Vacuum pump economics

[RobertGary1]

I wonder if there is anything with more of an aviation upgrade in price than a vacuum pump. Even a little 211cc is $400 new. If it were a car part it would be under $20. I have 3 AHRS but have had enough glass cockpit failures over the years that a backup vacuum attitude is confronting but damn $400.  
 

so why? Lack of competition? Liability?

Edited May 16, 2021 by RobertGary1

[Will.iam]

1 hour ago, RobertGary1 said:

I wonder if there is anything with more of an aviation upgrade in price than a vacuum pump. Even a little 211cc is $400 new. If it were a car part it would be under $20. I have 3 AHRS but have had enough glass cockpit failures over the years that a backup vacuum attitude is confronting but damn $400.  
 

so why? Lack of competition? Liability?

I would guess the certification process cost money and cars don’t need a certified one. In fact neither does an experimental. You got to pay to be offical. 

[RobertGary1]

34 minutes ago, Will.iam said:

I would guess the certification process cost money and cars don’t need a certified one. In fact neither does an experimental. You got to pay to be offical. 

Yet can't think of anything else that has a 20X price difference. Tires, no. Spark plugs, no. Fuel, no. Alternators, no. So its more than that.

[Raymond J1]

Loss of horizontal reference is a fear that is priceless.

[RLCarter]

My guess is liability, most mechanical items in aviation haven’t changed much other than price. There was a guy that use to rebuild his own vacuum pumps for his Comanche, he would rebuilt it about every 300 hrs or so (before it failed) and would take less than an hour total. Spruce sells the kits for just north of $100.00. For reference, my vacuum pump on my 7.3L was $100.00 and lasted about 80k miles or 6 yrs

[warren.huisman]

Don't under estimate the economics of car parts Vs aircraft parts.  Volume alone is a huge factor.  Manufacturing process for millions of parts are quite different to hundreds of parts.  Prototype vehicles (which the auto companies will build a few hundred) will cost millions each largely due to how the components are manufactured and how the vehicles are assembled (by hand).  Aircraft manufacturing isn't all that different from prototype vehicle manufacturing.  It's not practical to compare automobiles to aircraft - the scale effect is huge.  

[Hector]

I wonder if there is anything with more of an aviation upgrade in price than a vacuum pump. Even a little 211cc is $400 new. If it were a car part it would be under $20. I have 3 AHRS but have had enough glass cockpit failures over the years that a backup vacuum attitude is confronting but damn $400.  
 
so why? Lack of competition? Liability?

My bother in-law has gone all glass and he is getting his airplane back from the avionics shop tomorrow (5/17). The vacuum system was removed and he had both a regular and backup vacuum pump. If you are interested I’m sure he selling that stuff cheap.


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[Guest]

Vacuum pumps cost about $0.50 per hour, oil filters cost about $0.50 per hour.  Last year my insurance was about $80.00 per hour and hangarage was even more.

Maintaining and operation it seems cheap by comparison.

Clarence

[A64Pilot]

If it’s still available you can go to an Airwolf / Pesco wet pump and be done with it.

‘So far as rebuilding them, it’s really doesn’t work well, the vacuum pump body if you look at it, is coated with teflon or some other similar costing, once or if that costing wears off, then the wear on the pump itself is fast. I believe you can usually rebuild them once , but I don’t.

[201er]

6 hours ago, RobertGary1 said:

Yet can't think of anything else that has a 20X price difference. Tires, no. Spark plugs, no. Fuel, no. Alternators, no. So its more than that.

Fuel pressure transducer, no back clutch spring, electric fuel pump....

[Browncbr1]

$400 is a fart in the wind for aviation; perhaps not even worthy of of cost accounting.    Extend the life of it by replacing the gasket and the urethane coupler every few years.  

[Raymond J1]

I repair vacuum pumps for all aircraft in the aeroclub, it takes an average of 800 hours before signs of weakness on rapco "dry". After repair, the time the new pallets have been lapped, there is not 100% performance in the first 50 hours. There is a tool to be made or procured to do the repair. With regular monitoring, the vacuum power is economical, reliable, light. In most cases, the element of weakness is the sealing gasket (in the foreground in the next photo)

[PT20J]

As I understand it, there a two primary failure modes:

1. The graphite vanes are ablative and wear to self-lubricate and create a good seal.  As they wear, they shorten until they eventually break and jam the pump which causes the frangible shaft coupling to shear so as to protect the accessory case gears. Tempest pumps have a feature to permit direct observation of the amount of wear. Replacement or rebuilding at 500 hrs should greatly reduce the risk.

2. The Garlock shaft seal (not the seal between the pump and case) can leak oil into the pump which mixes with the graphite dust and gums things up eventually jamming the pump. This one is harder to predict, but replacement at 500 hrs and/or some reasonable calendar age should reduce the risk.

Skip

[RobertGary1]

6 hours ago, M20Doc said:

Vacuum pumps cost about $0.50 per hour, oil filters cost about $0.50 per hour.  Last year my insurance was about $80.00 per hour and hangarage was even more.

Maintaining and operation it seems cheap by comparison.

Clarence

Ive had vacuum pumps and attitude indicators fail in the clouds. When this was my primary I wouldn’t hesitate to spend $400 on it. Now that it’s my third backup it bothers me more.   but I’ve had enough failure in the g1000 Garmin system that I really like that simple backup. 

[carusoam]

Why...

Because they can...

But not for long...

Two independent AIs are good...

Three is a bit excessive...

Out goes the vac system.....

PP thoughts only, not an instrument guru...

Best regards,

-a-

[RobertGary1]

33 minutes ago, carusoam said:

Why...

Because they can...

But not for long...

Two independent AIs are good...

Three is a bit excessive...

Out goes the vac system.....

PP thoughts only, not an instrument guru...

Best regards,

-a-

A man with two watches never knows what time it is. 

[AIREMATT]

6 minutes ago, RobertGary1 said:

A man with two watches never knows what time it is. 

Hopefully he knows enough to look at the wall clock (or T/C or AHRS) to break the tie.

[RobertGary1]

23 minutes ago, AIREMATT said:

Hopefully he knows enough to look at the wall clock (or T/C or AHRS) to break the tie.

T/c are old school. Most are taking them out. Rate of turn and quality of turn is shown on the pfd. 
But that is my point. With two AHRS there is no tie breaker. 

Edited May 16, 2021 by RobertGary1

[RobertGary1]

Just now, nosky2high said:

FWIW, I’m going with an electric attitude indicator (with inclinometer) in place of my turn coordinator as backup. I like three options. My tempest tornado vacuum AI/DG, the electric AI, and finally my iPad if I’m really having a bad day. For those with an autopilot like an stec or trutrak(wishful thinking I know) that’s another layer of security. Just a Sunday rambling brainstorm from a 2100 hour vintage moony IFR flyer since first moony purchase back in May 2011. Bottom line; single engine, single pilot IFR takes a high level of dedication to mitigate most but never all the risks. 
 

AH

Recommend the gi-275 for that electronic attitude. Includes inclinometer and rate of turn indicator . 

[RJBrown]

15 hours ago, RLCarter said:

My guess is liability, most mechanical items in aviation haven’t changed much other than price. There was a guy that use to rebuild his own vacuum pumps for his Comanche, he would rebuilt it about every 300 hrs or so (before it failed) and would take less than an hour total. Spruce sells the kits for just north of $100.00. For reference, my vacuum pump on my 7.3L was $100.00 and lasted about 80k miles or 6 yrs

Average mph in an automobile is about 30. I didn’t believe it until I had a Garmin “street pilot”, an early automotive GPS (pre 2000) that was housed in the same shell the early Garmin portable had. One of its long term functions was average speed. My average speed in over 100,000 miles of drinking was about 30. 
That said the vacuum pump in your Ford lasted over 2600 hours. 
Am I crazy to say that certification rules guarantee old tech crappy parts. DOT has gotten way better results than the FAA. 

[Stetson20]

11 hours ago, RJBrown said:

Average mph in an automobile is about 30. I didn’t believe it until I had a Garmin “street pilot”, an early automotive GPS (pre 2000) that was housed in the same shell the early Garmin portable had. One of its long term functions was average speed. My average speed in over 100,000 miles of drinking was about 30. 
That said the vacuum pump in your Ford lasted over 2600 hours. 
Am I crazy to say that certification rules guarantee old tech crappy parts. DOT has gotten way better results than the FAA. 

“100,000 miles of drinking…”

Freudian slip? 

[PT20J]

21 hours ago, RobertGary1 said:

But that is my point. With two AHRS there is no tie breaker. 

I’ll have  G3X, G5 and GTX 345 bluetoothed to iPad. 

I’ve had a KI 256 and a KG 102 fail. Never had a vacuum pump fail when replaced at 500 hr intervals. So, if one has mechanical gyros, perhaps they should overhauled on a schedule. Good (expensive) insurance.

[Guest]

2 hours ago, Stetson20 said:

“100,000 miles of drinking…”

Freudian slip? 

With that much drinking, the speed of 30 makes sense.

Clarence

[thinwing]

Lawsuits....vacumn pump fails while IMC,pilot not current partial panel,grave yard spiral with all onboard deceased,multi million dollar verdict against vacumn pump mfd and anybody else associated with it.Mfd liabilty insurance explodes to cover potential liabilty as multiple torts have proven vacumn pumps driving the sole attitude instrument unsafe.

[RobertGary1]

45 minutes ago, PT20J said:

I’ll have  G3X, G5 and GTX 345 bluetoothed to iPad. 

I’ve had a KI 256 and a KG 102 fail. Never had a vacuum pump fail when replaced at 500 hr intervals. So, if one has mechanical gyros, perhaps they should overhauled on a schedule. Good (expensive) insurance.

That's basically where I am. So even though I have no shortage or AHRS (I think your 345 will also provide AHRS to your G3X if it detects a failure) having a mechanical backup doesn't seem like a bad idea.

In the G1000 I have had the AHRS reboot in flight with a message "hold wings level". What if some bug in the AHRS handshaking the Garmin products do (they constantly compare each other) that causes them all to reboot you'd be dead without another backup.

 

-Robert