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Stratos 716X

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Cirrus Vision Jet, meet your competition.

In July, Stratos Aircraft completed the first test flight of the single engine Stratos 716X personal jet. Stratos, based in Redmond, OR, is taking a page out of Epic Aircraft’s book in how the company is planning on bringing the Stratos 716X to market.

Epic Aircraft first released the Epic LT composite single engine turboprop in the early 2000s as an experimental. The first kit was completed and flying in 2005. Epic’s goal was to bring the airplane to market as a certified aircraft, a feat that took them almost 20 years to do, achieving full certification earlier this year.

Stratos Aircraft is hoping to learn a lot from their Bend, OR neighbors. The 716X is going to start off as a limited release experimental kit, while the company is working on achieving certification for the airplane. Once the plane is certified, it will be dubbed the Stratos 716. The 716X experimental kits will be assembled through a factory builder assist program (no garage built single engine jets here!). The kit will cost $2.5 million assembled, while the expected cost of the certified Stratos 716 will be $3.5 million.

Now, let’s talk about the airplane. 400 KTAS. One engine.

That’s right, you did hear correctly. The Stratos 716X is expected to cruise at 400 KTAS on only one engine. Compared to the Cirrus Vision Jet, that’s 100 knots faster. Think, “I’ll be relaxing at the hotel pool with a drink in hand when you are landing” type speeds. The fuel burn of the Pratt & Whitney JT15D-5 engine (3,000 lbs of thrust) is about 25 GPH more than the Vision Jet (the Stratos 716X will burn about 98 GPH of Jet A while the Vision Jet averages about 75 GPH of Jet A).

Comparing the two engines, the above numbers start to make sense. The Williams FJ33 engine on the Vision Jet only puts out 1,850 lbs of thrust, significantly less than the 3,000 lbs of thrust that the Stratos 716X Pratt & Whitney JT15D-5 puts out.

What does that mean to the pilot? In the Stratos 716X, it means less takeoff roll, better climb rate, faster cruise (as evidence by the 400 KTAS expected cruise speed), and a better payload. More power = more weight carrying capacity. And, the 716X is expected to have a service ceiling of 41,000 feet. I probably wouldn’t want to go that high single pilot with one engine, but I’d be very happy with that speed in the mid-30s.

The cabin, based on the pictures I’ve seen, looks very comfortable. The Stratos 716X seats 6 and can be configured in several different ways. Baggage is no problem as Stratos Aircraft stretched the fuselage from their original 714 Proof of Concept aircraft, adding a very roomy baggage compartment above the engine compartment. The passenger compartment is as big as a Phenom 100, providing more leg and head room than the Vision Jet. The front seats have plenty of legroom too, as Stratos has opted for a side stick instead of a yoke.

The avionics for the Stratos 716X are expected to be the Garmin G3X Touch for the panel which will be driven by a Garmin GTN 750 GPS. Autopilot will be integrated within the G3X. I would imagine that once the plane is certified, the panel will be switched to a Garmin G1000 NXi and a GFC 700 will be installed.

The genius of the design of the Stratos 716X is the aerodynamics of the engine placement. Instead of hanging the engine out in the slip stream and going with a drag inducing V-Tail like Cirrus did, Stratos took some notes from the myriad of single engine military fighter jets out there, placing the engine inside the fuselage. The fuselage is then built around the engine with two air scoops for intake directly in front of the wings. With two intakes instead of one, that leads to more air flow, which again, means more power. The Vision Jet has only one.

I’m going to keep tabs on the Stratos 716X (as I kept tabs on the Epic E1000). I’m hoping Stratos gets several flying soon (the company expects to do 3 kits a year till the airplane gets certified) and certification comes quickly after.

I got to stick my head in the mockup of the Stratos 716X when I went to Osh Kosh in 2018. I was very impressed and was excited to see the airplane was finally airborne this summer.

For more information about the Stratos 716X, check out the Stratos website.

Santa Fe Fly In Canceled

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Sadly, Texas Top Aviation is having to cancel it’s 2020 Santa Fe Fly In due to COVID. New Mexico has continued to implement travel restrictions, making it difficult for Texas Top Aviation to complete the event.

Mark your calendars now, though, as Texas Top Aviation has scheduled is 2021 Fly In. We are returning to the Lajitas Golf Resort in the Big Bend area of Texas. The event will be March 24th-26th, 2021. Stay tuned for more information. We hope to see you there!

An Educational Runup

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When a pilot thinks of an engine runup in a single engine piston airplane, typically it is let’s find out if the engine is running rough or not, meaning a spark plug is fouled.  Believe it or not, there is a little more to learn from a runup than just checking the spark plugs.

A distinct advantage to having an engine monitor that monitors all EGTs and CHTs is you get a better idea of engine health.  When switching to one magneto or the other during the runup, all the EGTs should rise, showing that the temperature of the exhaust gas is going up from each cylinder.  This occurs because when running on only one magneto and one set of spark plugs in each cylinder, the mixture takes longer to burn, so, when the exhaust valve in the cylinder opens, the burn is still on going and this hits the EGT probe, causing a temperature rise.  An indication of a magneto failure in flight would be a rise in all the cylinders EGT without a change in mixture setting.

Now that we know what to look for when checking each magneto, what would one look for to show that there is a problem?  The basic that each student pilot is taught still applies.  The engine manufacturer puts a limit on RPM drop during the runup.  When checking one magneto or the other, watch for an excessive RPM drop.  If the RPM drops past the limit, this usually will be accompanied by engine roughness.

Why is that?  Let’s look at the cause for the excessive RPM drop.  For this, we need to go back to our EGT indicators.  Let’s say we have a 6 cylinder engine.  When the key is turned to the right magneto, the RPM drops 250 RPM and the engine gets very rough.  Look at the EGT gauge.  The cylinders where the spark plugs are firing normally will all show a temperature.  The cylinder (or cylinders) where there is no combustion, meaning a bad plug, will show no temperature.  This is because the mixture is just sitting in the cylinder and not igniting, therefore, no exhaust gases will be pushed out so there will be no EGT indication for that cylinder.  This is also how you tell a mechanic which cylinder to check for the bad plug.

It could also be a bad magneto.  If multiple cylinders EGT all drop, or the engine wants to quit entirely, you have a bad magneto or bad ignition harness.

What else can you learn during the runup?  Electrical system health is key, especially in all electric airplanes (meaning no vacuum system).  It’s a very good idea to turn on all the lights and pitot heat to ensure that a rise is indicated on the ammeter.  This means the alternator is carrying the load and working properly.

The next time you do your runup, keep an eye on your EGT to see the rise during a magneto check.

Diamond DA50 RG

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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.

Contact Approaches

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Almost all IFR pilots are familiar with visual approaches and what the requirements are in order to fly a visual approach. As a refresher, the Instrument Procedures Handbook defines a Visual Approach as “an ATC authorization for an aircraft on an IFR flight plan to proceed visually to the airport of intended landing; it is not an [Instrument Approach Procedure]” (page 4-56).

For ATC to issue a Visual Approach, the pilot must have the airport or the traffic to follow in sight. Once the pilot reports the airport or the traffic in sight, ATC can clear the aircraft for a visual approach.

A limiting factor for a visual approach is ATC’s Minimum Vectoring Altitude. “This altitude, based on terrain and obstruction clearance, provides controllers with minimum altitudes to vector aircraft in and around a particular location” (Instrument Procedures Handbook page 1-42). ATC has to restrict aircraft to these MVAs, which can sometimes be quite high due to terrain or obstacles in the vicinity of the airport.

Every pilot has been in a situation with a high MVA that ATC can’t get them below, but it’s solidly MVFR or VFR at the destination airport. The MVA keeps the pilot in the clouds, so a visual approach isn’t possible since the pilot can’t see the airport or the traffic to follow. This can lead to extra time to go out and fly an approach.

Enter a Contact Approach. A Contact Approach is different then a Visual Approach. “The main differences between a visual approach and a contact approach are: a pilot must request a contact approach, while a visual approach may be assigned by ATC or requested by the pilot; and a contact approach may be approved with 1sm visibility if the flight can remain clear of clouds, while a visual approach requires the pilot to have the airport in sight, or a preceding aircraft to be followed, and the ceiling must be at least 1,000 feet AGL with at least 3sm visibility” [Instrument Procedures Handbook page 4-57].

Here’s the simplified explanation: A pilot does not have to have the airport in sight to request a contact approach. All that is required is for the airport to be reporting at least 1sm visibility and for the pilot to remain clear of clouds.

When would this be helpful for an IFR pilot? Good question. Here’s a scenario.

Pilot Smalls is about 20 minutes from his destination, which is an uncontrolled airport with only one approach to runway 17. He is approaching from the south and the initial approach fix for the approach to 17 is about 15 miles north of the airport. The airport is under Center control. When he has arrived at this destination in the past, Center usually could only vector him down to 4,000 AGL. He is very familiar with this airport and the surrounding area as he comes to this destination at least 2-3 times a month for business.

Pilot Smalls listens to the AWOS, which is reporting a 2500 foot scattered layer and 10 miles visibility. He knows it is right traffic for 17 since there is a 2,000 foot antenna on the east side of the field. There is some hilly terrain around, but all the terrain is well below pattern altitude and doesn’t cause a safety issue.

Looking out at the clouds, Pilot Smalls observes that the cloud layer is scattered to broken, but more scattered on the west side of the airport, with several large openings that he can see the ground through. Center asks for his approach request and Pilot Smalls requests a visual approach. Center gives him a descent to 4,000 AGL, their MVA for the area. They tell him to report the airport in sight for the visual approach.

At 4,000 AGL, Pilot Smalls is going through the scattered layer of clouds, but can see the ground in between the clouds and deems he has room to maneuver safely between the clouds and stay clear of them. He can’t see the airport, so a visual approach seems unlikely. He can’t cancel IFR because then he would have to keep the VFR cloud clearance and visibility requirements in Class E airspace (1,000 feet above, 500 below and 2sm horizontally), which isn’t possible in this case.

5 miles from the airport, ATC states, “N12345, I’m going to have to send you out for the approach since you don’t have the airport in sight.” Pilot Smalls then requests a Contact Approach. ATC clears him for the Contact Approach to his destination, so Pilot Smalls descends through a break in the clouds, remaining clear of clouds, until he gets below the base of the ceiling. He maneuvers onto the right downwind, lands and cancels IFR.

Contact approaches can be useful at controlled and uncontrolled airports. The first time you request one, do so with a higher ceiling and some room to maneuver to keep your safety margins. After you’ve done a few, you can determine what your personal minimums are for a Contact Approach.

I would not recommend doing a Contact Approach at an airport you are unfamiliar with. It’s vital to know what obstacles are around since on a Contact Approach, the pilot is now responsible for traffic avoidance and terrain avoidance, whereas on a visual approach, ATC resumes that responsibility.

For more reading on Contact Approaches and another good scenario, check out Bold Method’s article on Contact Approaches.