The Bluebonnet Fly-In at Redbird Skyport has been rescheduled due to weather and the recent flooding in San Marcos. The new date for the Bluebonnet Fly-In will be Saturday, June 6th from 10am-4pm.
Hank Gibson of Texas Top Aviation will still be presenting on Garmin 430/530 Approaches this Saturday at 2pm in the large conference room at Redbird.
Recently, I assisted with the delivery of a 2007 Piper Saratoga Turbo from San Antonio to New York City. It was a very nicely equipped airplane, complete with a Garmin G1000 panel, an STEC 55x autopilot, and air conditioning. The owner joined me on the flight back to get trained in the airplane, getting him comfortable in it over our 2 day excursion back to NYC. Total flight time was 12 hours, though that did include several stops along the way and landing practice at the airports we stopped at.
The 6 seat Turbo Saratoga is a very comfortable, very capable flying machine. It is made for hauling, with a gross weight of 3,600 pounds, but that’s not to say it isn’t lacking in comfort, either. The rear cabin has 4 seats, 2 facing forward and 2 facing rear. It would be a little tight for 4 full size adults in the back seat. To avoid knee knocking, the plane is an excellent 4 person and bags aircraft (or 4 adults and 2 kids).
The really nice part about the Piper Saratoga is the baggage door. Unlike the Bonanza, the Piper Saratoga has a baggage door that opens to the baggage compartment, creating a much easier way to load and unload baggage. The nose baggage compartment, which holds an additional 100 pounds, is a very nice feature, allowing the bag load to be spread out.
We typically saw cruise speeds of 155-165 KTAS depending on altitude. The highest we went was only about 9,000 feet, so we didn’t get up real high to see what the single turbo could do. Even though the Lycoming TIO-540 engine burns about 20 gallons an hour, with 102 gallons of gas on board, the fuel consistently outlasted our desire to continue flying.
Being equipped with the G1000 was a very nice feature of this particular Piper Saratoga. The screens are nice and big, larger than the displays on a high wing Cessna or a Corvalis. That allows for easier viewing of approach plates, NEXRAD, and the engine gauges.
There are always downsides to an airplane, and the Saratoga is no exception. The STEC Autopilot leaves some to be desired as I felt it hampered the capability of the G1000 when shooting approaches because the 12 knot crosswind limitation on the autopilot. You can still use the autopilot on an approach with higher than 12 knot crosswinds, but the autopilot tends to search around for the final approach course.
The air conditioning works very nicely, though it did have a tendency to freeze up at altitude. We discovered that quickly and just decided to turn it off and leave the blower on, since it was cool enough up high anyway.
Overall, the Turbo Saratoga is a very nice airplane. The speed leaves a little to be desired (you can get 10 KTAS more out of a Bonanza with a Continental engine, about 20 knots more if it is a Turbo Bonanza), but it is very high on comfort. The Piper Saratoga makes for a good family airplane or as a hauler. I liked the airplane a lot and thoroughly enjoyed my time in it.
The PT6 engine that’s found on the Jetprop and Meridian is designated a -21, -34,-35, or a -42A. The Continental engine on a Malibu is either a TSIO 520 or a 550. What’s the difference? Why should I care? Most pilots don’t understand the difference, but it’s pretty easy to understand…and it’s all about breathing.
Whether a piston or a turbine, the engine has a ratio of fuel/air that works best. For a piston model, we can make adjustments to this ratio by adjusting the mixture. In climb we use a richer ratio to help cool the engine, and in cruise we lean the mixture to save fuel since we don’t need the extra fuel for cooling (due to higher speeds which cools the engine). In the turbine, the ratio is set and there’s nothing that can be done about it…except climb to a higher altitude. But, more about that in a second..let’s go back to the piston discussion…
Piston: A Continental 520 engine and the 550 engine are flown exactly the same. On takeoff, both will develop 310HP (38″MP with the 520, 35.5″MP with the 550). So, why would a pilot want a 550 in his airplane as opposed to a 520? The answer is breathing.
A 520 is named appropriately because the engine displaces 520 cubic inches of air with each complete cycle of all 6 cylinders. To determine the displacement, just figure the bore (diameter of the cylinder) and the Stroke (how far the piston travels in the cylinder) and plug the numbers into this formula:
CID = Bore X Bore X 0.8754 X Stroke X # of Cyl.
Here’s the bore and stroke of the Continental 520 and 550 engine:
TSIO 520: Bore = 5.25″ and Stroke = 4″
TSIO 550: Bore = 5.25″ and Stroke = 4.25″
So, you can see the two engines are exactly the same except the 550 has a little longer stroke, and therefore displaces a little more air. Said another way…it the sucks the air into the engine a little better.
So, with this knowledge, the ability for the engine to breathe becomes a little more clear. Both a 520 and a 550 will perform exactly the same until the point that a 520 simply cannot suck enough air and begins to develop less MP as a result. For most 520 engines, this will happen somewhere around 18,000 ft. But, it is dependent upon a myriad of factors including: health of the engine, altitude, temperature, and atmospheric pressure. When the 520 hits this point, the throttle can be full-forward, but the engine will not develop full MP, but some number that is less. I’ve seen a max MP at FL250 in a 520 Malibu to be about 31″MP. So, you can probably guess that the rate of climb will correspondingly suffer as the engine develops less MP. How do we fix this problem? Enter the 550…
Since the 550 displaces more air, the engine will maintain max MP to a higher altitude. When the 520 begins to develop less power at about FL180, the 550 engine will be able to continue to maintain 35″ at a higher altitude. Make no mistake…the 550 will also hit an altitude where is cannot develop 35″MP, but this altitude will probably be nearly FL220. So, the 550-powered Malibu will reach cruising altitude faster than the 520.
But, at cruise both engines are pulled back to 30″MP. So, either engine will deliver the same cruise speed because they are both able to develop 30″MP at any altitude. Does it really matter if you’ve got a 520 or a 550 engine? Answer: not much. Both are excellent engines and both will deliver the airplane to the destination, but if the chosen altitude is above FL180, the 550-powered airframe will probably arrive a few minutes earlier. Which would I want if I were purchasing an airplane? It’s not a big enough deal, IMHO. I’d select the best airframe/engine/prop combination and not put much weight into the 520 vs. the 550.
Turbine world: So, how about the -21, -34/35, and -42A compare? Here, there’s big difference, but it’s still all about the breathing. A -21, -34/35, and -42A are all derivatives of the famous PT6 family of engines, and all are designed to be 1000+SHP engines de-rated to fit the airframe. For instance, the -42A engine is 750SHP when mounted on a King Air 200, but the same engine is derated to 500SHP when mounted on the Meridian. Ditto with the -21 and -34/35 engines…all are de-rated. So what’s the difference? Breathing…
At the lower altitudes all will develop their maximum rated SHP, meaning they will all develop maximum torque. And, down low there’s plenty of air to breathe so the engine has no problem developing that torque at a low ITT. But, as altitude is gained, the engine must suck more air to develop the same torque, and the ITT goes up. At some point in the climb (depending upon altitude, temperature, pressure, and IAS) the engine will not be able to produce max torque without exceeding Max ITT. At this point, the engine cannot breathe any more (suck in anymore air), and the power (torque) developed falls off. With the -21 engine, the power falls off quite dramatically because the engine simply cannot breathe well. It is a smaller engine and more air cannot be forced into the compressor section. For the rest of the climb the engine is “ITT limited” and the performance will suffer.
The -34/35 engine is a little bigger and will develop maximum power (torque) to a higher altitude. And, when the torque does drop off (as altitude is increased), the rate of decrease is less because it can breathe easier due to it’s larger size. Guess what? The -42A will beat out the others and develop max torque to an even higher altitude. With this decrease in torque available also comes a welcome friend…less fuel burn. Altitude is the friend of any turbine pilot, and he/she will climb to the highest altitude possible to save on fuel.
The end result is the -21 powered Jetprop will cruise at 238 KTAS (in the summer) with a fuel burn of only 28gph. The -34 will have higher torque than the -21 and will develop more SHP and will have a higher cruise (260 KTAS in the summer) with a correspondingly higher fuel burn (32gph). The -42A will be breathing easily at higher altitudes, and will develop the most torque, but with a fuel flow of 39gph. The Meridian (with the -42A) will not out-perform the -34/35 Jetprop in cruise purely because the Meridian is much heavier.
Just remember…fuel flow in a turbine is always commensurate with its ability to breathe and a turbine’s ability to breathe is a function of the engine’s ability to breathe.
With this knowledge…let’s check your understanding. Answer this question: Will a Jetprop cruise faster in the summer or winter? Remember, cold air is more dense than warm air, and an engine will develop power according to it’s ability to suck in air. More air available, more power available. Answer: Winter.
A good analogy: I’m a Cross-fitter (meaning I do crossfit workouts a lot). In the gym we have various workouts that test a person’s ability to perform. Guess who usually does the best? Right…the guy who can breathe the best. A person is nothing more than an engine…we intake air and combine it fuel and burn it to develop energy. In Crossfit, the person with the biggest engine (muscles that can develop power) that can sustain power (good aerobic capability) will win almost every time. The only variables then are genetics (how well-made is the engine), flexibility (you’ve got to be able to get into the position), and skills (there are more efficient movements). A good Crossfitter will work hard on mobility, skill, and try to increase the bodies ability to increase capacity through a tough workout.
To get maximum performance, the pilot cannot change the engines skill or mobility (at least not without an engine change!), but a thorough understanding of the how the engine breathes will help him/her use the power that is available to the fullest.
Joe Casey’s aviation story began in 1990 with his first flight near Nacogdoches, TX in a Cessna 172. From lift-off, Joe knew he would have a lifetime passion flying just about anything that will leave the ground…He was completely hooked.
Along with being an FAA Designated Pilot Examiner (DPE), Joe is an ATP/CFI-AHMG and Commercial Rotorcraft/Glider Pilot in the civilian world and also a UH-60/AH-64 Pilot-in-Command/Instructor/Examiner Pilot in the US Army Reserves. His passion for the last 19 years, however, has been the PA-46 Malibu/Mirage/Matrix/Jetprop/Meridian. Has has amassed over 6,500 hours in various PA-46 airframes and believe it to be one of the finest flying machines available for the serious cross-country pilot with an eye for efficiency.
Now, Joe has flown more than 12,200 hours in just about every imaginable environment. Whether providing initial/recurrent training in the PA-46’s, TBM’s, instructing in NVG’s in a UH-60 Blackhawk, flying the King Air series of airplanes, giving tailwheel endorsements, or taking kids flying for the first time, he simply loves flying machines and the people who fly them.
I’m sure at this point, most pilots in Texas have heard about the Cessna 421 that went down two weeks ago in Lufkin. The Golden Eagle suffered a dual engine failure (the pilot lost the first at 2300 feet, then the second at 1700 feet) in IMC on climb out. He broke out at 1,000 AGL miraculously lined up with US 59, south of the Lufkin airport. The pilot had to dodge a car as he was attempting his landing, stalled the airplane, sheared off the landing gear, then slid into the median. No one died, but lots of bumps and bruises. All were airlifted to Houston.
The cause was a lineman at LFK put Jet A in the 421, which is a piston airplane and takes 100LL Avgas. The story that I saw said the pilot and two passengers were returning to Houston from Kansas City and diverted to LFK due to weather. They landed in driving rain and spent the night. I have not seen any reports saying whether the pilot sumped the tanks or not the following morning.
There were several factors that led to this accident. If you take one factor out, the accident probably wouldn’t have happened. Let’s take a look at the sequence of events.
The 421 arrived in a driving rain storm, so the pilot and passengers probably disembarked quickly to get out of the weather. Factor number 1 presents itself here. We don’t know whether or not the pilot told the lineman to put Avgas in it or not (he may have just said fill it up), so we’ll leave that aside.
Understandably, the pilot dashed inside to get out of the rain, but they neglected to monitor the fueling. Whether or not the fueling took place that night or the next morning, we can’t say. I have started to greatly encourage my customers to monitor the fueling of their airplanes, especially when it’s a fuselage that can either have Avgas piston engines or Jet A turboprops, as is the case with the Cessna 421.
Factor number 2, we already know about. The lineman messed up and put the wrong fuel in. If their was uncertainty about what type of fuel, he would have been prudent to await the return of the pilot to ask, even if that meant delaying the pilot’s departure.
Factor number 3 is the matter of sumping the fuel. We don’t know if the pilot sumped the fuel or not. The tricky thing about sumping is Jet A doesn’t settle out of Avgas like water does unless it sits for a long, long time. The two ways to determine if you have Jet A in your Avgas airplane are to smell it, as Jet A has a very strong diesel smell, or do the paper towel test. The paper towel test consists of dumping a fuel sample onto a paper towel, then let the Avgas evaporate. If you are left with a nasty, oily residue, you’ve got Jet A in your tanks (not to mention it will smell like diesel).
To prevent misfueling of your airplane, take the following steps:
Thunderstorms are not to be taken lightly. I know you have probably heard that many times in your flying career. Weather related accidents account for approximately 25% of airline and GA accidents.
The Airman’s Information Manual suggests giving a 20 mile berth around thunderstorms. If you are an experienced aviator or a newbie please take this piece of advice seriously. At one flight school where I taught, we had the policy of maintaining a 25 mile buffer around isolated thunderstorms. A bit excessive you think? Maybe, but safety is a good thing!
On this particular day, I was operating a Bell Jet Ranger helicopter during a power line patrol. Power line patrol by itself offers numerous challenges. The job consists of flying along electric power transmission lines at approximately 40 feet above the ground at 40 knots. The crew consisted of me (the pilot) and an observer. The observer is an employee of the power company and it is his job to determine which line(s) will be patrolled during the given day. As I fly along the lines, the observer is checking for anything out of the ordinary such as broken, cracked, or even shot out insulators, excessively large bird nests at the top of structures, or woodpecker holes in wooden poles. The observer knows the lines and he is also a great help in letting me know there is a crossing, and potentially higher, line in our flight path. That makes him a true safety asset!
It was late afternoon during the summer and we were about to finish up for the day. We only had about another 10 miles of line to follow before calling it a day. Up ahead, I noticed an isolated thunderstorm near our power line. I could see the heavy rain falling below the anvil shaped leading clouds. It appeared to be well beyond the end of our day’s work so we pressed on.
As we drew closer to the thunderstorm, we were suddenly tossed up on our left side like a dog toy in mid-flight! It seemed like we were 90 degrees to our normal cruise attitude and, to make it worse, we had the doors off on that hot summer day. I was able to recover and we did an immediate about face and high tailed it home. Forget the rest of that line, tomorrow is another day.
The destructive force of thunderstorms cannot be overstated. In addition to extremely heavy rain, they can contain strong wind shear, large hail, and severe turbulence, each of which can damage or destroy an aircraft. Take care when one of these bad boys is near your flight path. Give it plenty of respect and a lots of room, for safety’s sake.
Alan VanDoren is a 7000 hour ATP pilot. He has flown both fixed wing and helicopters as a police pilot, missionary pilot, flight instructor, and most recently as an EMS pilot. He has flown in five countries around the world and also teaches university level aviation courses in his spare time.
The FAA has decided to discontinue the dedicated En Route Flight Advisory (EFAS or Flight Watch) frequency 122.0. The effective date will be September 24th, but Flight Service will continue to monitor the frequency for an additional six months to direct pilots to Flight Service Station frequencies.
EFAS services will still be provided by Flight Service, though, on the published Flight Service Station frequencies (and 122.2).
To me, this makes some sense. In the past, if I accidentally contacted Flight Service on one of their frequencies to issue a pilot report or get a weather update, they would send me over to Flight Watch on 122.0. More than likely, the Flight Watch operator was sitting right next to the Flight Service operator, but I had to flip frequencies. This will help alleviate some confusion for pilots.
The deactivation of Flight Watch had been coming for years since the advent of Foreflight and other iPad and tablet apps giving pilots much easier access to weather, both in flight and on the ground. With Nexrad and Stratus, there isn’t much need for Flight Watch anymore (though you still can’t file a PIREP over the XM Weather!).
For more information, check out AOPA’s website.
AOPA recapped the year in the general aviation industry recently. A lot happened in 2016 including the certification of both the Cirrus Vision Jet and the Honda Jet. Several other manufacturers debuted new models, including Mooney with their Ovation Ultra and it’s 2 doors and Cub Crafters with their faster XCub.
To read the full year in review, you can read the AOPA Article here.
