gmcjetpilot
Well Known Member
In another thread "statistics" where brought up. It was implied Lycomings are falling apart and alternative engines are bullet proof, at least the bottom end. So I decided to look my self. The goal was to filter out as much as I could to find the number for LOSS OF POWER, for each engine type, Lyc, Subaru, Mazda, Chevy, Ford. The Mazda, Ford and Chevy are fairly easy to search since there are so few accidents. Subaru had the highest total accidents of the Alternative Engines, due to fleet size I assume.
Using the NTSB data I tried to find the answer. Of course fleet size and hours of utilization is hard to pin down. This is how I attacked it.
For the alternative engines I searched for the engine name and variations. Than I went through each probable cause to determine if the engine was the cause and what part.
I eliminated any Undetermined, WX, Pilot Error or Airframe issues, so if the math does not add up that is why.
For the Lycoming I could not just type that in. So I searched the reason or probable cause field with key words such as: Crankshaft, Connecting Rod, Rod Cap, Bearing - failure, fatigue and fracture. Than I went through the results and eliminated other engines and as with the alternative engines, undetermined, WX, pilot error and airframe. The data base seems to go back to 1985, although I searched back to 1970. So assume this is 22 years worth. If it was not in the database I did not included it. No claim of perfection her just a good broad swipe.
Accidents due to internal Engine Failure
Lycoming (all)
32 total accidents
17 crankshaft failure, fatigue & Fracture, 1 experimental
15 rod, rod cap, rod bolt, failure, fatigue & Fracture, 2 experimental
[Note: maintence or improper engine assembly, e.g., under torquing rod bolts was included. There where at least 6 due to improper maintenance or manufacture defect. 3 failures in Experimental's.]
Breaking the "32" down to just typical "RV" engines failure/fatigue/fracture:
360s 4 crank & 4 rod failure, fractures and fatigue - 8 total
320's 1 crank & 1 rod failure, fractures and fatigue - 2 total
235's 0 crank & 1 rod failure, fracture and fatigue - 1 total
Subaru
42 accidents
16 pilot error
8 Undetermined
18 total ancillary & mechanical failures:
Chevrolet / General Motors
13 total accidents and (1) major engine failure, (2) fuel related and (1) reduction drive.
The following Chevy or GM engines used: 5-V8, 6-V6, 1-4 cyl, 1-corvair
Mazda
Total 7 accidents: (1) Cooling, (1) Lube System, (1) exhaust/prop, (3) Carb/Fuel sys
Volkswagen
36 total accidents: (2) cranks, (1) lube system, (3) Ignition, (3) Carb/fuel
Ford
Total 8 accidents: (1) Cool, (1) Lube external, (1) Ignition, (1) Fuel (carb ice)
(2) Model-A's, (6) V6
*********************************************************
Totals - accidents due to core engine failure
Lyc 32 (11 for 235, 320 and 360's only)
Subaru 6
Chevy 1
Mazda 1
VW 3
Ford 0
The above ignored electrical, cooling, ignition, turbo, timing and fuel issues. Of the alternative engines, adding the electrical, cooling, fuel and misc, you would have this.
Total accident due to loss of power core + ancillary
Subaru 18
Chevy 4
Mazda 6
Ford 4
VW 9
The higher number for the Subaru & VW is no doubt related to a larger fleet size. It is clear that the ancillary items on alternative engines, electrical, cooling, fuel and misc cause more loss of engine power than rods and cranks. The VW had almost as many accidents as the Subaru, but most where undetermined, pilot or other.
This is not a PERFECT cut at it, only a broad brush approach. I could have missed other "core" causes of loss of power, but a good faith effort was made.
Of all the Lyc powered Experimental planes, there where only (3) hard engine failures.
I did not search for fuel issues, starvation, carb ice, vapor lock and so on with the Lyc but there are 100's of fuel related accidents, but I did not include fuel starvation or carb ice with any of the above.
The fleet size of the Lycoming and Continental is many times larger, 200 times (?) more than the alternative engine fleet, especially in the high performance fixed wing plane category.
There are 66 times more registered Lyc 320/360's than Subaru engines with the FAA and only 2 times the failures. HOURS FLOWN? I can only imagine that the Lyc flys more but that is hard to prove.
Do all the other Lyc's count in the statistics: 235, 290, 480, 540, 720 and radials count as well? There are near 65,000 to 80,000 Lycs on the books (I think) with the FAA, not including turbines. How many are flying I don't know, but the 80 core failures for all certified engines (Lyc, TCM, Frank, P&W, Wright.....) over approx 70 years is about one a year.
Many of the Subarus are the lower power E85's used on Gyrocopters, but you don't read about all engine failures in the NTSB database, since many just Gyro down; however many did make the list of 42 accidents for Subaru powered "planes".
It is safe to say Lycoming has no (or few) cooling lines, belt or electrical causes of power loss in the data base. Belts took down at least one or two Alt engine planes, since they drive "internal" timing or cams. I did not check the Lyc but belts tend not to be critical as in engines with a belt driven valve train.
Conclusion: Draw your own, But I don't see a systemic problem with Lycoming or Continental reciprocating lower end or valve train. Both Continental and Lycoming went through a Crank production QC debacle at one point in time. You can see from the data the Continental crank problem on the C210's, early 1990's, and on the Lyc, late 90's, when their crank issue appeared. There are a handful of crank failures due to manufacture defects. If not for this transient QC issue, there would be about 5 less crank failures. Some of the above crank/rod failures where due to prop strikes or poor maintenance clearly, a cause and affect. I did not remove them from the count. The lesson is proper maintence and overhaul.
Although my search only went to 1985 it included all the planes in service made before than till now. If you parse the data even further you will find may be a dozen real holly failures out of the blue or due to manufacture failures for ALL aircraft engines. That ain't bad. Against the fleet size and time in service (since 1960) that's acceptable.
Fleet size is hard to pin down but from a "FAA registered" data base got the following: Lyc 320/360's - 40,000 (at least 65k for all Lyc horz recips), Subaru - 609, Ford - 121, Mazda - 4 (sounds low), Volkswagen - 1,235, Chevy (none listed).
Using the NTSB data I tried to find the answer. Of course fleet size and hours of utilization is hard to pin down. This is how I attacked it.
For the alternative engines I searched for the engine name and variations. Than I went through each probable cause to determine if the engine was the cause and what part.
I eliminated any Undetermined, WX, Pilot Error or Airframe issues, so if the math does not add up that is why.
For the Lycoming I could not just type that in. So I searched the reason or probable cause field with key words such as: Crankshaft, Connecting Rod, Rod Cap, Bearing - failure, fatigue and fracture. Than I went through the results and eliminated other engines and as with the alternative engines, undetermined, WX, pilot error and airframe. The data base seems to go back to 1985, although I searched back to 1970. So assume this is 22 years worth. If it was not in the database I did not included it. No claim of perfection her just a good broad swipe.
Accidents due to internal Engine Failure
Lycoming (all)
32 total accidents
17 crankshaft failure, fatigue & Fracture, 1 experimental
15 rod, rod cap, rod bolt, failure, fatigue & Fracture, 2 experimental
[Note: maintence or improper engine assembly, e.g., under torquing rod bolts was included. There where at least 6 due to improper maintenance or manufacture defect. 3 failures in Experimental's.]
Breaking the "32" down to just typical "RV" engines failure/fatigue/fracture:
360s 4 crank & 4 rod failure, fractures and fatigue - 8 total
320's 1 crank & 1 rod failure, fractures and fatigue - 2 total
235's 0 crank & 1 rod failure, fracture and fatigue - 1 total
Subaru
42 accidents
16 pilot error
8 Undetermined
18 total ancillary & mechanical failures:
12 Ancillary
1 Vapor lock
1 Cooling lines
1 Waste gate servo
2 Fuel / Pump failure
7 electical / ignition
6 mechanical
1 PSRU failure*
1 Bearing failure
1 Belt timing gear
2 valve train or exhaust valve
1 Connecting rod failure over temp
*Consider PSRU as part of the engine.1 Vapor lock
1 Cooling lines
1 Waste gate servo
2 Fuel / Pump failure
7 electical / ignition
6 mechanical
1 PSRU failure*
1 Bearing failure
1 Belt timing gear
2 valve train or exhaust valve
1 Connecting rod failure over temp
Chevrolet / General Motors
13 total accidents and (1) major engine failure, (2) fuel related and (1) reduction drive.
The following Chevy or GM engines used: 5-V8, 6-V6, 1-4 cyl, 1-corvair
Mazda
Total 7 accidents: (1) Cooling, (1) Lube System, (1) exhaust/prop, (3) Carb/Fuel sys
Volkswagen
36 total accidents: (2) cranks, (1) lube system, (3) Ignition, (3) Carb/fuel
Ford
Total 8 accidents: (1) Cool, (1) Lube external, (1) Ignition, (1) Fuel (carb ice)
(2) Model-A's, (6) V6
*********************************************************
Totals - accidents due to core engine failure
Lyc 32 (11 for 235, 320 and 360's only)
Subaru 6
Chevy 1
Mazda 1
VW 3
Ford 0
The above ignored electrical, cooling, ignition, turbo, timing and fuel issues. Of the alternative engines, adding the electrical, cooling, fuel and misc, you would have this.
Total accident due to loss of power core + ancillary
Subaru 18
Chevy 4
Mazda 6
Ford 4
VW 9
The higher number for the Subaru & VW is no doubt related to a larger fleet size. It is clear that the ancillary items on alternative engines, electrical, cooling, fuel and misc cause more loss of engine power than rods and cranks. The VW had almost as many accidents as the Subaru, but most where undetermined, pilot or other.
This is not a PERFECT cut at it, only a broad brush approach. I could have missed other "core" causes of loss of power, but a good faith effort was made.
Of all the Lyc powered Experimental planes, there where only (3) hard engine failures.
I did not search for fuel issues, starvation, carb ice, vapor lock and so on with the Lyc but there are 100's of fuel related accidents, but I did not include fuel starvation or carb ice with any of the above.
The fleet size of the Lycoming and Continental is many times larger, 200 times (?) more than the alternative engine fleet, especially in the high performance fixed wing plane category.
There are 66 times more registered Lyc 320/360's than Subaru engines with the FAA and only 2 times the failures. HOURS FLOWN? I can only imagine that the Lyc flys more but that is hard to prove.
Do all the other Lyc's count in the statistics: 235, 290, 480, 540, 720 and radials count as well? There are near 65,000 to 80,000 Lycs on the books (I think) with the FAA, not including turbines. How many are flying I don't know, but the 80 core failures for all certified engines (Lyc, TCM, Frank, P&W, Wright.....) over approx 70 years is about one a year.
Many of the Subarus are the lower power E85's used on Gyrocopters, but you don't read about all engine failures in the NTSB database, since many just Gyro down; however many did make the list of 42 accidents for Subaru powered "planes".
It is safe to say Lycoming has no (or few) cooling lines, belt or electrical causes of power loss in the data base. Belts took down at least one or two Alt engine planes, since they drive "internal" timing or cams. I did not check the Lyc but belts tend not to be critical as in engines with a belt driven valve train.
Conclusion: Draw your own, But I don't see a systemic problem with Lycoming or Continental reciprocating lower end or valve train. Both Continental and Lycoming went through a Crank production QC debacle at one point in time. You can see from the data the Continental crank problem on the C210's, early 1990's, and on the Lyc, late 90's, when their crank issue appeared. There are a handful of crank failures due to manufacture defects. If not for this transient QC issue, there would be about 5 less crank failures. Some of the above crank/rod failures where due to prop strikes or poor maintenance clearly, a cause and affect. I did not remove them from the count. The lesson is proper maintence and overhaul.
Although my search only went to 1985 it included all the planes in service made before than till now. If you parse the data even further you will find may be a dozen real holly failures out of the blue or due to manufacture failures for ALL aircraft engines. That ain't bad. Against the fleet size and time in service (since 1960) that's acceptable.
Fleet size is hard to pin down but from a "FAA registered" data base got the following: Lyc 320/360's - 40,000 (at least 65k for all Lyc horz recips), Subaru - 609, Ford - 121, Mazda - 4 (sounds low), Volkswagen - 1,235, Chevy (none listed).
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