Vacuum Failure Enroute to Florida

[MooneyBob]

13 minutes ago, aviatoreb said:

it seems perfectly stable - what you are looking at there is after w 45 min flight and the attitude is still good since start up.. it's with the gdl39-3D behind the window center post barely in view in the picture.. I have never seen it hiccup.

Do you reset it on the ground, in level flight or only as it powers up? 

[gsxrpilot]

I'm pretty confident I can shoot an approach using ForeFlight on the iPad. It's getting it's picture from the Stratus.  I've shot a practice approach under the hood with it and was pretty happy with it.

[jetdriven]

2 hours ago, cnoe said:

Just making sure we're on the same page here... The AHRS is in the Stratus2, not the iPad itself. The iPad display shows the same attitude no matter how it's positioned or tilted. You may have to look down (not the best idea in IMC) but the info you see is fairly accurate. Still, a certified solution is much much better.

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I get the AHRS is in the GDL-38 but wouldn't  looking at a roll instrument that is mounted to the yoke be a little disorienting?  Erik's solution is interesting.  

[MooneyBob]

I have my iPhone velcroed to my panel right above the altimeter. It fits there perfectly and it is right in line of sight. It doesn't cover my engine gauges since I have engine monitor with all the primary functions on it. Also my iPad mini is in the corner between the windshield and side window. 

[cnoe]

Jetdriven said: I get the AHRS is in the GDL-38 but wouldn't  looking at a roll instrument that is mounted to the yoke be a little disorienting?  Erik's solution is interesting.

 

*I have hell with editing on Tapatalk...

 

Yoke mounting certainly isn't in the normal scan. The tilt doesn't seem to be as much of a problem as the head bobbing up and down. I'm sure not recommending the iPad as one's first backup but it does have value IMO.

A Ram cradle mount on the center post with an iPhone (as shown at the top of this pic) might be a better mounting option for an emergency AI than the yoke. The side post mount looks good too.

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[LANCECASPER]

The Garmin 796 mounted to the top of compass post with a RAM U-bolt paired with the GDL-39 3D  works well as a backup. Hard to beat it for readability in direct sunlight. Synthetic vision, XM radio, ADS-B-in weather and traffic, etc, etc, With its battery and the battery for the GDL-39 3D you also have backup in case of an electrical failure. It's hard to justify spending a lot more for a panel mounted backup that doesn't do half as much.

[rbridges]

we really have it much better than pilots from years ago.  Just reading through these posts, most of us have up to 3+ options for an artificial horizon.  Albeit, some are not ideal, it's much better than having a single AI and it going belly up at a bad time.

[Marauder]

The Garmin 796 mounted to the top of compass post with a RAM U-bolt paired with the GDL-39 3D  works well as a backup. Hard to beat it for readability in direct sunlight. Synthetic vision, XM radio, ADS-B-in weather and traffic, etc, etc, With its battery and the battery for the GDL-39 3D you also have backup in case of an electrical failure. It's hard to justify spending a lot more for a panel mounted backup that doesn't do half as much.

Has anyone gone under the hood and tried flying approaches with these portables? I don't have have an AHRS capable GDL-39, but was curious if they did indeed perform as well as the more costly alternatives.

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[carusoam]

What I got from this thread....

1) Somebody added a vac gauge to my instrument panel.  Nice for knowing the pump is working currently.

2) The plane came with a second motorized vac pump system. Nice for knowing there is a plan B for running Plan A to failure.

3) Pump vanes wear slowly, but at a rate I might not notice or remember.

4) Carbon vanes fail in a catastrophic fashion. This makes having the gauge as good as having the vac light in the panel.

5) The Sandia device is looking pretty good.  A second airspeed indicator could be helpful. An AHRS(?) device is a nice addition.  I would want the sensor mounted where it doesn't bounce and slide off a shelf.

6) The modern JPI devices have vacuum indication and settable alarms.

7) continuing to fly on without an AI is not....recommended.

8) continuing on leads to increased potential of being in IMC.  The Turn coordinator is a good back-up.

9) continuing on in IMC  leads to increased potential of being in turbulance.

10) flying in IMC in turbulent conditions makes you realize the limitations of your instruments.  The TC is limited in this case. Flying with a sensitive/bouncing needle in IMC is to be avoided.

Good is the enemy of great. Don't settle for a good back-up device and use it to fly for an extended period of time over an extended distance.

Just my ideas on how sensitive and unusable a particular TC was during my IR training in NJ in winter.

Best regards,

-a-

 

[jetdriven]

I had a primary AI failure in actual IMC right after takeoff in a 402C a few years ago.  The light turbulence rendered the turn and bank indicator useless. Luckily I had a copilot set of gauges and flew home on those.  The company later took those out and the pilot lost the AI shortly after takeoff and crashed into a street nearly vertical. N402ME look it up.  Since then, I don't trust anything but a real attitude indicator.  

[aviatoreb]

20 hours ago, MooneyBob said:

Do you reset it on the ground, in level flight or only as it powers up? 

It does show the pitch of your ground stance when it fires up. SO I do reset it once in level flight.  That is not ideal, but keep in mind I think this is a fine 3rd attitude where the other two are certified.

[cnoe]

Please provide clarification on the CV1J4 filter usage.

The documented application for this filter is for installation on the exhaust side of a pneumatic air pump to filter/monitor carbon dust from pump vanes. Most older Js employ a suction or vacuum instrument system instead of a positive pressure system.

So I have to assume that individuals are installing this filter on the suction side of their pumps to prevent backflow contamination of the vacuum system in the event of a vacuum pump failure. As I understand it when the pump fails the existing vacuum in gyros etc. can cause the carbon dust to flow in a reverse direction. You would have 2 filters, one intake and one inline, right?

Having a backup electric vacuum pump I have a check-valve between the pump and the regulator so I see no need for this filter.

I'm just making sure I understand the motive for the inline filter.

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[aviatoreb]

1 hour ago, jetdriven said:

I had a primary AI failure in actual IMC right after takeoff in a 402C a few years ago.  The light turbulence rendered the turn and bank indicator useless. Luckily I had a copilot set of gauges and flew home on those.  The company later took those out and the pilot lost the AI shortly after takeoff and crashed into a street nearly vertical. N402ME look it up.  Since then, I don't trust anything but a real attitude indicator.  

That is quite a telling story.  I practice the turn coordinator partial panel thing - but I always figured that was for the much heartier than me - people who are better immersed than me - so I want a real attitude indicator for my airplane.  You however are a real daily flying ATP-type pro, so to hear you say the same thing is really telling to me.

[MooneyBob]

1 hour ago, aviatoreb said:

It does show the pitch of your ground stance when it fires up. SO I do reset it once in level flight.  That is not ideal, but keep in mind I think this is a fine 3rd attitude where the other two are certified.

That's my setup before I will get the Sandia SAI 340. It should be certified by now. 

[cnoe]

I had a primary AI failure in actual IMC right after takeoff in a 402C a few years ago.  The light turbulence rendered the turn and bank indicator useless. Luckily I had a copilot set of gauges and flew home on those.  The company later took those out and the pilot lost the AI shortly after takeoff and crashed into a street nearly vertical. N402ME look it up.  Since then, I don't trust anything but a real attitude indicator.  

A sobering NTSB report.

Often the transition to a turn coordinator (with AI failure) is described as a simple thing, but it sounds a lot more serious than that in true IMC. Like you I'd prefer a real backup AI for IFR flight.

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[Danb]

Chris I practiced approaches just with the svt and no other equip. We did about four down to minimums at Roanoke with each one ending right over the numbers. It was as if I was flying vfr the display with svt was that good.

[cliffy]

I have found that the transition from a failed AI to a good one to be problematic for many pilots. In training crews in Boeing simulators a failed AI (TACA B737 accident) caused many crews to fly the failed AI until control was almost lost (again TACA accident). When one was taught "best 2 out of 3" (we have 3 AIs in jets) then the problem went away. If you have only 2 AIs the problem is which one is correct and transitioning to the good one in full IMC may be more difficult than first envisioned. 

[jetdriven]

Pick one, roll wings level, watch the DG. If it's turning use the other one.   If the vacuum source is lost, the DG won't be reliable, use the whiskey compass.  Yes, transitioning and identifying the failed AI is difficult. Turbine airplanes have no TC but they have 3 independent AIs.  The Dynon D100 in a panel dock or a hard mounted iPhone with an AI display would make a good 3rd option. 

Our primary AI is an electric castleberry unit.  The standby is vacuum.  For unusual attitude practice I'll put the other pilot under the hood, close eyes, put the plane into a 45 degree bank, then cage the electric AI. Now the differ by 45 degrees.  Open your eyes and recover.  Very disorienting but the recovery procedure appears to work. 

[FlyDave]

On 11/26/2015, 11:49:44, FlyDave said:

Erik,

I can't find anything in the electronic copy of the POH that I have. I'll look through the POH and documents with it when I'm at the airport tomorrow.

But take a look at the bottom of this pic for the placard:

 

Erik,

I didn't have any documentation in the POH in the plane or in the log book materials on this electric standby vacuum pump. I went to mooney.com and downloaded the AFM supplement for this system and can't find any reference to the placard in my plane.

In the attached supplement I found the following verbiage:

The standby vacuum system consist of an electric motor driven dry air vacuum pump mounted in the radio racks behind the aft cabin bulkhead. System plumbing for this pump is routed along the left hand side of the aircraft to a manifold /check valve/regulator assembly mounted on the cabin side of the firewall. The manifold/check valve/regulator assembly provides both isolation and interconnect functions between the main engine driven and the standby electrically driven vacuum pumps. A circuit
 breaker/rocker switch labeled STBY VAC is provided for activation of the standby pump. When activated, operation of the standby
 vacuum  pump is verified by the illumination of annunciator light labeled STBY VAC ON. Standby  pump  output is monitored by a panel mounted vacuum gauge

It sounds like the 2 pumps are isolated when the switch is on but I'm not sure what that would do to the engine driven pump if was still working. I'm going to call Mooney on Monday to find out if the placard in my plane is valid. Please let me know if this is the same pump you have and if you have found any documentation on concurrent operation.

Electric Standby Vacuum Pump - RevG.pdf

[cliffy]

jetdriven- not a bad technique but it has to be practiced until it is second nature and redone every year.

Im sure you'd agree that if the student only wants one demonstration that won't cut it in a real emergency for him.

[carusoam]

Adding to the discussion of smart phone as a back-up device...

1) The battery doesn't last long when working really hard.  The internal GPS may drain the battery in less than an hour.

2) Know the limitation of yours or have it plugged in.  It gets pretty hot too.

Best regards,

-a-

[Andy95W]

Best alternate vacuum for me is an STEC autopilot.  It uses the turn coordinator to keep the wings level, and in wing leveler mode you can fly the course your GPS tells you.

If you have GPSS it will still fly a rock-solid GPS approach to minimums- all while your AI and DG are dead.

[cliffy]

1395- Now that is a good option. +1 for the STEC   (-2  for the price:-)

[flyboy0681]

I just got back from 1.5 hours under the hood and kept the AI covered the entire time.

[Mooneymite]

38 minutes ago, flyboy0681 said:

I just got back from 1.5 hours under the hood and kept the AI covered the entire time.

Every time I go out for proficiency under the hood, I fly most of it partial panel using the turn coordinator.  When you lose your vacuum pump, the trick seems to be to get on the back-up instruments as soon as the lo-vac light comes on...while the gyros are still spinning.  Transitioning from a "leaning gyro" to the turn coordinator is tougher than making the transition immediately.

Partial panel with a Garmin 430 is sure a lot easier than the bad old days of VOR/ADF....almost like cheating!