Accident Analysis - Single Point Failure

[pelmet]

Worth watching and thinking about what you might do in such a situation...

https://www.youtube.com/watch?v=7sfHlzv ... e=youtu.be

[iflyforpie]

When I rebuilt a Lake Buccaneer years ago it had an emergency vacuum system that just ran off the engine manifold. A simple valve like alternate static and some extra plumbing going to a hole drilled in an intake riser.

I’d imagine you’d have to throttle back to get the required vacuum, but good for a cloud break or a precision or SCDA approach.

[pelmet]

It is in known what clouds were encountered enroute. But this loss of vacuum happened 2.5 hours into the flight and they said he had 5 hours of fuel. If favourable, one could turn back toward the departure airport which had good weather and set the aircraft up for extended range flight depending on the upper winds. There likely were other options available.

[pelmet]

One might also notice that the video said that the Bonanza lost control a mere 4 minutes after entering the cloud after spending a significant amount of time above the cloud with the faulty vacuum system.

So, if you are in this situation, perhaps you can simulate instrument conditions above the clouds to see how well you can handle them. There were two pax with him so they might be able to help. One could put the map up or other devices , possibly including a ball cap and see if you can maintain wings level or do some maneuvers above the clouds for 15 or 20 minutes. If not, time to be sure that you stay in the clear.

Something to consider if in a situation like this.

[aeroncasuperchief]

With alternate vacuum systems available, electric A/H, adhering to manufacturers pump replacement times, A back-up GPS 6 pack and partial panel re-training or self training , This accident should be a thing of the past ! Who flies around with 1 magneto these days?

[pelmet]

All very true. But....

If caught in this situation as experienced by the accident pilot, would you have any suggestions on what could be done better.

[photofly]

All very true. But....

If caught in this situation as experienced by the accident pilot, would you have any suggestions on what could be done better.

It feels disrespectful, somehow, given that he died. I'm not sure why, this time more than others. But it does.

[lownslow]

Who flies around with 1 magneto these days?

I do!

[lownslow]

Worth watching and thinking about what you might do in such a situation...

https://www.youtube.com/watch?v=7sfHlzv ... e=youtu.be

While I have a tiny bit of Bonanza time it's been a while. Are they not stable enough to trim for a couple hundred feet per minute descent and just sit on your hands?

[iflyforpie]

Beechcraft recommended putting the gear and approach flap down, reducing power, and trimming up to create a more stable platform when in inadvertent IMC.

[aeroncasuperchief]

I do!

What A/C type ?

[pelmet]

All very true. But....

If caught in this situation as experienced by the accident pilot, would you have any suggestions on what could be done better.

It feels disrespectful, somehow, given that he died. I'm not sure why, this time more than others. But it does.

Thanks,

Might feel that way but if only you could see the lives you might have saved from someone who read your post. You never get to see that. It is more important than a guilty feeling though.

Thanks for the other posts as well.

[photofly]

Alright, well. There isn't much to say that isn't somewhere in the voice-over already. What would I do differently? I'd immediately abandon my thoughts about getting to my destination and focus on getting the airplane on the ground in once piece.

"N440H declaring an emergency, vacuum failure therefore no attitude reference, in VMC on top, request no-gyro vectors to any airport within 200nm showing clear skies."

If nothing with suitable weather in range, Check if any of the coastal airports had a ceiling above 500'. If so, then head out over the ocean, and do a sit-on-your-hands descent to break out. If you can't get inland then put the damn thing down on the beach. The nice thing about flying over open water is there's very little to collide with.

The one time I had a vacuum failure on an IFR flight, the air traffic controllers took it very seriously indeed.

I just listened to the beginning of the video again - three people on board. What a waste.

[PilotDAR]

Who flies around with 1 magneto these days?

Anyone who flies a Lycoming IO-540 with a D6LN-3000 "dual" magneto. I disassembled one at the engine shop I used to work at, to find that the single gear which drives both magnetos had two consecutive teeth missing. Anyway....

One of the occasions where I lost my artificial horizon, was of course, moments after I'd entered a cloud -it just slowly rolled over. I began to follow it, but needle, ball and airspeed told me not to believe it. It was a bit of a mind bender though, as my suction gauge showed lots of suction, the DG seemed to be working (so I could return to the desired heading), and the "GYRO" flag in the artificial horizon had not dropped, indicating that it still had adequate vacuum to operate. But, as I exited the cloud, more or less straight and level, the AH was dead on its back. This was later determined to be the result of a bearing failure in the gyroscope itself, rather than a vacuum failure - so the single point failures take more than one form. But, in the airplane sense, the airplane really had not had a single point failure. The certification standards required dual power sources for specified instruments, which is to prevent a more widespread failure. That's why you'll notice most GA T&B's say "DC Electric", so you know that they are not dependent upon vacuum. If you decide to fly, you must master the skills to manage failures which could be reasonably anticipated. If you want to fly instruments, this includes partial panel. Or, you choose to avoid flying in instrument conditions, or you assure system redundancy.

I installed the engine manifold vacuum on a friend's 182RG (the one with the D6LN-3000 mag). It worked okay, though required engine management, and did not work well at altitude. Ultimately, he chose the electric vacuum pump instead, though it's heavy! And, if you have an electrical failure while using it.... well you just got a lot busier anyway!

[aeroncasuperchief]

N440H declaring an emergency, vacuum failure therefore no attitude reference, in VMC on top, request no-gyro vectors to any airport within 200nm showing clear skies."

If only every GA pilot could recite the above to memory AND stick with it if the time comes !

How many pilots have flown in real IMC and had the vac pump "failed" while the co-jo pilot/instructor has an electric back-up? Problably never and therefore the training you got many years ago and didnt do again isnt even realistic !!!

In the past, under controlled and safe conditions, I have done IMC with and without an IFR rating and tried to fail myself ( Vertigo is terrible !! ) BTW, what controller is going to give you a "block" airspace in IMC to train? I used to do partial panel under the hood recoveries at night over Madoc Ont. with an instructor,,,, still not realistic enough!

Self re-training/ currency is the key to survival

[aeroncasuperchief]

Anyone who flies a Lycoming IO-540 with a D6LN-3000 "dual" magneto. I disassembled one at the engine shop I used to work at, to find that the single gear which drives both magnetos had two consecutive teeth missing. Anyway....

Some desk bound design engineer and a bean counter must have been in bed together to "invent" that farce of a dinosaur!

They were not as friendly to work on as a single mag and therefore led to its unreliability

One of the occasions where I lost my artificial horizon, was of course, moments after I'd entered a cloud -it just slowly rolled over. I began to follow it, but needle, ball and airspeed told me not to believe it. It was a bit of a mind bender though, as my suction gauge showed lots of suction, the DG seemed to be working (so I could return to the desired heading), and the "GYRO" flag in the artificial horizon had not dropped, indicating that it still had adequate vacuum to operate. But, as I exited the cloud, more or less straight and level, the AH was dead on its back.

Why couldn't they mandate an alternate AH ( Electric ) and force the industry to sell them at the same cost as a turn coordinator ! Problem solved !


Thinking of Magnetos, WHO invented the plastic/rubber pucks that fall out and into the accessory case when the mags are removed ? Epic FAIL !!

[PilotDAR]

Why couldn't they mandate an alternate AH ( Electric ) and force the industry to sell them at the same cost as a turn coordinator ! Problem solved !

'Cause the electric ones are way more mechanically complex to self erect. And, as we know, the aviation industry can't really be "forced" to do anything for a particular price (other than high). The present system designs work fine, within their intended operational limitations, and in the hands of a competent pilot.

[rigpiggy]

In the states i can remove a t&b, and replace with a 2nd AI, not so in canada. I fly several turboprops that the only vacuum instrument is my t&b, do you think i would be better off with a 3rd AI? In addition i have an ipad with a ads-b/ bluetooth AI backup. Sh!t breaks all the time, have a backup

[PilotDAR]

turboprops that the only vacuum instrument is my t&b

There's your hint, the design of the instrument power supplies meets the following requirement (my bold):

Sec. 23.1331

Instruments using a power supply.

(a) For each airplane--
(1) Each gyroscopic instrument must derive its energy from power sources adequate to maintain its required accuracy at any speed above the best rate-of-climb speed;
(2) Each gyroscopic instrument must be installed so as to prevent malfunction due to rain, oil, and other detrimental elements; and
(3) There must be a means to indicated the adequacy of the power being supplied to the instruments.
(b) For each multiengine airplane--
(1) There must be at least two independent sources of power (not driven by the same engine), a manual or an automatic means to select each power source, and a means to indicate the adequacy of the power being supplied by each source; and
(2) The installation and power supply systems must be designed so that--
(i) The failure of one instrument will not interfere with the proper supply of energy to the remaining instruments; and
(ii) The failure of the energy supply from one source will not interfere with the proper supply of energy from any other source.

[iflyforpie]

The turboprop I fly the only vacuum instrument is the vacuum gauge (which is only for pulling down the boots and controlling pressurization). For gyro instruments it has two electrically powered Attitude Heading Reference Systems (AHRS) and one independent battery powered Electronic Standby Instrument System. It would take multiple failures to knock all of those out.