Page 1 of 2

Accident Report re: electronic gyro install error?

Posted: Tue Dec 27, 2022 8:32 pm
by GAHorn
AvWeb reported this accident recently. I am posting it because of the recent popularity of Electronic “gyro” Instrument conversions.
No blame is being insinuated on the new instruments…but discoveries may point to improper conversion/installation/removal of old equipment.
(I believe the reference to a “vacuum pump cover” may actually intend to be a “blanking-cover” to close-out the vacant mounting-pad.)

September 14, 2022, Conway, S.C.

Piper PA-28R-201 Arrow III

The airplane was destroyed at about 1222 Eastern time as the pilot attempted an off-airport landing after reporting total engine failure. The pilot and passenger were fatally injured. Visual conditions prevailed.

Shortly after departure, the pilot reported to ATC that he was having problems with cockpit instrumentation resulting in difficulty maintaining assigned headings. He wanted to return to the departure airport and was not declaring an emergency. About 30 seconds later, the pilot reported loss of engine power, that he was unable to make it back to the departure airport and that he had identified an off-field landing area. Witnesses reported seeing the airplane but they heard no engine sound. The airplane impacted a tree and a powerline before coming to rest. A post-crash fire consumed much of the wreckage.

Examination revealed catastrophic failures of three of its four connecting rods. The left engine crankcase half was fractured inboard of the #4 cylinder mounting pad. During engine disassembly, a vacuum pump cover was found installed to the vacuum pump drive pad without a gasket. Maintenance records revealed the airplane had just undergone an avionics upgrade, which included removal of the vacuum system and installation of electronic flight instruments. The accident flight was the first one after the upgrades
.

Re: Accident Report re: electronic gyro install error?

Posted: Tue Dec 27, 2022 8:50 pm
by wingnut
Most avionics techs that I've met are not mechanics and should <not> be removing systems without appropriate supervision. They may have an A&P cert, but most do not have the experience or aptitude, nor enough opportunity to stay actively engaged and current on mechanical systems. Sad deal.

About 25 years ago I was doing some work on a Bonanza at another shop on the field. An avionics crew was also working on it, installing later model wing tips and strobes. The avionics tech zip-tied the strobe wiring to the landing gear retract rods.

In fairness, I've never met a good mechanic that could do anything with avionics. Most struggle with basic electricity troubleshooting.


<corrected by moderator>

Re: Accident Report re: electronic gyro install error?

Posted: Wed Dec 28, 2022 6:14 am
by ghostflyer
OMG wing nut you bring a tear to my eye . that’s a bit harsh hitting at the poor avionics guys. But due to industry pressures and the lack of qualified people there are some avionics guys that do need mechanical training and also there are some mechanical guys need avionics training . it’s due to the changing of technology , the lines of mechanical and avionics are getting very blurred.
In my humble opinion it’s all about training and competency and being able to demonstrate it . This also includes pilots , who are allowed to do some maintenance on their aircraft. The amount of errors by pilots doing maintenance is unbelievable.

Re: Accident Report re: electronic gyro install error?

Posted: Wed Dec 28, 2022 7:40 pm
by voorheesh
Avionics technicians involved in aircraft maintenance including repairs, installation, and alterations should work under supervision of a certificated repair station with specific authorizations for work performed. A repair station should have expertise and procedures in place to ensure any task is accomplished properly. Many “radio shops” perform excellent work and follow up, but there are probably some renegades out there.

The AvWeb piece doesn’t conclude the engine failure was caused by the improperly installed plate and does not mention who installed it. It would be interesting to learn the full story.

Re: Accident Report re: electronic gyro install error?

Posted: Wed Dec 28, 2022 8:10 pm
by voorheesh
The AvWeb story makes me wonder: Could they have been buttoning that job up and couldn’t come up with the right gasket? Could some well meaning person (avionics or maintenance) have put the vacuum cover plate on the engine so it wouldn’t get lost? We’ll finish the job when gasket comes in. Then they might forget about it. Or another mechanic looks at it and assumes it's a done deal. Unfortunately, mistakes like that can happen and worth reminding ourselves.

Re: Accident Report re: electronic gyro install error?

Posted: Wed Dec 28, 2022 9:52 pm
by GAHorn
voorheesh wrote:Avionics technicians involved in aircraft maintenance including repairs, installation, and alterations should work under supervision of a certificated repair station with specific authorizations for work performed. A repair station should have expertise and procedures in place to ensure any task is accomplished properly. Many “radio shops” perform excellent work and follow up, but there are probably some renegades out there.

The AvWeb piece doesn’t conclude the engine failure was caused by the improperly installed plate and does not mention who installed it. It would be interesting to learn the full story.
There is no general requirement for an avionics installer (A&P) to work under the supervision of a CRS.

I once was loaned a Twin Bonanza (Excalibur Conversion 8-cyl Lycoming IO-720s) ) for the 1980 Christmas Holidays to take to Atlanta to visit in-laws. It was just fresh from Annual Inspection.

Without asking, the wife volunteered me to drop her friend off at her friend’s grandparents for their holidays…. in ENID, OKLAHOMA :!: (nowhere near our route from Bryan/College Station to ATL( :roll:

The entire U.S. from East Texas, Oklahoma, LA, MS, GA… ALL had a large snowstorm with ceilings of 200-400 and viz 1-2 miles the entire route. I was pizzed I had to make an extra leg in that weather which wasn’t even on our route. :evil:

We left CLL and a couple hours later landed just after-dark in a snowstorm and winds gusting to 35 kts. Wind-chill Temp was about Zero-F.

I gave the lineman refueling instructions and helped our “guest” get her luggage into the Enid terminal to meet her grandmother…paid the fuel bill…then dashed back out into the blizzard to jump up the air-stairs (D-Model) to get out of the Blizzard and get on our way to ATL.

My conscience was nagging me as I raced thru the darkend snow-storm toward the airplane and just as I reached the right wingtip I decided to make a dash-around the airframe to check fuel-caps were properly installed…. And racing around to the left side… SLIPPED AND FELL on a ramp COVERED IN OIL!

The annual inspection had included changeout of the left-engine tach-generator…which was held onto the engine with 4 plain nuts…that had been put on only FINGER-TIGHT and never properly torqued! The engine barely had enough oil to leave one drop on the bottom of the dipstick!

If my wife had not promised her friend a trip to Enid ….instead of us going direct to Charlie Brown/Fulton County at Atlanta….. That engine would have failed somewhere over Mississippi …and the rest of the flight and approach to FTY would have been in 200-1 in blowing snow weather. 8O

(We spent two hours with a flashlight and a wrench in the dark using frozen fingers on an open ramp properly tightening that tach-generator, then used the jet-fuel truck to wash-down the engine to check for leaks in that blowing blizzard. Got to FTY about 2 A.M. and completed a two-engined approach in snow.)

Sometimes we survive only due to pure luck or fate…events which have killed good friends.

Re: Accident Report re: electronic gyro install error?

Posted: Wed Dec 28, 2022 10:18 pm
by Richgj3
There was a long discussion about this accident on another forum months ago centering on skepticism that enough oil could come out of that spot in the period of time described to cause the failure. No question that the gasket was missing. But?

I had a Comanche 250 years ago where the mechanical fuel pump safety wire was not done properly and the bolts loosened. The result was a small amount of oil on the hangar floor after a four hour flight.

Re: Accident Report re: electronic gyro install error?

Posted: Thu Dec 29, 2022 3:27 am
by mmcmillan2
GAHorn, great story!

Re: Accident Report re: electronic gyro install error?

Posted: Fri Dec 30, 2022 3:45 am
by mit
Yes, but where the gas caps on???? :lol:

Re: Accident Report re: electronic gyro install error?

Posted: Sun Jan 01, 2023 5:31 am
by GAHorn
The right side of the airplane was facing toward the FBO office and the flood-lights of the ramp…Due to the bitter cold conditions I was sorely tempted to just climb aboard and close the door… but my conscience made me go to to the dark left-side to make a hasty-check of those gas-caps. In the dark, that oil-soaked left engine and ramp would have been unnoticed otherwise. Ernest K. Gann was correct about Fate and Fortune.

Re: Accident Report re: electronic gyro install error?

Posted: Tue May 02, 2023 8:52 pm
by Avee8or
I will be removing vacuum system shortly--I have an O300 with the Universal Tow All alternator/vac pump STC. Should my A&P fabricate a plate or would one such as the Superior SL60430 Cover (aircraft spruce) be suitable? Yes--they sell the gasket too!

Re: Accident Report re: electronic gyro install error?

Posted: Tue May 02, 2023 10:31 pm
by mit
Avee8or wrote:I will be removing vacuum system shortly--I have an O300 with the Universal Tow All alternator/vac pump STC. Should my A&P fabricate a plate or would one such as the Superior SL60430 Cover (aircraft spruce) be suitable? Yes--they sell the gasket too!
What is a universal Tow All???

Re: Accident Report re: electronic gyro install error?

Posted: Wed May 03, 2023 1:03 am
by Bruce Fenstermacher
Avee8or wrote:I will be removing vacuum system shortly--I have an O300 with the Universal Tow All alternator/vac pump STC. Should my A&P fabricate a plate or would one such as the Superior SL60430 Cover (aircraft spruce) be suitable? Yes--they sell the gasket too!
I just did a little diggind on this Universal Tow All alternator/vac pump thing. I could be wrong but as I understand it it is a alternator with a vacuum pad on the end of it. If this is the case I can't see how any engine oil would get to the vacuum pump pad. You probably could get away with no cover if this is the case though a cover would neaten it up and cover the turning spline.

Getting off subject a bit a fellow I'm helping install an overhauled engine in his turbo Mooney sent me to the TCDS for his Mooney looking for any reason the factory single cylinder EGT had to remain installed as he had a 6 cyl JPI CHT/EGT system. Couldn't find anything that said the EGT needed to stay but did notice a vacuum pump is required equipment on his model Mooney. He'd mentioned he wanted to get rid of his vacuum pump at some point so I told him that might not be as easy as he thinks.

Re: Accident Report re: electronic gyro install error?

Posted: Wed May 03, 2023 7:38 pm
by voorheesh
Does the TCDS for this Mooney require a vacuum pump or a vacuum system of which the pump is a part? Could a subsequent STC (Instrumentation not powered by vacuum) modify the requirement? Is it possible that Mooney intended these models to have a vacuum system per type design? My recollection from conversations with ACO was that manufacturers (applicants for TCDS/Airworthiness Certificates) in their application to FAA specify the design parameters to meet applicable certification regulations and the FAA reviews and issues. Subsequent modifications are similarly submitted for approval. Do you have a similar understanding?

I ran into a vacuum pump issue involving a fatal accident of a twin Cessna years ago. It was flying under IFR (nighttime, no moon, over desert) with a properly placarded/inop vacuum pump. Our issue was the Cessna Kind of Equipment List was silent on requirements for vacuum pumps. The Master MMEL (our operator was not using) specified “day VFR” only for operations with one inop pump. We went around with ACO on this in search of a safety recommendation. This was not resolved IMO and it seems there is a lack of FAA consistency when it comes to these systems. My recommendation to pilots and owners is to be highly careful when dealing with systems you may have to rely on for basic aircraft control. Legality is important but basic reliability can be life saving.

Incidentally, during our inquiry on the Cessna accident, the last thing on our mind was assignment of blame.

Re: Accident Report re: electronic gyro install error?

Posted: Wed May 03, 2023 9:53 pm
by GAHorn
What year Mooney?, Bruce? Does it have a PC control? (rudimentary wing-leveler as part of it’s TC…usually has a small button on the yoke to momentarily disengage…part of the basic airframe. operates on vacuum.) Knowledgeable Mooney pilots who wish to long-period disable it… pull the button UP slightly out of the yoke, which creates a vacuum leak in the system and disables ti.)