The cause of the engine failure in N5841 was a broken crankshaft at the #1 cylinder which is at the back of the engine. This reportedly is the point of highest stress on the crankshaft. Continental will conduct a metallurgical analyis of the part to see if they can determine the cause of the fracture. Since the prop continued to windmill the broken parts ground against each other so you can’t tell much by visual inspection.
A new engine has been put in the plane and it has been flown to Duluth for a final checkup. This plane also had excessive tire wear at 100 hours.
What’s likely to be causing this excess tire wear?
When you say excessive tire wear…
Are you taking in concideration that this is a rental airplane? How many different pilots have made landings in the 100 hours?
How many of those only were concern about the hobbs meter?
Are you concedering that this is a free nose wheel? How many people know how to properly taxi using a free nose wheel.
Here are my thoughts.
Training or rental will be abused.
There is much (much) more touch and goes or stop and go done on a checkout than anyone of us will be doing with their own airplanes, so this will cause much more wear.
Last, I am sorry for writing so much… but just had to say my 5 cents worth.
Free nose wheel, are great from a pilot and maintenance view
This plane also had excessive tire wear at 100 hours.
The cause of the engine failure in N5841 was a broken crankshaft at the #1 cylinder which is at the back of the engine.<
For the experienced pilots in the group: is this a familiar category of engine failure? Or is this a departure from what you’re used to hearing about, as a reason for an engine to stop in mid-air?
By analogy: when we hear of a vacuum system failure, we think: “thank God mine hasn’t failed yet.” But if we hear that a turn coordinator has failed (without a general electric breakdown), we think: “that’s odd.” Is a crankshaft a likely failure point, similar to a vacuum system? Or does this strike you as odd?
Also: is there any reason to think that there is a connection between this engine’s failure, and its failure in a Cirrus? Ie, anything about the mounting, loads, stresses, or anything else about the Cirrus configuration that would make the engine more vulnerable? Or is it more likely that the plane was the innocent vehicle for a mishap that would have befallen this engine wherever it was?
Advice from those who’ve heard about engine failures over the years highly welcomed. Thanks, Jim F.
SR20 Gang,
I am about to have my tires changed over at about 160 hours. I was alerted by Walt to the possibility that the tires installed by Cirrus combined with the installed camber was likely to produce a short tire life. The bottom line is that Cirrus specified a fairly low grade tire and installed the tires(at least on mine and Walt’s) at a higher camber than necessary (producing excessive wear). I cannot fault Cirrus, like any manufacturer, they are inclined to install cost effective components, I just wish I had had offered(and I am sure Walt would agree) the option to spend a few additional dollars on higher quality tires. For low number position holders, you may want to ask the question about upgrading the tires.
Additionally this aircraft is more difficult than most to learn how to land. As I have said in prior coorespondence it lands pretty flat and requires a lot less flare than a C-172 or PA-28. If excessive flare is applied, a hard (tire crunching) landing can result. It does not surprise me at all to hear that a SR20 trainer is experiencing pre-mature tire wear.
This is an excellent aircraft for recreational and training flight, but its unique (and in my opinion superior) characteristics take a little time to get used to. The likely scenario is that the SR20’s in club fleets will be relegated to the experienced pilots due to the cost of the airframe, but I must say that new or low hours pilots are likely to take to the aircrafts flight dynamics more quickly than higher hours pilots. This aircraft simply flies and handles better than the planes we were trained on, making the challenge of dealing with the inadequecies (sp?) of older airframes much less important and the transition to the SR20 a little more difficult.
I am waiting for some nice weather so I can get my bird back up in the air.
Christopher
P.S. I am replacing my tires more as a preventative issue than due to actual visual wear. I land at Class B airports too much to risk the wear related blow out. Logan is pretty particular about not wanting to tow singles off of 4R or 4L on a busy afternoon (I could cost them thousands).
After reading Chris’s message I realize that SR20 #1,2 and 8 have had tire problems in the first 200 hours. I agree that better tires should be an option. Better yet, in view of the value of the airplane and its performance, better tires should be standard. To spend $200,000 on an airplane and save $200 on the tires doesn’t make much sense. It is also difficult to check the tires on preflight because of the pants.
SR20 Gang,
I am about to have my tires changed over at about 160 hours. I was alerted by Walt to the possibility that the tires installed by Cirrus combined with the installed camber was likely to produce a short tire life. The bottom line is that Cirrus specified a fairly low grade tire and installed the tires(at least on mine and Walt’s) at a higher camber than necessary (producing excessive wear). I cannot fault Cirrus, like any manufacturer, they are inclined to install cost effective components, I just wish I had had offered(and I am sure Walt would agree) the option to spend a few additional dollars on higher quality tires. For low number position holders, you may want to ask the question about upgrading the tires.
Additionally this aircraft is more difficult than most to learn how to land. As I have said in prior coorespondence it lands pretty flat and requires a lot less flare than a C-172 or PA-28. If excessive flare is applied, a hard (tire crunching) landing can result. It does not surprise me at all to hear that a SR20 trainer is experiencing pre-mature tire wear.
This is an excellent aircraft for recreational and training flight, but its unique (and in my opinion superior) characteristics take a little time to get used to. The likely scenario is that the SR20’s in club fleets will be relegated to the experienced pilots due to the cost of the airframe, but I must say that new or low hours pilots are likely to take to the aircrafts flight dynamics more quickly than higher hours pilots. This aircraft simply flies and handles better than the planes we were trained on, making the challenge of dealing with the inadequecies (sp?) of older airframes much less important and the transition to the SR20 a little more difficult.
I am waiting for some nice weather so I can get my bird back up in the air.
Christopher
P.S. I am replacing my tires more as a preventative issue than due to actual visual wear. I land at Class B airports too much to risk the wear related blow out. Logan is pretty particular about not wanting to tow singles off of 4R or 4L on a busy afternoon (I could cost them thousands).
When I say excessive wear I mean down to the cord. All the factors that you mention would cause more wear than if you made one landing every four hours of flight time. However, the original equipment tires are not the highest quality available and Cirrus will now re-align the tires. This is the second SR20 that has had an alignment problem.
When you say excessive tire wear…
Are you taking in concideration that this is a rental airplane? How many different pilots have made landings in the 100 hours?
How many of those only were concern about the hobbs meter?
Are you concedering that this is a free nose wheel? How many people know how to properly taxi using a free nose wheel.
Here are my thoughts.
Training or rental will be abused.
There is much (much) more touch and goes or stop and go done on a checkout than anyone of us will be doing with their own airplanes, so this will cause much more wear.
Last, I am sorry for writing so much… but just had to say my 5 cents worth.
Free nose wheel, are great from a pilot and maintenance view
This plane also had excessive tire wear at 100 hours.
is this a familiar category of engine failure?
Familiar, yes, but worrying. It is definitely not the type of failure you would expect in a near-new engine, unless the plane had suffered a prop-strike or was used for aerobatics. The crankshaft is arguably the most critical single component in an engine, and should be expected to be pretty much bulletproof.
There was an AD issued in '97 (I think) that required the cranks in Continental IO-360 and TSIO-360 engines replaced with the newer VAR (vacuum arc remelt - basically a superior manufacturing process) type. This was due to a number of broken cranks in these engines. The IO-360 in the SR20, being a new engine, would have had the new type crank.
There are some differences between the SR20’s IO-360 and older models (it’s lighter, to start with). Whether this is significant we will have to wait and see.