on purpose, trying to make it a modern airplane.  No vacuum systems means no vacuum pump failures, hence there is a lower likelihood of instrument failures in IMC.

What Cirrus did instead was put a lot of electricity producing and storing devices in the airplane.  All SR20 and SR22s are equipped with 2 engine driven alternators and 2 backup batteries.  Alternator 1 is a 28 volt alternator (the amperage varies based on whether or not you have an air conditioner) while Alternator 2 is a 28.5 volt alternator.  There are 2 24 volt backup batteries, as well.  Battery 1 is also used for starting.

In traditional airplanes that have 1 alternator, an alternator failure can affect a lot of things.  Depending on how many electronics are in the airplane, the battery can get depleted quite quickly.

The Cirrus electrical system is quite ingenious.  It’s a little bit different based on whether you have an Avidyne Cirrus or a Garmin Perspective Cirrus.  I will discuss that further below.

The main goal of this article is to talk through what happens in the event of a #1 Cirrus Alternator Failure (an Alternator 2 failure actually isn’t a big deal at all, though Alt 2 is required for IFR flight), the procedure for trying to fix it, and a technique I have developed that makes the pilot’s job easier.  First, let’s go through the #1 Cirrus Alternator Failure procedure.

Alternator 1 Failure

In either avionics configuration, the Cirrus Alternator Failure procedure is the same.

  • Check and reset the circuit breaker for Alternator 1 (Reset only once)
  • Cycle the Alternator 1 master switch
  • If Alternator 1 doesn’t come back online, leave the Alternator 1 master switch off and shed load on the battery

Avidyne Entegra

The Avidyne Entegra has 2 busses, the Main Bus and the Essential Bus.  Alternator 2 isn’t set to come on until the engine RPM reaches 1700.  While on the ground, Alternator 1 runs both the Main and Essential Buses.  In the air, Alternator 1 runs the Main Bus and Alternator 2 runs the Essential Bus.  Since Alt 2 is 28.5 volts, the higher voltage won’t allow the power from Alt 1 to cross over and run the Essential Bus.  There are also 2 one-way directional diodes that prevent the voltage from Alt 2 to cross over and run the Main Bus.

Having said all that, when Alternator 1 fails, Battery 1 is now running the items on the Main Bus.  There are a significant number of items on the Main Bus which causes the 24 volt battery to quickly lose it’s charge. This precipitates the need for shedding load.  Items like GPS 2, the air conditioner and aircraft lights can all be turned off.

In the above scenario, Alternator 2 is running the Essential Bus still that has all the Essential items on it.  Those include:

  • The PFD
  • Flight Instruments and associated Avidyne computers
  • Engine Instruments and associated Avidyne computers
  • GPS 1
  • Com 1
  • Nav 1
  • Autopilot
  • Stall Warning
  • Charging Battery 2

Note 2 important items that are not on the Essential Bus:  the flaps and the landing light (which is very handy at night).  Those two are only on the Main Bus, which Battery 1 is now powering.

Let’s further enhance our scenario.  You are flying over Nevada (quite remote and not a lot of airports) at night, 30 minutes from the nearest airport when your Alt 1 fails.  When you get to the airport you are planning on landing at, you want to have your flaps and your landing light, but we don’t know how long Battery 1 will last.

The solution (this is where my technique comes in):  Turn off the Battery 1 master switch.  This is an easy solution to ensuring you have battery power to use your flaps and landing light.  Instead of going through and shedding load, simply turn off the source.  You’ll still have all the above items on the Essential Bus, which is all you need to keep safely flying.  Then, when you get to your landing airport, turn Battery 1 back on to utilize your flaps and landing light.

Garmin Perspective

Cirrus wired the Garmin Perspective plane a little bit differently.  There are now 2 Main Buses along with the Essential Bus.  Alternator 1 runs Main Bus 1, while Alternator 2 runs Main Bus 2 and the Essential Bus. Both Alternators are running all the time.  The Alternator 1 Failure procedure remains the same.

The cool thing that comes along with the second Main Bus in the Perspective is the amount of items you still have available to you in the event of an Alternator 1 failure.  The only items you lose will be:

  • Yaw Damper
  • Landing Light
  • Air Conditioner and associated components
  • EVS Camera
  • 12 Volt power supply in armrest

Everything else is powered off of Alternator 2.  That’s not much.  The only item you really want on the above list is the landing light if you are going to be landing at night.

Follow the Alternator 1 Failure procedure, then do my technique again.  Turn off Battery 1 to save the battery power in order to use the landing light when needed.

Cirrus did a great job creating an all electric airplane with plenty of backups in case something fails.  I focused mainly on the Alternator 1 failure here.  If Alternator 2 fails, the system is wired for Alternator 1 to run everything while still charging Battery 1 and 2.  No big deal.

In my experience, turning off Battery 1 to conserve battery power is just a simpler solution when shedding load in the event of a Cirrus Alternator Failure.

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  • Preventing Gear Up Landings

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    Image credit: Aviation Consumer

    On the evening of November 3rd, 2015, I was returning to my home airport of Lancaster from Pittsburgh in my company’s Aerostar, after being out on charter all day. It was dark out as I entered the traffic pattern at Lancaster. After an uneventful approach, I was cleared to land behind a Mooney. The spacing looked good as I turned final, but, as I was nearing the threshold, I started to become concerned that the Mooney wouldn’t be clear of the runway in time for me to land. At that moment, over the radio I heard an uncomfortable transmission from the Mooney pilot: “Tower, Mooney ABC has landed gear up.”

    It took the tower controller a minute to grasp what was going on, and I was on about a 1-2 mile final when I was instructed to go around. Thankfully, the Mooney came to a stop in such a position that I was able to use the other intersecting runway, and was on the ground only a few minutes later. I can assure you, however, that I’ve never checked my “3 green” so many times in one traffic pattern as after that incident. Thankfully, no one was hurt, but there sure was an impressive amount of emergency equipment on the runway as I taxied back to my hangar.

    In aviation, there’s a saying that goes: “There are two types of pilots. Those who have landed with their gear up, and those that will.” I don’t like that saying. The potential of a gear up landing (as a result of pilot error) is something that has always been a risk that I have worked hard to avoid. Not only is a gear up landing embarrassing; but it’s also an extremely expensive black mark on any pilot’s career.

    image
    Not a good day. (Photo credit: http://www.newsday.com/long-island/suffolk/plane-lands-at-republic-with-no-wheels-1.2735131)

    According to a July 2006, article in Aviation Consumer, the estimated cost of repairs following a gear up landing for an A-36 Bonanza would be about $27,000 and about 3 weeks of down time. 25 years ago, even my beloved E33 Bonanza was the victim of a gear up landing. While it was neither me nor my dad flying our airplane that day, the event stays in its history and reduces its value should the time ever come to sell it.

    That incident in 1990 resulted in approximately $25,000-30,000 in repairs. The cause of the incident was classic: the pilot put the gear down at the normal time, but then had his downwind extended by tower. He brought the gear back up to fly the longer downwind, but forgot to put it back down later when he was cleared to land. Like many pilots, he had a set routine time when he normally put the gear down, and when his routine was changed, he didn’t remember to lower the gear once more.

    Unfortunately, no matter what experience level one may be at, no pilot is immune to the possibility of such a mistake. The following are 5 tips that I have learned in my time flying that have helped myself and others minimize the chance of a gear-up landing occurring:

    1. Know your aircraft systems: What are the operating perimeters on your airplane’s gear warning system? Most airplanes have a designated speed or power setting at which the gear warning horn will sound in the event that the gear isn’t down and locked. In the Aerostar that I was flying, the gear horn was supposed to come on at 15” of manifold pressure with the gear up, but in practice, it didn’t come on until much lower than that. It has since been adjusted, but at the time it was important for me to know that if I had left the gear up, the horn wouldn’t have sounded in a timely enough manner for me to go around, much less lower it prior to touchdown. Most likely it would have just added to the noise of metal on concrete as I pulled the power all the way back in the landing flare.
    2. Don’t override gear-up warning systems: They were put there for a reason! Even if you’re out doing maneuvers and the horn is blasting in your ear for half an hour, resist the temptation to simply pull the circuit breaker or push the warning silencer to make it shut up. If a pilot disables the gear-up warning horn and then later forgets to put the gear down on landing, he or she will have a much worse headache on their hands than the one that the horn would have given them.
    3. Use your checklists and memory items: It doesn’t matter how much a pilot knows about his or her airplane, or the procedures for it. Distractions happen. Mistakes Happen. Always consult the checklist for confirmation that you’ve accomplished all the essential tasks before landing. Additionally, if you haven’t already, work on developing call outs which you perform out loud regardless of whether you are alone in the airplane or not. Whenever I’m landing an airplane, I start with my flows, go through my GUMPS (Gas-Under carriage- mixture- props- seat belt) checks, then do the printed checklist, and finally when on short final I call out “short final, cleared to land, three green.” I’ve had several passengers tease me about doing the “three green” call out while I was flying aircraft that didn’t have retractable landing gear. But, I’d much rather be in the habit of checking every time regardless of what I’m flying than forgetting to check when it is necessary.
    4. Use your available resources and develop healthy habits: If I have someone riding with me, I generally ask them to confirm that there are 3 green lights glowing on the instrument panel. Even if that person isn’t a pilot, they will probably enjoy the opportunity to be involved, and it’s a good way for me to stay in the habit of checking the gear lights to ensure that everything is properly down and locked. I’ve also found that intentionally leaving your hand on the gear lever until you have gear safe lights is a good idea. Forcing yourself to keep your hand on the handle until you have the all important lights obligates you to actually observe the indications instead of simply throwing the lever and moving onto something else. This way, if you only get an indication of 2 greens you’ll be aware of it right away and have more time to respond appropriately. It also helps you to learn the normal length of time it takes for the gear to extend or retract, which will be helpful to you to be aware of any abnormalities in the gear system.
    5. Upgrade your aircraft’s gear-up warnings: There’s a variety of ways you can improve your aircraft’s ability to warn you of a potential gear-up landing. For student pilots or pilots new to complex aircraft, it could be something as simple as a red post-it note on the panel to remind you to verify the gear position prior to landing. Or, if you own an aircraft that doesn’t have an effective way to warn the pilot of a gear-up landing, consider investing in an aftermarket gear-up warning system – surely the extra price of such an upgrade is a small amount next to the cost of repairing the damage from a gear-up landing!

    Crash recovery and emergency management crews survey a C-17 Globemaster as it rests on Bagram Air Field's active runway Jan. 31 after landing with its landing gear still up. More than 120 Airmen, Defense Department civilians and contractors successfully removed the crippled aircraft from the runway Feb. 2 and restored full air operations shortly thereafter. The "belly up," or no landing gear, recovery effort that began here Jan. 30 was the first time in the airframe's 16-year Air Force history. (U.S. Air Force photo)
    It can happen to anyone! The gear handle in this C-17 was in the “UP” position. (Photo Credit:https://theaviationist.com/2009/02/09/c-17-gear-up-landing-in-bagram-images/)

    Always remember, regardless of experience, no pilot is immune to the possibility of a gear up landing. The best way to safeguard yourself is to discipline yourself in the use of flows, checklists, and call outs. Things like gear warning horns, visual reminders, and other systems are a useful back up, but they shouldn’t be relied upon to save your bacon if you don’t get the gear down at the proper time. Fortunately, in most gear up landings, the pilot and passengers are able to walk away uninjured – but that doesn’t lessen the embarrassment or financial burden of the event. So, keep your chin up, your gear down, and remember….THREE GREEN

  • Fly Away Destination: Lajitas Golf Resort

    Talk about star treatment.  The Lajitas Golf Resort rolled out the red carpet for the 2019 Texas Top Aviation Lajitas Fly In.  I had been to Lajitas twice before; once in July when it was hot, miserable and bumpy.  The second time was the week before our Fly In.  Both times, everyone from the airport folks to the bus drivers to the front desk and restaurant staff were top notch.  It made for a very pleasurable experience.

    If you haven’t been out to Lajitas (or don’t even know where it is) and you’re a pilot (you don’t even have to play golf), you have missed a sure gem.  Lajitas is positioned on the southern tip of the Big Bend area of Texas, right on the Rio Grande river.  Lajitas has great lodging with several different room options from big to small, an excellent restaurant for 3 square a day (and even a bakery for sweets, coffee, and breakfast tacos in the mornings), and a 5 star golf course in Black Jack Crossing.

    Why is this all relevant to us aviators?  Lajitas has it’s own private airport, 89TE.  Complete with a 5,500 foot asphalt runway, VFR conditions most of the year, and reasonable fuel prices, Lajitas is the pilot’s gateway to the resort and the entire Big Bend area.  If you wait until the fall, a brand new, 7,000 foot concrete runway should be completed and an IFR approach should be available.  An AWOS is in the works too.

    The resort and airport are so far south, radar and radio coverage with Albuquerque Center is pretty poor below about 15,000 feet, and non-existent below 10,000 feet.  This isn’t a big concern as any airplanes in the area should be on 122.9 and the airport manager will make contact with you, give you a weather report, and assign a runway.

    Once you are on the ground, there will be a resort bus waiting to whisk you and all your friends to the resort for your getaway.

    The 2019 Texas Top Aviation Lajitas Fly In was a big hit.  We had 7 airplanes total:  5 Cirrus SR22s, 1 Piper Matrix, and 1 Citation M2.  There were 15 attendees total, including 13 golfers.  Everyone raved about the resort and the golf course.  The only hiccup in the weekend was the cold front that blasted through on Friday afternoon, kicking up a lot of dust.  Golfing on Saturday was windy too, but Sunday morning was absolutely perfect.

    Thanks again to the folks at Lajitas for the star treatment!

    Interested in participating in the next Texas Top Aviation Fly In?  Contact Us or Sign Up for Our Newsletter and we will make sure you find out about the next one so you don’t miss out!

  • MMOPA Operating Practices for the Piper PA46

    I have the privilege of serving on the Malibu & M-Class Owners and Pilot’s Association Safety Committee.  Along with 6 other Piper PA46 instructors, we were tasked with two things last year leading up to the MMOPA Convention in Colorado Springs last October.  The first was to develop a Master Aviator Program (more on that in a later article).  The second was to develop Operating Practices for the Piper PA46 fleet that we as instructors could all get on board with to teach the same thing, allowing everyone in the fleet to fly approaches and patterns the same way.

    When I started instructing in the piston Piper PA46 line (the Malibu, Mirage, and Matrix), I was surprised to find that there were no recommendations anywhere that I could find for approach and pattern power settings and airspeeds.  This led to some experimentation on my part trying to find out what works well for the airplane.  I had originally been given good training in a Malibu, but hadn’t flown one for several years, so my numbers were a bit rusty.

    I have been in the Cirrus world for a very long time.  One thing I greatly appreciated from an instructing point of view about Cirrus was the abundance of guidance the factory gives instructors and pilots on how the airplane is supposed to be flown.  All CSIPs and all Cirrus pilots should (theoretically) be teaching and flying the exact same way.

    I was quite surprised that Piper didn’t put out similar information.  I wasn’t as familiar with MMOPA at the time, but was surprised they didn’t have any information either.

    I apparently wasn’t the only one with a desire to have a little bit more standardization.

    So, without further ado, here are the MMOPA Operating Practices that the Safety Committee put together.  If you are a new Piper PA46 pilot, these numbers are what you will expect to use when you do your Initial training.  If you are a seasoned Piper PA46 pilot, you probably fly these numbers, or pretty close to them already.

    These are tried and true power settings and speeds for the approach phase and landing phase.  They work. That was the goal of the Safety Committee:  put down in writing something repeatable to enhance safety.  I believe we have accomplished that.

  • Flying WAAS GPS Approaches

    When flying a WAAS GPS approach, there are several different levels of WAAS signal that a GPS receiver can get. The most precise is an LPV signal. LPV stands for Localizer Performance with Vertical guidance. An LPV approach has the lowest minimums of all the WAAS GPS approaches, typically in the range of 200-300 feet AGL. A GPS glide path (GP) is guaranteed with an LPV approach and the minimum altitude is a decision altitude (DA).

    Just like a localizer, an LPV course width get’s tighter and the CDI becomes more sensitive the closer the plane get’s to the runway. Even though the LPV approach minimums are so low and the approach is down to a DA, they still aren’t considered precision approaches by the FAA (which leads to some extra planning when selecting an airport as an alternate that only has GPS approaches, since the AIM specifies only the LNAV minimum are to be considered if an alternate airport only has GPS approaches, bringing the 800 foot ceiling requirement to bear)

    An LNAV/VNAV approach is still a WAAS approach that has a GPS glidepath, but is slightly different than an LPV approach. An LNAV/VNAV final approach course does not get more sensitive the closer the plane gets to the runway. The smallest course width on an LNAV/VNAV approach is 0.3 miles either side of center. LNAV/VNAV approaches will, most of the time, have higher minimums than LPV approaches and can have minimums no lower than 250′ AGL.

    The third type of WAAS approach is strictly a non-precision approach with a Minimum Descent Altitude (MDA). These are designated LP approaches, which stands for Localizer Performance. These are like old school Localizer only approaches that, similar to the lateral portion of an LPV approach, the course width tightens the closer to the runway that a pilot is. There is no glide path by definition of an LP approach, though there is a caveat.

    Now, by looking at an approach plate that is a WAAS approach, but only has LP minimums listed, a pilot would assume there would be no glide path. Depending on what type of GPS unit the airplane has, that pilot could be wrong. Garmin Perspective units (Cirrus G1000), all GTN 750s and GTN 650s, All G1000 NXi units, most Garmin 430W and 530W, and all Avidyne IFD 550/540 and 440 units will display an advisory glide path on an LP approach, designated LP+V.

    What does LP+V indicate? An advisory glide path is just advisory, but it is totally legal to follow down on a non-precision LP approach. The kicker is obstacle clearance is not guaranteed and the pilot needs to keep an eye on minimum altitudes at the different waypoints on the approach. The big thing I tell people is, when you arrive at the MDA and the runway is in sight, following the advisory glide path below the MDA could get you in trouble with obstacles. Don’t just hone in on your instruments when you break out of the clouds. Look out the windscreen and make sure you won’t hit anything.

    If you arrive at the MDA on the advisory glide path and the runway isn’t in sight, DON’T GO BELOW THE MDA! Most autopilots won’t level off at the MDA, even if that altitude is set in the altitude pre-select, so this will involve turning off the autopilot before the MDA and manually leveling off, or engaging the altitude mode of your autopilot at the MDA.

    One other type of GPS approach that you will encounter is an LNAV approach. This is a non-WAAS approach down to an MDA, but your GPS unit may still give you a +V. Most modern ones will.

  • Diamond DA50 RG

    Diamond Aircraft announced in June that the company is going to bring it’s Diamond DA50 RG to market. The company expects European certification in early 2021 and FAA certification toward the end of 2021.

    This is not the first iteration of the Diamond DA50, but it is the first with retractable gear. Diamond is known for it’s use of Jet A burning piston engines and you can’t beat the efficiency. The technology in the Continental CD-300 Jet A piston engine is new, but it has been in development for a long time. Diamond advertises 180 knots on only 9 GPH, which is just about as efficient as you can get with a single engine piston.

    The addition of the retractable gear from previous iterations of the Diamond DA50 RG is a nice touch. Diamond already had the RG technology from the DA42 Twin Star as well as the more powerful cross country machine, the DA62. Equipping the single engine Diamond DA50 RG with retractable gear just makes sense. It definitely puts the airplane in a class of it’s own.

    Diamond’s website shows a nice roomy cabin in the DA50 RG with plenty of space to spread out, plus plenty of baggage. The fuel tanks only hold 50 gallons of Jet A (which still gives a 4 hour + range with an hour reserve at 9 GPH), so the payload, even with full fuel, is an eye popping 897 lbs, though Diamond’s site does not mention if that includes TKS, air conditioning, and oxygen. If it does, then compare that to a fully fueled Cirrus SR22T (which would give an equal speed) at 537 lbs and the Diamond DA50 RG has an argument.

    As with all new airplanes these days, the Diamond DA50 RG has the Garmin G1000 NXi complete with keypad and the GFC 700 autopilot with yaw damper. The interior has a 3 person bench seat for the back seat, which, at least to the naked eye, appears that it might actually fit 3 adults, albeit small ones. Diamond’s signature stick in the middle of the seat is still present for the front seats, but the right seat stick in the Diamond DA50 RG is removable for passenger comfort, a nice touch.

    The single engine piston market is a hard one to break in to since Cirrus has such a leg up on the competition. However, with a Jet A burning engine, a higher payload, and a roomier cabin, the Diamond DA50 RG might actually be able to make an impact. Look for this bird at Sun N Fun and Osh Kosh in 2021.

2 Comments

  1. Hank, this sort of thing is very helpful. Simple and effective!

    Now a question— The good Gen Hostage and I are gonna need a biannual check in about 6 months. Is there a good tutorial(s) somewhere that would be good?

    See Ya!

    Joe D.

  2. Great info…. Thanks!

    Side note I believe that a failure of Alt 1 (and Battery 1) with Perspective you will also lose the MFD too (Foreflight makes a great backup to that)

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