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Shortest Field You Are Comfortable Taking Your '62 Into?

Posted: Mon Sep 16, 2019 7:53 pm
by TomC
Just curious the shortest field you are comfortable flying your '62 into? Ideally out of too...

Assume sea level, ISA, and whatever weight you want. I know what the performance tables say, I'm just curious what others do in practice. I used to regularly fly my SR22 into 0B8 (Fishers Island, NY) which is 2300 feet and I always had plenty of room to spare. I'd love to go back to fish the the fall striped bass run, but not sure if it would be smart now that I fly a '62.

Thanks in advance for the thoughts!

Tom

Re: Shortest Field You Are Comfortable Taking Your '62 Into?

Posted: Mon Sep 16, 2019 10:13 pm
by rdrobson
Last week, with tower telling me to head straight to the numbers (I actually love it when that happens) and a regional jet behind me confirming with tower that they were really cleared to land with that twin Diamond in front of them, I turned off at the 2000' mark without feeling that I hit the brakes too hard.

That said, taking off in that distance would make me more nervous even though the book says ground roll should be around 1700'. Overall, I feel very comfortable going in and out of 3000' runways, but I probably wouldn't really want to commit to anything less than 2500'.

--Ron

Re: Shortest Field You Are Comfortable Taking Your '62 Into?

Posted: Tue Sep 17, 2019 8:32 pm
by jast
I did training in Donauwörth with a DA62, which is exactly 2300ft at 1300ft MSL. It was only me and a flight instructor, but rather big guys, 3/4of fuel and 40kg balancing weight in the baggage area. Was no issue at all. However there are also no high obstacles at this airport close to the runway. Wind was calm if I remember correctly (a few knots of wind from the front really shorten the TO). Also managed to take-off from a 3200ft well maintained gras runway with plastic reenforcements, fully loaded with 5 people plus luggage, 3/4 fuel at sea level. That was also working nicely with quite some buffer left. However the runway was so well maintained that it felt like concrete.

In preparation for this flight I learned that the DA62 has bigger wheels and a little more clearance, so grass runways are easier with a DA62 than with a DA42. However none of the planes are really optimal for grass...

Hope that helps,
Jan

Re: Shortest Field You Are Comfortable Taking Your '62 Into?

Posted: Sun Sep 22, 2019 1:44 am
by CFIDave
rdrobson wrote:
Mon Sep 16, 2019 10:13 pm
I feel very comfortable going in and out of 3000' runways, but I probably wouldn't really want to commit to anything less than 2500'.

--Ron
That's exactly my DA62 "comfort" level as well.

Re: Shortest Field You Are Comfortable Taking Your '62 Into?

Posted: Sun Sep 22, 2019 4:24 am
by Boatguy
CFIDave wrote:
Sun Sep 22, 2019 1:44 am
rdrobson wrote:
Mon Sep 16, 2019 10:13 pm
I feel very comfortable going in and out of 3000' runways, but I probably wouldn't really want to commit to anything less than 2500'.

--Ron
That's exactly my DA62 "comfort" level as well.
I'm kind of surprised. I did my PPL training at KSQL which is 2,600' and was serviced by part 135 Pilatus's and home to several part 91 King Air. Is that really outside the comfort range of the DA62? I'm not challenging anyone's flying decisions, just trying to understand the comfort zone for the DA62.

Re: Shortest Field You Are Comfortable Taking Your '62 Into?

Posted: Sun Sep 22, 2019 1:04 pm
by rdrobson
Boatguy wrote:
Sun Sep 22, 2019 4:24 am
I'm kind of surprised. I did my PPL training at KSQL which is 2,600' and was serviced by part 135 Pilatus's and home to several part 91 King Air. Is that really outside the comfort range of the DA62? I'm not challenging anyone's flying decisions, just trying to understand the comfort zone for the DA62.
Maybe I'm just paranoid, but I'm always thinking about engine failure when I start rolling above 70 KIAS. At that point, the end of a short field is approaching very quickly. So it can get outside of *my* comfort range, but the DA62 itself is feeling fine.

Re: Shortest Field You Are Comfortable Taking Your '62 Into?

Posted: Sun Sep 22, 2019 5:36 pm
by Colin
I talked to a pilot who wrote books about the DA40 and DA42 and asked him about SQL, since I was a new DA42 owner and thinking of picking someone up there. The question is not the takeoff distance or the landing distance it is the combination of the two.

The PC12 and King Airs have beta, so they have an *amazing* stopping distance given their weight. The DA*2s are relying on brakes. And, until I got my brakes upgraded, a braking system that I consider a little under-sized for the weight of the plane.

So my aviation mentor, John, said that he had an owner he was training who said the DPE wanted to start at SQL and did John think that was okay. They did the calculations and the DA42 (on that day, temp, etc) could get up to rotation speed and then stopped in the length of the runway plus fifty feet. John said it wasn't a regulation, nothing says you HAVE to use a balanced field length for the DA42, but the pilot should think about it. He said, "It's not a question of whether you can get in or out, it's a question of what happens if something goes wrong."

There are two fields (SQL and Novato) that I fly into where I know that if there is something catastrophic and EXACTLY the wrong moment I am going in the water. I have accepted the risk. I am not uncomfortably doing it, but you can bet that the cockpit is sterile and I am extremely focused at those two places.

Re: Shortest Field You Are Comfortable Taking Your '62 Into?

Posted: Sun Sep 22, 2019 8:42 pm
by jb642DA
I always look at the TO and Land charts based on Density Altitude.

For an abort at "rotation" - add TO roll and Landing roll together + 300' for startle effect time delay (2 seconds on average) in event of an abort (80 knots is approx 140 feet per second). If your runway is shorter than that, you know before hand that you'll be "going off the end". (note - AFM landing roll distance is based on FULL flaps)

The 2 second "startle effect" is average - some can abort quicker (test pilot who is making up the aircraft performance charts and has very little "reaction time" when the SHTF). Some will be longer, wondering "what's going on".

Some food for thought:
I also look at my "ONE ENGINE INOPERATIVE CLIMB PERFORMANCE" info from the AFM for each flight. (I keep a copy of the performance pages on my phone/iPad)

Just because the 42/62 has two engines doesn't mean it will be able to fly away from the ground.

Gear and/or flaps extended add a lot of drag. If you've never done a "drag demo" (a required item for MEI checkride) - Go and do it! You will get great performance info to know in the event of an engine failure - even more appropriate in regards to an "Engine Failure After Take Off" (or as the FAA calls it EFATO).
How long does it take for your gear to retract (our 62 is approx 7 seconds)
Just "gear extended" is approximately -400fpm in drag and it takes me at least 7 seconds to "eliminate" that "drag"!
TO flaps extended is about -300fpm of drag. How long does it take to go from TO flaps to "clean"?? - find out if you don't know.
Also, an inop engine with a windmilling prop is approx -400fpm.

So, at the weights I normally fly at (4600-4800# gross wt) and field elevation of 1000'MSL/70 deg - the AFM says, (based on 4850# weight AFM data) and these Conditions:
- Remaining engine .................... 95% load
- Dead engine ........................ feathered and secured
- Flaps .............................. UP
- Landing gear ........................ retracted
- Airspeed............................ Vyse
- Sideslip ............................ one ballout, max.5°bank

I should see about +190fpm rate of climb!

So, if gear and TO flaps are extended, and an engine fails at 20' AGL, what's going to happen? How about with just gear extended?

Will you "fly away" or not? Like I said earlier - "Food for thought".

Re: Shortest Field You Are Comfortable Taking Your '62 Into?

Posted: Sun Sep 22, 2019 9:04 pm
by rdrobson
jb642DA wrote:
Sun Sep 22, 2019 8:42 pm
- Remaining engine .................... 95% load

I should see about +190fpm rate of climb!
One point on the 95% power rating, I know that if I had an engine failure right after TO, I would not be too concerned about prolonging the time at 100% until after I felt that I was adequately clear of terrain and whatever obstructions there were.

Also, since ROC is strongly dependent upon excess horsepower, that extra 5% could make a considerable difference. It is only another ~9 HP, but that could make up a large percentage of your excess power and have a corresponding positive impact on max ROC.

--Ron

Re: Shortest Field You Are Comfortable Taking Your '62 Into?

Posted: Sun Sep 22, 2019 9:08 pm
by jb642DA
rdrobson wrote:
Sun Sep 22, 2019 9:04 pm
jb642DA wrote:
Sun Sep 22, 2019 8:42 pm
- Remaining engine .................... 95% load

I should see about +190fpm rate of climb!
One point on the 95% power rating, I know that if I had an engine failure right after TO, I would not be too concerned about prolonging the time at 100% until after I felt that I was adequately clear of terrain and whatever obstructions there were.

Also, since ROC is strongly dependent upon excess horsepower, that extra 5% could make a considerable difference. It is only another ~9 HP, but that could make up a large percentage of your excess power and have a corresponding positive impact on max ROC.

--Ron
at best, I would "guess" maybe 50fpm extra - still not enough to overcome the gear and/or flap drag or the unfeathered engine drag!

Too bad Diamond doesn't publish this 100% number!!
I think the AFM says full power for 5 min max for "normal ops" - I'd certainly use it in the event of EFATO!