Loss of airspeed indicator on dual GI 275 install on a night takeoff in a Mooney Ovation

[Fly_M20R]

 

[aviatoreb]

Nice video.

I have a AoA indicator that has its own separate pressure tap on the other wing, that I figure could carry on to make up for a bad airspeed indication in such a situation.

[Davidv]

Don't feel too bad, I was guilty of exactly the same thing about a year ago with the same pitot cover (and even paint scheme!). It sounds great in theory to abort when you realize airspeed isn't working correctly but since the Mooney only flies when it wants to fly, I rely less on reaching a specific speed and more on feel to get off the runway.  Given the soft cover, like you, I glanced at it when I started my roll to confirm it was alive and then turned my attention to the engine instruments and outside the cockpit.  These serve as valuable lessons to NEVER skip a final walk around.  In my case, I was distracted because a water main had just broken right outside my hangar and there was mud everywhere.  It interrupted my normal flow and that's all that it takes.

[aviatoreb]

This gives me pause and reminds me the danger of forgetting something like a gust lock which clamps  controls..  I don't think in Mooneys we have them clamping on the wing, but only inside the airplane at the pilots post where it is impossible to miss, but still in other makes and models forgetting gust locks has lead to more than one crash.

[aviatoreb]

Thanks for the honest mea-culpa soul search video.  Modeling this kind of example of self critique is as important as the specific self-error you are sharing.

[tmo]

11 minutes ago, aviatoreb said:

Thanks for the honest mea-culpa soul search video.  Modeling this kind of example of self critique is as important as the specific self-error you are sharing.

This, three times. Thanks for this and all your other videos.

[Fly_M20R]

2 hours ago, aviatoreb said:

Nice video.

I have a AoA indicator that has its own separate pressure tap on the other wing, that I figure could carry on to make up for a bad airspeed indication in such a situation.

That's a great idea and investment!!

[Fly_M20R]

1 hour ago, Davidv said:

Don't feel too bad, I was guilty of exactly the same thing about a year ago with the same pitot cover (and even paint scheme!). It sounds great in theory to abort when you realize airspeed isn't working correctly but since the Mooney only flies when it wants to fly, I rely less on reaching a specific speed and more on feel to get off the runway.  Given the soft cover, like you, I glanced at it when I started my roll to confirm it was alive and then turned my attention to the engine instruments and outside the cockpit.  These serve as valuable lessons to NEVER skip a final walk around.  In my case, I was distracted because a water main had just broken right outside my hangar and there was mud everywhere.  It interrupted my normal flow and that's all that it takes.

Mooneys definitely take off when they want to and quite fast if light. I am sure that you were also quite upset, mainly at yourself, as me when you realized what happened. We get distracted and at times somewhat complacent and need to be better self-aware which is not always easy to do. 

Thanks for your comment.

[Fly_M20R]

49 minutes ago, aviatoreb said:

Thanks for the honest mea-culpa soul search video.  Modeling this kind of example of self critique is as important as the specific self-error you are sharing.

You are welcome! We learn from our errors as well as others. It is waaay better to learn from others!!  

[smwash02]

I made the same mistake in my C shortly after I bought it -- was easier to see when the cover was on in the Cessna I had before.

With an analog gauge and the same pitot tube cover I had airspeed come alive normally as I can remember and as soon as I rotated it went to 0 for the rest of the flight (day, CAVU). The flag got pretty battered, though. I used the AWOS winds and GS to compute a rough airspeed for gear and flaps.

Glad it all turned out well for you!

[aviatoreb]

15 minutes ago, Fly_M20R said:

That's a great idea and investment!!

I have an alpha system AoA indicator - by alpha systems - I initially got it several years ago to generally improve my landings, and to help back check me in all phases of flight for safety.  So I got it with an audible voice alert that says "getting slow" in English if you are approaching critical angle of attack - which I figured would be really good to know if that is happening in the pattern especially at that all important base to final turn.  It also helps for more accurate speed control at various weights.  Plus its on the very end of my glare shield so I have eyes entirely outside the cockpit looking down the runway when on late final and I can easily see how many lights and which colors are lit while focused at infinity down the runway - instead of either inside the cockpit or back and forth with eyes trying to focus near then far then near then far.

But - I soon realized it has at least two other major benefits. One I mentioned, which is it is truly a backup for a failed air speed indicator.  It has a separate probe under the right wing and separate plumbing.  There are several other brands available that measure directly aoa, as opposed to inferred angle of attack by some of the smart screens such as aspen, etc.

Mine is heated.  There is a benefit actually as an early warning for ice encounters since the probe itself is very pointy, and as we know ice likes to accumulate earliest on pointy objects.  So if I do not turn on the heat to the probe and then ice gets on the probe - which has happened before I have seen any ice on any other surfaces, then the aoa system becomes blocked and it thinks I am stalling and it says "getting slow" on my headset - so then I know to do something about it asap - get out of ice now and turn on aoa heat, turn on tks, etc.

E

[flyboy0681]

As I can attest, some things you only do once.

My GI-275 AI installation is currently near completion, but retains the six pack.

[Fly_M20R]

1 hour ago, aviatoreb said:

I have an alpha system AoA indicator - by alpha systems - I initially got it several years ago to generally improve my landings, and to help back check me in all phases of flight for safety.  So I got it with an audible voice alert that says "getting slow" in English if you are approaching critical angle of attack - which I figured would be really good to know if that is happening in the pattern especially at that all important base to final turn.  It also helps for more accurate speed control at various weights.  Plus its on the very end of my glare shield so I have eyes entirely outside the cockpit looking down the runway when on late final and I can easily see how many lights and which colors are lit while focused at infinity down the runway - instead of either inside the cockpit or back and forth with eyes trying to focus near then far then near then far.

But - I soon realized it has at least two other major benefits. One I mentioned, which is it is truly a backup for a failed air speed indicator.  It has a separate probe under the right wing and separate plumbing.  There are several other brands available that measure directly aoa, as opposed to inferred angle of attack by some of the smart screens such as aspen, etc.

Mine is heated.  There is a benefit actually as an early warning for ice encounters since the probe itself is very pointy, and as we know ice likes to accumulate earliest on pointy objects.  So if I do not turn on the heat to the probe and then ice gets on the probe - which has happened before I have seen any ice on any other surfaces, then the aoa system becomes blocked and it thinks I am stalling and it says "getting slow" on my headset - so then I know to do something about it asap - get out of ice now and turn on aoa heat, turn on tks, etc.

E

Thanks for the great overview and insight into you AoA unit. Been thinking about putting one in but haven't moved on it yet.

If I recall correctly the unit you have will also have the AoA vary as a function of flap setting, if you choose that option when installed. That is even more helpful. 

There is a company that sells a vane type unit which doesn't depend on pressure differentials as the AoA does. Any thoughts on that one? Can't offhand remember the name of it.

[Fly_M20R]

31 minutes ago, flyboy0681 said:

As I can attest, some things you only do once.

My GI-275 AI installation is currently near completion, but retains the six pack.

Yep, once is enough although some people have admitted at being repeat offenders... hahahaha!!!

Edited December 3, 2020 by Fly_M20R
Misspelling

[aviatoreb]

46 minutes ago, Fly_M20R said:

Thanks for the great overview and insight into you AoA unit. Been thinking about putting one in but haven't moved on it yet.

If I recall correctly the unit you have will also have the AoA vary as a function of flap setting, if you choose that option when installed. That is even more helpful. 

There is a company that sells a vane type unit which doesn't depend on pressure differentials as the AoA does. Any thoughts on that one? Can't offhand remember the name of it.

The vane one, cy100 is it?, seems like an excellent unit and less costly to install so I have nothing bad to say about it.  But it was not available when I was choosing and in any case I have two important features which would have caused me to choose what I.  1) I really like audible voice alerts (I also had installed separately a p2 audio system that voice alerts my gear situation just in case) - I think there are too many bells and whistles to remember which is which in the heat of the moment if you really need to be warned.  "Getting slow" really tells you what is happening in a way you process immediately, and it is really nice to hear when you are 18 inches over the runway.  As far as I know the alpha system is the only one with voice alerts.  In any case some kind of audible alarm whether voice or even a bell is better than just a display since you need to be remembering to looking at the display - think of an error during base to final turn - will you be looking at a needle just while you are making a mistake?  knock on wood - and of course the ability to mount the indicator in line of site for use during flare.  2) I really like the heated probe.  In particular the cy100 doesn't have that and I don't think any others do.  Also, The cy100 seems to be a bit larger and could it impact cruise speed?  Also, whatever we choose, 

[Fly_M20R]

16 minutes ago, aviatoreb said:

The vane one, cy100 is it?, seems like an excellent unit and less costly to install so I have nothing bad to say about it.  But it was not available when I was choosing and in any case I have two important features which would have caused me to choose what I.  1) I really like audible voice alerts (I also had installed separately a p2 audio system that voice alerts my gear situation just in case) - I think there are too many bells and whistles to remember which is which in the heat of the moment if you really need to be warned.  "Getting slow" really tells you what is happening in a way you process immediately, and it is really nice to hear when you are 18 inches over the runway.  As far as I know the alpha system is the only one with voice alerts.  In any case some kind of audible alarm whether voice or even a bell is better than just a display since you need to be remembering to looking at the display - think of an error during base to final turn - will you be looking at a needle just while you are making a mistake?  knock on wood - and of course the ability to mount the indicator in line of site for use during flare.  2) I really like the heated probe.  In particular the cy100 doesn't have that and I don't think any others do.  Also, The cy100 seems to be a bit larger and could it impact cruise speed?  Also, whatever we choose, 

Perfect reasoning!

[Flyphilly]

9 hours ago, aviatoreb said:

I have an alpha system AoA indicator - by alpha systems - I initially got it several years ago to generally improve my landings, and to help back check me in all phases of flight for safety.  So I got it with an audible voice alert that says "getting slow" in English if you are approaching critical angle of attack - which I figured would be really good to know if that is happening in the pattern especially at that all important base to final turn.  It also helps for more accurate speed control at various weights.  Plus its on the very end of my glare shield so I have eyes entirely outside the cockpit looking down the runway when on late final and I can easily see how many lights and which colors are lit while focused at infinity down the runway - instead of either inside the cockpit or back and forth with eyes trying to focus near then far then near then far.

But - I soon realized it has at least two other major benefits. One I mentioned, which is it is truly a backup for a failed air speed indicator.  It has a separate probe under the right wing and separate plumbing.  There are several other brands available that measure directly aoa, as opposed to inferred angle of attack by some of the smart screens such as aspen, etc.

Mine is heated.  There is a benefit actually as an early warning for ice encounters since the probe itself is very pointy, and as we know ice likes to accumulate earliest on pointy objects.  So if I do not turn on the heat to the probe and then ice gets on the probe - which has happened before I have seen any ice on any other surfaces, then the aoa system becomes blocked and it thinks I am stalling and it says "getting slow" on my headset - so then I know to do something about it asap - get out of ice now and turn on aoa heat, turn on tks, etc.

E

I am curious about this- do you think any avionics shop can put one in? What was the approximate cost all in?

[aviatoreb]

5 minutes ago, Flyphilly said:

I am curious about this- do you think any avionics shop can put one in? What was the approximate cost all in?

I think any avionics shop can do the job.  I certainly had a general avionics shop do it.  Actually I think it has an entirely independent plumbing system, so in principle I think a not avionics but general AP could do the job.

It was 7 or 8 years ago so I don't remember the cost but it was not trivial since there is a probe to mount on the wing, plumbing to lead to the wing, and also electric for the heated probe and electric to tap into the audio system.   I would guesstimate and with fuzzy memory something like 2k beyond the parts cost.  It is a fantastic system and I enjoy it every time I fly with confidence I am on speed for the conditions of the day.

[carusoam]

CYA-100

https://www.aircraftspruce.com/catalog/inpages/aoacya100.php

For additional info about AOAi(s) we have a few suppliers in one thread that discusses the various sensors and systems...

Oddly, I saw CK’s video in YouTube... before getting here today... 

What is surprising to me... we are usually satisfied with ‘Airspeed alive!’ to continue on....

This ASI gave an indication (erroneous) of 23kias... enough to see and move on to next steps...

We might want to ask our Garmin guy to see if Big G has something to keep from getting an erroneous signal... kind of a safety issue... they may want to consider...

Other tools we use for speed...

1) back-up ASI...

2) AOAi

3) GPS ground speed

4) Lastly, Stall warning system...

5) Setting speed using power, configuration, attitude...

It was a great landing!  

Best regards,

-a-

[Fly_M20R]

22 hours ago, carusoam said:

What is surprising to me... we are usually satisfied with ‘Airspeed alive!’ to continue on....

This ASI gave an indication (erroneous) of 23kias... enough to see and move on to next steps...

We might want to ask our Garmin guy to see if Big G has something to keep from getting an erroneous signal... kind of a safety issue... they may want to consider...

Other tools we use for speed...

1) back-up ASI...

2) AOAi

3) GPS ground speed

4) Lastly, Stall warning system...

5) Setting speed using power, configuration, attitude...

It was a great landing!  

Best regards,

-a-

Yes, what made me think that airspeed was alive is because in all other takeoffs (those with pitot cover off ) it ALWAYS goes straight from 0 to 23, nothing in between. Not sure why it does so in normal conditions or why it did w the cover on. (???).

My backup ASI is the second GI 275 which is why I flipped to that page on it and found same reading as top one. It does share the same pitot-static plumbing as the top one and so would any additional analog/mechanical ASI, at least in GA planes. An AoA as aviatoreb has does have separate plumbing and therefore definitely useful. Just remember to remove cover before flight, if it has one. 

I now wait till I see the ASI continue moving up and read at least 40 before really calling it alive.

In addition, as an experiment I plan to do a brief takeoff and immediate landing on a looong runway with all of the pitot tube very well covered (ram intake and drain hole) and record what happens.

As an aside, in spite of the erroneous initial 23 kt reading Garmin's 275 stayed functional in all other readings without the airspeed input. Aspen units will "red-X" everything without airspeed input. Supposedly got that fixed on the Promax version. Not sure what Dynon, King or other units do. 

Thank you for your always insightful comments carusoam!

Edited December 5, 2020 by Fly_M20R
clean up

[carusoam]

@KLudwick An interesting Garmin challenge has arisen...

GI275 indicates speed enough for a pilot to think it is working properly, when it isn’t...

 

@Baker Avionics This may be of interest to you as an avionics guy...

Essentially...

1) When a pitot cover is left on...

2) Most pilots verify the ASI is operational during the T/O roll early...

3) They assume once it is reading... it is going to be correct.

4) In the case of this instrument... something has it come alive, give a reading of 23KiAS...

5) Enough to distract the pilot thinking all is go... continue with the T/O...

6) Essentially a false indication is displayed... the pilot was lead to believe the ASI was working when it wasn’t

It looks like something can be improved to identify and not display the false reading...

Please share this with your contacts within Garmin...

PP thoughts only, sharing an observation made by the Garmin user...

Best regards,

-a-

 

[KLudwick]

Thanks for the tag, @carusoam.  

@Fly_M20R, thanks for highlighting your new GI 275's in your newest videos!  Out of curiosity, have you talked to your dealer/installer about this yet?

[Fly_M20R]

20 hours ago, KLudwick said:

Thanks for the tag, @carusoam.  

@Fly_M20R, thanks for highlighting your new GI 275's in your newest videos!  Out of curiosity, have you talked to your dealer/installer about this yet?

Hi KLudwick,

Yes, I did talk with the installer/dealer. They are not clear as to why the ASI "came alive" when covered. It is either due to some ram air getting around the cover since it is not very tight fitting or could be how Garmin uses Ground speed to correlate with valid indicated airspeed. I believe the best ones to contact would be Garmin. However, have not had sufficient time to do so yet. I do plan to do a test "flight" on a quite long runway to give me room for a brief takeoff and land right away with the pitot cover well sealed, including the drain hole in the back of it. I shall report back with a video when I have done this. May be a few weeks...

Regards,

CK

[hypertech]

Sometimes I wonder if there would be a market for a pitot tube cover with a little parachute so it rips off if someone forgets.  

[Fly_M20R]

19 minutes ago, hypertech said:

Sometimes I wonder if there would be a market for a pitot tube cover with a little parachute so it rips off if someone forgets.  

Hahahahahaha!!! Great idea!!  A friend has left his on a few times and he says it shreds away.... I'll have to ask him what brand it is.