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

Posted: Mon Sep 23, 2019 1:34 am
by Colin
A friend did a sim ride as part of his multi-engine training, not a DA42 aircraft. His instructor failed an engine just after rotation and my friend knew he was meant to chop, drop and brake, but since it was a sim and he was curious he shut down the correct engine, kept the plane in ground effect and level while he raised the gear, and wiggled the rudder, elevator, rudder a little more, and got a *tiny* climb out of the simulated plane until he had it at TPA, flew the circuit and landed. The instructor said, "That was interesting, but don't try that in real life."

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

Posted: Mon Sep 23, 2019 2:17 am
by jb642DA
Colin wrote: Mon Sep 23, 2019 1:34 am A friend did a sim ride as part of his multi-engine training, not a DA42 aircraft. His instructor failed an engine just after rotation and my friend knew he was meant to chop, drop and brake, but since it was a sim and he was curious he shut down the correct engine, kept the plane in ground effect and level while he raised the gear, and wiggled the rudder, elevator, rudder a little more, and got a *tiny* climb out of the simulated plane until he had it at TPA, flew the circuit and landed. The instructor said, "That was interesting, but don't try that in real life."
Great story Colin and good advice!

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

Posted: Mon Sep 23, 2019 7:18 pm
by ultraturtle
TomC wrote: Mon Sep 16, 2019 7:53 pm Just curious the shortest field you are comfortable flying your '62 into? Ideally out of too...
Short answer (without having to reference the charts) is 5,350’. Now the long answer...

Over the years, I’ve observed that I generally need to fly out of any field to which I fly in, so my “comfortable field length” is based on takeoff performance. Best technique I’ve found to make the go/no decision on takeoff should I encounter an engine failure, fire, windshear, or inability of the aircraft to fly during takeoff is gear retraction. Any such event prior to gear handle up, and I abort. After gear retraction, I go fly. Good technique to calculate runway distance required for the worst case failure scenario just prior to gear retraction is to add distance to takeoff and clear a 50’ obstacle to landing roll. The worst case conditions for my regular flights would be max gross weight, 1,000’ pressure altitude, 90 degrees, with calm winds. The book says that works out to 5,350’. Takeoff plan for runways that long or longer is pretty simple. In case of any of the events noted above, I retard the throttles to idle, maintain directional control with rudder, get on the brakes, clear the runway, and go fix the problem or wait out the weather event.

Any field shorter than 5,350’, I simply run the charts based on actual environmental and weight conditions, and consider any runway longer than the addition of distance to takeoff and clear a 50’ obstacle to landing roll to be “comfortable”. Same takeoff plan.

That is not to say that I would not and do not land or take off on runways shorter than this criteria. It only means that I am not really comfortable, and need to adjust my takeoff plan. In the unlikely event that any of the above listed conditions occur prior to gear retraction, in addition to retarding the throttles to idle, maintaining directional control, and getting on the brakes, I also need to shut off both engine master switches, both fuel selector switches, the electrical master switch, then prepare for potential impact if the triggering event occurred close to gear retraction.

I would not have a problem landing or taking off on a field right at book value for distance to clear a 50’ obstacle, I just would not feel “comfortable”.

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

Posted: Wed Sep 25, 2019 1:11 am
by Colin
It is actually gear retraction which puts the slight panic in my heart, since there was the original DA42 crash that was related to that. I realize my plane has the added batteries and circuitry and all that. I still have a little uptick in heartbeat when I raise the gear. I am READY to put it on the golf course.

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

Posted: Mon Sep 30, 2019 5:09 am
by TwinStarScott
Since this thread was first started by Tom, Max Trescott released an episode on “Getting a Multi Engine Rating”. It’s a good general refresher for owners flying light twins and who aren’t also airline pilots. While this episode is naturally focused on six-lever Twins, there is still value for FADEC (only) pilots. One specific question that comes to mind, as it relates to this thread and interview is:

What is the maximum AGL altitude you would chop power on takeoff and land straight ahead? And for all, or some, of the various DA42 models / engines vs. the DA62?

This former C-130 pilot, now giving MEI instruction in a Beech Travel Air, uses this rule (for this make and model):

Anything “less than 500’ AGL” he is going to react as if he were flying a single-engine and land straight ahead (20 degrees, left or right of the nose). Regardless of loading and density altitude.

This statement starts at 45:48, but for better context, a good entry point is 42:55 (short of listening to the entire interview):

https://podcasts.google.com/?feed=aHR0c ... 9817572610

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

Posted: Mon Sep 30, 2019 7:07 pm
by jast
TwinStarScott wrote: Mon Sep 30, 2019 5:09 am
This former C-130 pilot, now giving MEI instruction in a Beech Travel Air, uses this rule (for this make and model):

Anything “less than 500’ AGL” he is going to react as if he were flying a single-engine and land straight ahead (20 degrees, left or right of the nose). Regardless of loading and density altitude.
Max Trescott‘s podcast is really good! I can recommend to listen to many of the safety related episodes!

I also listened to the MEP episode and the instructor said that reason for the conservative approach in his Beech is the danger of a Vmc-roll. I did my MEP training in LOAN in April and as far as I remember the DA62 actually behaved pretty nicely at Vmc. Obviously you loose yaw control, but I don’t remember it to be very sudden with not too much roll tendency and easily recoverable. But I only did that once or twice. Has anybody more experience to share with a DA42 or 62? How critical is a VMC roll in the Diamond twins?

Eventually my current approach would be: Takeoff and gear up as soon as no remaining runway is available. Until then I would go to zero throttle and land on the remaining runway with the risk to go beyond the threshold and damage the plane. After that moment would try to continue to fly and do a big, careful pattern into the working engine with a long and stable approach on final.

What I learned from another experienced DA42 pilot was:“ If an engine quits during takeoff, go and hold 6 deg pitch and then carefully go through PPAA (power, performance, analyze, action).

Thoughts?

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

Posted: Mon Sep 30, 2019 8:12 pm
by jb642DA
TwinStarScott wrote: Mon Sep 30, 2019 5:09 am Since this thread was first started by Tom, Max Trescott released an episode on “Getting a Multi Engine Rating”. It’s a good general refresher for owners flying light twins and who aren’t also airline pilots. While this episode is naturally focused on six-lever Twins, there is still value for FADEC (only) pilots. One specific question that comes to mind, as it relates to this thread and interview is:

What is the maximum AGL altitude you would chop power on takeoff and land straight ahead? And for all, or some, of the various DA42 models / engines vs. the DA62?

This former C-130 pilot, now giving MEI instruction in a Beech Travel Air, uses this rule (for this make and model):

Anything “less than 500’ AGL” he is going to react as if he were flying a single-engine and land straight ahead (20 degrees, left or right of the nose). Regardless of loading and density altitude. ..........

At 45:55 he specifys his engine failure "....at less than 500' AGL" comment to "....in my Travel Air". Looking at the Travel AIr's "specs" with only a 4400'MSL max single engine service ceiling as well as 2 180HP engines and its "boxy" aerodynamic shape, I'm guessing it does not have much (if any) single engine climb performance! So, treating it like a "single engine" airplane with an engine failure after takeoff makes sense!

When we had our DA42TDi (N742SA) and were doing ME instruction with it, typically we would give an engine failure after takeoff at 400'AGL (min altitude recommended by FAA) and at "blue line". For the most part, this was a "non-event" even for a "no time" multi engine student (make sure you guard against them applying incorrect rudder and that they put in correct rudder!) . 42TDi was operated at approx 3-400# below max gross for these flights.

DA42VI and DA62 are even more capable, once "clean".

Depending on how proficient someone is (AND the aircraft's gross wt AND the density altitude) - my best guess woud be 50-200'AGL, with airspeed at "blue line" for the DA42VI and 62. (see my previous post and especially depending on how long it takes to get over the "startle effect" of the engine failure)

So, long story short - his comment about 500'AGL pertains to ".....in my Travel Air....", not our twin diamonds!

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

Posted: Mon Sep 30, 2019 8:28 pm
by TwinStarScott
If an engine quits during takeoff, go and hold 6 deg pitch and then carefully go through PPAA (power, performance, analyze, action).
I would add Jan:

pitch to blue line* first and then note and hold the degree of pitch that airspeed provides on the attitude indicator.

Also, back when John Weber was providing technical support for the TDI fleet, I remember him telling me it was good practice to perform a feather test on each engine every month or so. Which is performed typically at the conclusion of a flight, while safely on the ground.

* or slightly above, but never below - blue line. This is why vortex generators make a safe airplane even safer - and especially on every takeoff, since they:

1) provide an additional airspeed cushion against the dreaded VMC roll, as they decrease VMC by 9 knots.
2) increase the rate of climb by 150 FPM
3) improve controllability

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

Posted: Mon Sep 30, 2019 9:26 pm
by Colin
How does one perform a feathering test?

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

Posted: Mon Sep 30, 2019 11:10 pm
by TwinStarScott
It's described in the maintenance manual, and the checklist (easier to read version) for this procedure is on pages 207-208 / Chapter 61-20-00

4. Propeller Un-Feathering Test
Detail Steps/Work Items Key Items/References
WARNING: DO NOT LET PERSONS INTO THE SAFETY RANGE OF THE
AIRPLANE. PROPELLERS CAN CAUSE INJURY OR DEATH.
(1) Position the airplane on level ground. Make sure
that:
S There are no loose stones on the ground
near the propeller.
S The safety zone around the airplane is clear.
S The airplane heads into the wind.
(2) Put chocks in front of each main wheel.
(3) Set the parking brake to ON.
(4) Make sure that the ENGINE FUEL SELECTOR
is set to ON for both engines.
(5) Make sure that the passenger door is closed
and locked. Close and lock the canopy.
(6) Set both engine power levers to 0%. Make sure that the power levers are free
to move.
(7) Set the ELECT. MASTER key switch to ON.
(8) Set the alternate air control to OFF.
(9) Make sure the area of the propellers is clear.
(10) Set the related ENGINE MASTER switch to ON.
(11) Make sure that the engine instruments read
correctly.
The RPM, LOAD and FUEL FLOW
indications must be zero (0). Dashes (-)
indicate a malfunction.
AIRCRAFT
Propeller DA 42 Series
AMM
Detail Steps/Work Items Key Items/References
Page 208
01 Jun 2017 61-20-00 Doc # 7.02.01
Rev. 4
(12) Turn the START key switch to the LH or RH
position as required.
Do not start the engine as long as the
white GLOW status light is illuminated.
(13) When the selected engine starts:
Release the START key switch.
(14) Leave the power lever at 0%. Make sure that there are no warning
lights on.
(15) Monitor the oil pressure. The oil pressure must rise to 1 bar
minimum, within 3 seconds of starting
the engine. If it does not, then you must
shut-down the engine.
(16) Let the engine idle at 890 RPM for 2 minutes. Monitor the engine instruments for
unusual indications.
(17) Set the power lever to give a speed frequency
of 1500 RPM.
(18) Shut off the engine by setting the related
ENGINE MASTER switch to OFF.
The engine must stop. The propeller
must feather (´ feathered position: 81°)
(19) Reset the ENGINE MASTER switch to ON. Do not start the engine.
(20) Observe the change in propeller pitch angle. The propeller must un-feather within
12 to 15 sec (´ low pitch: 12°).
Check the functional efficiency of the
accumulator if the propeller does not unfeather.
(21) Set the ENGINE MASTER switch to OFF. The propeller must remain in the unfeathered position. There is just a small
change in pitch angle of 3° (´ start lock
position: 15°)
Check the functional efficiency of the
accumulator if the propeller does not
remain in the un-feathered position.
(22) Set both engine power levers to 0%.
(23) Redo steps 9 thru 22 for the other engine.
(24) Set the ELECT. MASTER switch to OFF.