Decending and Landing Mooney techniques

[fantom]

Correct....LOP/ROP.....use the red knob a little!

[Hank]

Quote: jetdriven

Yeah Hank I keep forgetting you are carb'd.  In that case do you keep it leaned to edge of smooth on descent?

[Shadrach]

Quote: Hank

 The higher I cruise, the closer to peak I run. On descent, I maintain cruise EGT [more or less] and cruise MP [more or less]. That ends us being lots of tweaks to those two levers. But then, I like having the quadrant rather than the push/pull/twist knobs.

[flyboy0681]

It sounds like a lot of people here are having trouble determining when to start coming down. Am I the only one that uses the Vertical Speed Required (VSR) feature on the GPS?

[DaV8or]

Quote: flyboy0681

It sounds like a lot of people here are having trouble determining when to start coming down. Am I the only one that uses the Vertical Speed Required (VSR) feature on the GPS?

[carusoam]

My favorite tool of my portable Garmin is when to start down,  VFR.

 

I typically target 400 fpm.

 

This is a good compromise of speed and safety.

 

Best regards,

 

-a-

[jlunseth]

I use it almost every trip, and definitely every time I go to the higher altitudes.  I have posted this before - I use the "tip the nose over" technique of descending from altitude, and that is going to mean a significant increase in GS during the descent, so I usually "lead" the descent a little, meaning if I want to descend at 500 fpm, I will start down when the Garmin says 480 is needed.  That will change quickly as GS increases.

Great tool to plan a descent.

[Jeff_S]

My rule of thumb is 5 miles for every 1000' feet of descent. Think about it; we cruise generally in the 150 knot range, most us (turbo and long body boys excluded) which is 2.5 miles per minute.  When we tip the nose over for descent we'll pick up some of that speed, but I generally see TAS of 165+/- in cruise descent. That's a bit closer to 3 miles/minute but I use 2.5 to be conservative. At 500 fpm descent, that's 2 minutes for every 1000', or 5 miles. Easy peasy lemon squeezy. (If you really do approach 180 KTAS, use 6 miles per 1000'.)

No GPS programming required and gets you into the ballpark without any undue stress on the engine. If winds or other conditions cause throw off the timing, I'll simply reduce RPMs to 2400 to slow down a skosh, or reduce VS to 400 fpm to stretch it out.

And being a dedicated LOPer, I don't touch the red knob at all, unless I have to spend any appreciable time at a lower altitude in which case I'll richen back to my target EGTs to keep the speed up.

[jetdriven]

To me 500 FPM is too shallow.  I use 750 FPM, 180 KTS G/S and 250 ft/mile.  Assumes WOTLOP. Thats 4 miles per thousand feet of altitude.  500 FPM is only 166 ft/mile.   Using the former, starting down from 10,500 to sea level is starting down 63 miles out.  Using 700 ft/min is 42 miles.  How much time do you want to spend bumping along sweating in the summer below 5000'?

[carusoam]

JetD,

 

I see your point...

 

A descent in the NE is planned differently than one in TX.  Very interesting.

 

In the NE, an AP has more value than AC.  In TX, it is probably the other way around?

 

How many days over 100dF have you seen this summer?

 

My slow 400fpm descents from 11,500 down to near SL start way out and barely gets me slowed down for pattern entry.  Air blowing through the cabin is still very comfortable.  Temp rise after touch down is quick and GPMS automatically actuates the door.

 

Best regards,

 

-a-

[Shadrach]

I use 3 miles per minute and ~1000FPM +/- 500 in descent depending on conditions and whether I'm alone (I don't mind clearing my ears repeatedly in descent but I'm mindful that passengers might.). I will reduce power to manage airspeed if necessary depending on conditions. I have no concerns about descending just under redline (~170kts), especially in the glass smooth evening air. I use the GPS descent profile function to make small adjustments. 

[jlunseth]

When you start at FL190 or 220, it is awhile before you get to the bumps.  And the descent is not from 68 out, its between 75 and 100 out, especially with a tail wind.  Fast ride though.  You can cover that last 100 miles in around a half hour in a pokey old 231. 

But truth be told I don't hold a perfect 500 fpm in my 231.  I use the AP to do these descents, and don't have a means of setting vertical speed other than establishing a pitch and MP.  This leads to a variable rate of descent, because the first thing that happens is that the plane picks up a fair amount of airspeed and therefore lift.  And as you go lower the air density changes as well.  Sometimes the VS creeps up to 300 when I am not watching, and sometimes I need to adjust it down to 800 or so to keep my descent plan intact.  And sometimes I miscalculate how long it is going to take to get down, or ATC comes on and says they want me at "x" altitude 20 miles further out than I had planned on, and I need to go to 1000 fpm or so to make it. 

My point is, the exact VS is not a very big deal.  But the Mooney is a slick, fast, high flying plane, whether turbo or normal aspirated.  So rather than using the "old school" descent technique of throttling back to 20" (for my turbo) and maybe deploying speedbrakes to slow down.  Make use of the energy you have stored by ascending to altitude and take the fast way home. 

[aviatoreb]

Quote: flyboy0681

It sounds like a lot of people here are having trouble determining when to start coming down. Am I the only one that uses the Vertical Speed Required (VSR) feature on the GPS?

[carusoam]

EB,

 

My simple Garmin portable can be programmed for height above airport and distance away.  No inflight calculations required.  I think my set points are 400fpm, 1,000ft above,  3 miles out.  My retro IFR GPS can set a descent angle (requires inflight calculation, I can't find a usefulness for this feature).

 

Garmin allows me to arrive at TPA a few miles out, in order to slow to proper speeds.

 

There are two other details that are helpful in this department.  There is a vertical timer that tells how much time is left before the nose over.  There is also a glide slope line that indicates if you are ahead or behind schedule.

 

Like JL points out above, variations in density, power output and speed will make it near impossible to set a vertical velocity and keep it there.  In VMC, you want to be looking outside, and not overly focused on the vertical speed.

 

In the past I did the calculations for 3 miles per minute and tried to maintain VV.  Conservative alt adjustments for engine failure. The end result was excessive speed in the traffic pattern.

 

Gps vertical guidance is an excellent aid to balance safety and efficiency while descending with maximum forward velocity.

 

Best regards,

 

-a-

[Shadrach]

Quote: carusoam

 

EB,

 

My simple Garmin portable can be programmed for height above airport and distance away.  No inflight calculations required.  I think my set points are 400fpm, 1,000ft above,  3 miles out.  My retro IFR GPS can set a descent angle (requires inflight calculation, I can't find a usefulness for this feature).

 

Garmin allows me to arrive at TPA a few miles out, in order to slow to proper speeds.

 

There are two other details that are helpful in this department.  There is a vertical timer that tells how much time is left before the nose over.  There is also a glide slope line that indicates if you are ahead or behind schedule.

 

Like JL points out above, variations in density, power output and speed will make it near impossible to set a vertical velocity and keep it there.  In VMC, you want to be looking outside, and not overly focused on the vertical speed.

 

In the past I did the calculations for 3 miles per minute and tried to maintain VV.  Conservative alt adjustments for engine failure. The end result was excessive speed in the traffic pattern.

 

Gps vertical guidance is an excellent aid to balance safety and efficiency while descending with maximum forward velocity.

 

Best regards,

 

-a-

 

[kortopates]

[carusoam]

Ross, 

Garmin 196.  For some reason Garmin still supports this one.  Where newer, more costly versions have fallen away.

 

I won't be getting weather or Synthetic Vision on it anytime soon, but it is a waas quality GPS back-up with vertical guidance.  It is also my preferred device for "nearest" ( airport, vor, atc, weather broadcast, etc.)

 

This device is also a great source for log book details.

 

Best regards,

 

-a-

[aviatoreb]

Quote: carusoam

 

>EB,

Nice of you to figure out that aviatoreb stands for EB - short for Erik Bollt btw.  Hello.

>My simple Garmin portable can be programmed for height above airport and distance away.  No inflight calculations required.  I think my set points are 400fpm, 1,000ft above,  3 miles out.  My retro IFR GPS can set a descent angle (requires inflight calculation, I can't find a usefulness for this feature).

Which model do you have?

I have an Aera now as my handheld/backup.  Actually, until recently I never even heard of VSR.  This is my first plane with WAAS gps - 430W - and I didn't even know there existed a VSR function until one day my CFI showed it to me.  I will look to see if I can configure my Aera to do as you describe.

>Garmin allows me to arrive at TPA a few miles out, in order to slow to proper speeds.

What does TPA stand for?

>Like JL points out above, variations in density, power output and speed will make it near impossible to set a vertical velocity and keep it there.  In VMC, you want to be looking outside, and not overly focused on the vertical speed.

Agreed regarding eyes outside in VMC.

This being my first turbo I am struck with one major difference as compared to decent in a normally aspirated which keeps gaining MAP as it descends thus decreasing decent rate and so requiring constant throttle decreasing to keep going down.  The turbo is nice as it maintains MAP going down as well as going up.

[aviatoreb]

[jetdriven]

Carousam:

there have been something like 20 days over 100 and the entire summer has been 95+.  Id rather fly through a thunderstorm than deal with the heat and turbulence below 5000'.  However, 300' per mile is too steep in a J. thats like 900 FPM.   Ours must have  a duct leak cause the front vents blow a small amount, the rear vents are a hurricane.

Quote: carusoam

 

JetD,

 

I see your point...

 

A descent in the NE is planned differently than one in TX.  Very interesting.

 

In the NE, an AP has more value than AC.  In TX, it is probably the other way around?

 

How many days over 100dF have you seen this summer?

 

My slow 400fpm descents from 11,500 down to near SL start way out and barely gets me slowed down for pattern entry.  Air blowing through the cabin is still very comfortable.  Temp rise after touch down is quick and GPMS automatically actuates the door.

 

Best regards,

 

-a-

 

[jetdriven]

do your 250' per mile cacluation then add ~4 miles for getting down, slowing down, and configuring. 

Quote: carusoam

 

In the past I did the calculations for 3 miles per minute and tried to maintain VV.  Conservative alt adjustments for engine failure. The end result was excessive speed in the traffic pattern.

 

Gps vertical guidance is an excellent aid to balance safety and efficiency while descending with maximum forward velocity.

 

Best regards,

 

-a-

 

[carusoam]

 

EB,

 

Erik,  nice to meet you.

 

My Garmin 196 is what I am using for vertical situational awareness.  Waas GPSs were the invention required to allow for vertical guidance.  I would expect any waas gps system from Garmin should have this capability.  Since my Garmin was the first waas system several years ago.  See above exchange with Ross.

 

TPA-traffic pattern altitude.  It is a standard acronym from somewhere....?

 

The Garmin guys at the time were very forward thinking and always gave the most functionality that could be used by pilots.  The 196 is feature rich, but easy enough to find all the features and decide how best to use them.

 

Since the 430W is built for IFR approaches with vertical guidance, I would expect more functionality, but it is up to the good people at Garmin to allow for it in their programming.  It is probably in there somewhere.

 

Since I am an amateur flyer with a single engine, it is my preference to stay as high as I can (without supplemental oxygen) until it is time to come down.  When it is time to come down, I want my stored energy back to somewhat balance my fuel usage in the climb.  The last thing I want to avoid is arrive over the airport too high or too fast or be too far out down low.  VNAV, as Garmin calls it,  is additional awareness to help optimize the situation.  The nice thing is it can be adjusted to meet you requirements.

 

For the guys who like 700fpm, no problem.  Standard training picks 500fpm, this works too.  400fpm works for me. I see high IAS, without going over VNE. Some throttle adjustment is required for the NA crowd.  The VS is jus a setting on the setup page.

 

The M20R sneaks up on VNE without much warning.  My M20C gave obvious signals she was going fast.

 

 

Best regards,

 

-a-  (Anthony)

 

[carusoam]

JetD,

 

I'm glad we had this exchange.  I need to reprogram to be at TPA further out.  I have been using three miles and being uncomfortably fast, dropping wheels, entering the pattern and getting down to target speed.

 

4 is probably right on the money.

 

Thanks,

 

-a-

 

[aviatoreb]

[jetdriven]

Im sure the 231 is like a 201 but more like a jet, if you are getting high and fast, shove it down first, level off then slow down.   Slowing down first the plane laughs at you.  I can hear mine laughing right now at me.... I have screwed it up pretty good the first few times.