six gear collapses & gear ups in one week

[brndiar]

6 hours ago, kortopates said:

Here is chart of glide ratios of several aircraft that I use in my class. But for comparison, the Mooney's have excellent glide ratios. Not sure what aircraft stand above others but I imagine a DA20 would do well too.

Interesting, thanks for that.

I know, we are of the initial topic (gear up landing), but for me it is safety issue too because with less than speed for best glide we are entering back side of the power curve.

It would be practical to know best glide speed numbers for gear down,  T/O and full flaps situations (+idle RPM).

m.

 

[ArtVandelay]

Here is chart of glide ratios of several aircraft that I use in my class. But for comparison, the Mooney's have excellent glide ratios. Not sure what aircraft stand above others but I imagine a DA20 would do well too.

I would expect the J and K to be the same given they are same body type?

[kortopates]

11 hours ago, ArtVandelay said:

I would expect the J and K to be the same given they are same body type?

I agree! But they are not! interesting isn't it? Could it just be variation or error in collecting the data? I can't say but probably doubtful. Interestingly the R is identical to the J but the K beets them both. Since Vg is lift/drag its got to be due to some differences in drag between each of the models and we know cowling is a significant source of drag. Plus we know weight doesn't change the glide ratio at all, just the speed for Vg. Its an interesting question I have wondered myself.

Edited May 16, 2020 by kortopates

[kortopates]

12 hours ago, brndiar said:

It would be practical to know best glide speed numbers for gear down,  T/O and full flaps situations (+idle RPM).

I don't honestly think that Vg applies to anything other than a clean configuration. After all, if we need to glide to an airport we MUST clean up the airframe unless to improve our range: Gear up, flaps up, Prop back. Much more important to the making the airport is adjusting Best glide for the wind. With a headwind, as would often be the case on final landing into the wind, you'd want to increase you IAS to help make up for the headwind and slow down in tail wind.

Once we get to the airport gear down and Vg is no longer relevant, now Min Sink is which gives us more time to spiral down and/or setup to landing.

But the only time a dirty best glide would have relevance IMO is when you have an equipment failure of some kind - such as you can't raise the gear or flaps. In that case you'd find the dirty configuration with the same glide ratio is going to decrease your best glide speed for the same weight while also decreasing your glide range. Without collecting the data yourself, some of the best insights can be gleamed from POH data by comparing otherwise identical airframe variants between the fixed gear model and the retractable gear model. For example, since you fly a C, you could get a very good idea by comparing what the unmodified D model best glide was but without identical draggy gear doors assume yours is even slower gear down.

[Schllc]

My first mooney instructor, when I was a 40hr ppl and preparing to buy my plane taught me the three mile 900’ rule on final. 300’ per mile descent keeps you perfectly set, and you control altitude with throttle  

this won’t work in a long body with the gear up unless you slow down to 80 knots before you enter the pattern. It’s impossible to bleed speed Fast enough on final this way if the gear is up. 
With (so far) 600 mooney hours ive, thankfully never come close to a gear up because the speeds don’t jive with my procedure. I only have a few hours in a mid body k, but found it to be as slippery as an ovation or acclaim in that phase of flight. 
I honestly don’t understand how one could forget because the darn thing just won’t get to landing speed with the gear up. 
I hope that doesn’t sound cocky, I mean I’ve made my share of mistakes too, just not that one, and I believe it’s because the plane acts really weird to me with the gear up. 
if something “feels” wrong about an approach, there usually is something wrong.

I try to listen to that, and hope I always do. 

[ArtVandelay]

I agree! But they are not! interesting isn't it? Could it just be variation or error in collecting the data? I can't say but probably doubtful. Interestingly the R is identical to the J but the K beets them both. Since Vg is lift/drag its got to be due to some differences in drag between each of the models and we know cowling is a significant source of drag. Plus we know weight doesn't change the glide ratio at all, just the speed for Vg. Its an interesting question I have wondered myself.

Propellor differences?

[pwhicks]

In addition to high headwind scenarios.

It would be pretty easy to stay slow enough to forget the gear when staying in the pattern practicing landings or after a go around.

Our J never really gets above 120mph in that scenario as I’m having to back of the throttle to stop climbing.

It is also the only scenario (so far #KnockOnWood) that I caught myself not descending correctly and realized I missed it on the downwind.

When I’m coming in to an airport visually from cruise speeds, my first step is to slow down over the top or from the diagonal (usually having to climb slightly) and drop the gear to try to get slowed towards flap speeds.

With instrument approaches, I don’t find the same conditions and potential issue since I’ve stabilized my settings miles from the airport and am waiting to throw my gear to catch the glide slope.

I’d be interested to see what % of gear ups are during visual conditions.


Sent from my iPad using Tapatalk

[Oscar Avalle]

On 5/12/2020 at 1:16 PM, Bob - S50 said:

From what seems like a couple lifetimes ago in the Air Force, at least in trainers and fighters (don't know about big airplanes), we always had to make a radio call that included 'gear down'.  Something like "Auburn traffic, Mooney 1CB, left base 34, gear down, full stop, Auburn traffic."

Maybe verbalizing it to the world might help just a little.  And on the rare occasion when we are holding short of the runway, we can help each other by confirming an aircraft on final has wheels down and say something if they don't.

GUMPS check saying it out loud and touching the, GAS, Gear, Mixture and Prop handles/levers is how I try to minimize the chance of forgetting it.

[Andy95W]

39 minutes ago, Oscar Avalle said:

GUMPS check saying it out loud and touching the, GAS, Gear, Mixture and Prop handles/levers is how I try to minimize the chance of forgetting it.

I'm with Oscar, and I add a couple of fail-safe backstops, just in case.  Even if I miss one of them, so far I haven't missed both.

-My Garmin tells me "500".  When it does, I read back to it, "500, green light" as I point at the green light.

-On short final, when I can clearly see the runway numbers, I say out loud, "Got the numbers, got a green light" as I point at the numbers and point at the green light.  This is also my double check that I'm landing on the correct runway.

[kortopates]

On 5/15/2020 at 7:28 AM, Bob - S50 said:

All I can say is try it.  Stay clean, pull the power but not so much that the horn comes on and try to track an ILS or LPV glideslope.  See what your speed is after 1000' of descent.

I did get to try this once over the weekend. I slowed to 120 IAS  before descending clean but I am sorry to say I missed your statement of "not so much that the horn comes on" since I definitely had the horn on to descend.  I waited to to late,  but I'll experiment a bit more out of curiosity to see if allowing the aircraft to slow down closer to pattern speeds  if that would help as a better setup to enable a descent of 1000' without the horn coming on. But we all know, cause we've seen the videos, that even 2 busy distracted pilots have ignored the horn to land gear up.

I do think the vast majority of these occur in the pattern. Everyone that's I've  ever heard about was due to distractions and often some out of the ordinary change from their regular pattern. Its got to much harder to land gear up on an instrument approach, not only because of the horn but because most of us use the gear to descend past the FAF or on GS and still have several minutes to catch it - or maybe hear the horn - before landing.

After all, Mooney pilots continue to do this every weekend on average if not more and  although they could all be ignoring the horn - I doubt it and that simply there horns aren't working. At least this past weekend no new reported Mooney gear ups!    

[Bob - S50]

2 hours ago, kortopates said:

I did get to try this once over the weekend. I slowed to 120 IAS  before descending clean but I am sorry to say I missed your statement of "not so much that the horn comes on" since I definitely had the horn on to descend.  I waited to to late,  but I'll experiment a bit more out of curiosity to see if allowing the aircraft to slow down closer to pattern speeds  if that would help as a better setup to enable a descent of 1000' without the horn coming on. But we all know, cause we've seen the videos, that even 2 busy distracted pilots have ignored the horn to land gear up.

I do think the vast majority of these occur in the pattern. Everyone that's I've  ever heard about was due to distractions and often some out of the ordinary change from their regular pattern. Its got to much harder to land gear up on an instrument approach, not only because of the horn but because most of us use the gear to descend past the FAF or on GS and still have several minutes to catch it - or maybe hear the horn - before landing.

After all, Mooney pilots continue to do this every weekend on average if not more and  although they could all be ignoring the horn - I doubt it and that simply there horns aren't working. At least this past weekend no new reported Mooney gear ups!    

As Billy Joel said (kind of), "We're only human, we're allowed to make mistakes."  In the safety world, the least effective way to stop a mishap from happening again was to establish a procedure to be followed by humans.

So, yes, I agree, even the gear horn going off won't stop us from landing gear up.  However, my personal philosophy is that, under normal conditions, if the horn is going off I need to either push up the power to extinguish it or I need to put the gear down.  The LAST thing I want to do is drive merrily along with the gear horn blaring in my ear.  Not because it's annoying, but because we become habituated to the noise and it no longer is an effective warning.  I would encourage anybody who routinely flies with the horn blasting away for extended periods to change their habits.

As to the speed on glidepath.  For my airplane, clean and the power back to about 13 inches will give me about 100 KIAS.  That's faster then best glide which in turn is faster than minimum drag.  So if I'm doing that level, and then lower the nose to track the glideslope, my speed will increase.  And I've found that in still air, a descent of about 200'/NM will give me about 120KIAS which is below gear speed but above flap speed.  300'/NM, clean, and just above the horn gives my something around 130 or 135 which is flirting with too fast to lower the gear.  And that speed would also make me a category C aircraft for the approach until I slow down.

[1001001]

As far as gear collapses go, make sure your gear actuator has been checked properly.  I bought a '78 J model last year and during the pre-buy the guys caught a bad actuator.  At first they thought it might be the position switches since they were getting an intermittent gear unsafe light during the runup test.   After putting the airplane back up on jacks and re-swinging the gear they determined the clutch was not preventing a reverse motion.  Sent it out to LASAR for overhaul and the internal condition of the gear drive (not just the clutch) was found to be atrocious.  All involved estimated that it was only a matter of a short time before that actuator would have either failed in operation or allowed the gear to retract on the ground during landing or in a turn.

[carusoam]

Great words about the power and value of a PPI...

1001001, who did the PPI for you?

Best regards,

-a-

[1001001]

8 minutes ago, carusoam said:

Great words about the power and value of a PPI...

1001001, who did the PPI for you?

Best regards,

-a-

I had it done by a local shop at KBVI that has a well deserved reputation for extreme thoroughness.  They used the LASAR checklist as a basis for their work.

[carusoam]

+1 for the quality of the people holding the tools....not always the name on the shop...  

Thanks,

-a-

[philiplane]

And, now we add three more in the past week. M20C gear collapse in CA on the 20th,  a Bravo prop strike in Nevada on the 22nd, and an M20K runway over-run with nose gear collapse on the 25th in CA. 

[N9201A]

I agree! But they are not! interesting isn't it? Could it just be variation or error in collecting the data? I can't say but probably doubtful. Interestingly the R is identical to the J but the K beets them both. Since Vg is lift/drag its got to be due to some differences in drag between each of the models and we know cowling is a significant source of drag. Plus we know weight doesn't change the glide ratio at all, just the speed for Vg. Its an interesting question I have wondered myself.

Have you ruled out that the K number is “prop stopped” and the J is “windmilling”?

[mike_elliott]

On 5/15/2020 at 6:02 PM, kortopates said:

Here is chart of glide ratios of several aircraft that I use in my class. But for comparison, the Mooney's have excellent glide ratios. Not sure what aircraft stand above others but I imagine a DA20 would do well too.

Paul, any idea why the heavier K with the same airframe and perhaps more parasitic drag as a J would have a better glide ratio?

[Steve W]

On 5/14/2020 at 9:48 AM, HRM said:

What's the penalty for having a GU?

Apparently the insurance companies aren't putting enough pain into it, or the pilots are departing GA afterwards.

Mine was about 10% additional premium 2 years ago(and then 10%, and then 10% again)

 

I'd sure have rather had a working plane than the insurance check 2 years later, provided it arrives one of these days.

[carusoam]

15 hours ago, mike_elliott said:

Paul, any idea why the heavier K with the same airframe and perhaps more parasitic drag as a J would have a better glide ratio?

Glide ratio physics is interesting...

As we found the P51 was pretty similar to a Mooney...

From April’s discussion... it’s a long discussion... find the April part.... or search for P51... 

Best regards,

-a-
 

 

[kortopates]

On 5/26/2020 at 8:25 AM, N9201A said:

Have you ruled out that the K number is “prop stopped” and the J is “windmilling”?

I don't recall seeing Mooney publish "prop stopped" best glide performance since the 60's for the M20C. To the best if my recollection, everything since has been windmilling only.

On 5/26/2020 at 9:30 AM, mike_elliott said:

Paul, any idea why the heavier K with the same airframe and perhaps more parasitic drag as a J would have a better glide ratio?

Not really, at least no engineering data to explain it, but the key differences are cowling, prop, wing tips and landing gear doors. I doubt the last two are significant and assumed it's most likely explained more from the first two. We know weight doesn't effect it, weight only affects Best glide speed.

Of course best glide ratios from the POH are no longer any good once someone installs a different STC prop; especially going from a 2 blade to a 3-blade. But good luck finding any glide ratio data with the prop STC information. 

[Ibra]

11 hours ago, kortopates said:

Not really, at least no engineering data to explain it, but the key differences are cowling, prop, wing tips and landing gear doors. I doubt the last two are significant and assumed it's most likely explained more from the first two. We know weight doesn't effect it, weight only affects Best glide speed.

Of course best glide ratios from the POH are no longer any good once someone installs a different STC prop; especially going from a 2 blade to a 3-blade. But good luck finding any glide ratio data with the prop STC information. 

Yes seems mainly the long and sleek engine cowling on the +231
On L/D data one is better flying at various IAS and get VSI on idle power, add 100fpm to VSI & round it
Then figure out glide ratio & glide speeds and add few kts depending on weight & wind 

[mike_elliott]

12 hours ago, kortopates said:

I don't recall seeing Mooney publish "prop stopped" best glide performance since the 60's for the M20C. To the best if my recollection, everything since has been windmilling only.

Not really, at least no engineering data to explain it, but the key differences are cowling, prop, wing tips and landing gear doors. I doubt the last two are significant and assumed it's most likely explained more from the first two. We know weight doesn't effect it, weight only affects Best glide speed.

Of course best glide ratios from the POH are no longer any good once someone installs a different STC prop; especially going from a 2 blade to a 3-blade. But good luck finding any glide ratio data with the prop STC information. 

I just sent Bob K a note to see if his engineering notes would enlighten exactly why...standby....

...and here is his answer

Mike,

I believe it’s because the idle power (and prop windmilling) prop disc drag of the K is a bit less that the J.  All due to aerodynamics of the prop blade twist and cross-section differences near the hub at low and no power conditions.  I don’t have drag polar data to prove this, but I do remember seeing these comparative polars while at the factory.

 

Bob

[philiplane]

So we're up to nine gear incidents in a little over two weeks time.

How exactly is the glide distance distraction helping us here? If the Mooney community wants affordable hull insurance next year, we're going to have to figure out what's happening, and stop doing it. I watched one M20J narrowly avoid a gear collapse yesterday. The pilot who shall remain nameless, was trying to force it onto the ground, and got into a pretty bad porpoise. He had the good sense to power up and go around after the third bounce. The fourth would have collapsed the nose gear. On the same runway at the same spot a previous M20J collapsed his gear back in January. That plane is still in the shop for repairs.

Edited May 28, 2020 by philiplane

[carusoam]

12 hours ago, philiplane said:

 

How exactly is the glide distance distraction helping us here?

is this a rhetorical question?

Or would you like a real answer?
 

Best regards,

-a-