Airplane engines are those noisy beasts that assault our eardrums whenever we choose to fly. We are accustomed to the noise and have grown used to the peculiar rhythms of various stages of our flight. By reason of an unusually effective marriage of technological prowess with regulatory oversight, airplane engines have phenomenal safety records.
When something goes amiss with an airplane engine, it is big news. It doesn't happen very often. Human lives are usually at stake. Whenever I hear of such an incident, my first reaction is to pray that no one was injured. My second is to inquire as to the cause.
On this secondary consideration of cause, as a General Electric (NYSE:GE) shareholder, I always listen for information as the manufacturer. I am sensitive to any trace of GE involvement, be it as manufacturer of the engine, a replacement part or in some service capacity.
Jet engines are supposed to be seen. They are expected to be heard. They are not, however, supposed to be in the news in connection with any scary incident.
Jet engines are exceptionally adept at meeting their safety mandate. They log millions upon millions of miles living up to the expectation of reliable, carefree (from airline passengers' perspective) performance. Certainly, it is a truism as regards aircraft engines, in the overwhelming majority of cases, that no news is good news.
GE's CF6 engine is currently in the news for reason of catastrophic failure.
The news cycle of late has been consumed with overtly political news or subjects that have definite political overtones, such as terrorism and urban policing. It is not easy for other subjects to make it to the fore. This past weekend, a catastrophic engine failure broke through this political blockade.
Billowing black smoke and passengers sliding down the emergency slide were enough to assure prominent news coverage for Friday's catastrophic engine failure on a recent flight heading out from O'Hare. Blessedly, the failure occurred before the plane was in the air. There were no fatalities; the only injuries were minor.
The engine failure was severe enough not only to cause the fire and evacuation, it actually shot shrapnel from the engine for several thousand feet.
Initial news reported that the plane was a Boeing (NYSE:BA) 767. I checked and learned that both GE and Pratt and Whitney supplied engines for the 767. Subsequently, SA reported that in this case, the engine was a GE engine, part of the CF6 family of engines.
This was not what I wanted to learn, but I was relieved to see that GE had not been maintaining this engine. The SA community quickly pitched in with numerous comments, many of which were quite helpful to put the issue in context. This is one reason why I always cheer when SA elects to contribute a news release on a breaking story that interests me.
Experienced hands know it is far too early to speculate as to the ultimate cause of the failure.
One thing that is quite clear from the comments to the SA report is that it is way premature to start assigning an ultimate cause for this failure. The FAA has worked out a thorough and reliable process for discovering causation in such matters. The complexity of the subject matter dictates that this process is quite lengthy and drawn out.
In other words, we must "cool our jets" before trying to resolve this matter. The particular failure at issue has already proceeded further in a shorter time than is typical for such incidents. The National Transportation Board (NTSB) has already issued a preliminary statement assigning a particular mechanical part they believe is involved in this incident. According to an October 29, 2016 UPI report:
... Investigators at the National Transportation Safety Board on Saturday released the results of a preliminary investigation of the engine failure that caused an American Airlines plane to catch fire, showing a piece of the engine was flung nearly 3,000 feet when it exploded.
The incident, which caused American Airlines Flight 383's engine to start on fire as it was attempting takeoff at Chicago's O'Hare International Airport, did not cause any serious injuries.
The NTSB said in a briefing Saturday evening a preliminary investigation showed the stage 2 disk of the engine's high pressure turbine failed. The engine part was located in a UPS warehouse located more than a half-mile from the accident site.
The failure caused the plane's engine to explode and catch fire and the pilots immediately aborted takeoff. Passengers were forced to use emergency chutes to escape the plane.
The NTSB obviously cannot yet opine as to the precise cause for this failure. There are a number of seemingly obvious possible causes. It could be design issues, material failure, maintenance failure or something could have been sucked into the engine. Time will pass and the NTSB will issue its report.
Accepting this received wisdom as true, I have nonetheless scratched my curiosity itch on this particular issue.
The possibilities are profuse, particularly for those of us who lack first-hand knowledge sufficient to winnow the remotely possible from the highly plausible. This article seeks to examine the situation and to ferret out the more plausible scenarios from those less so. Hopefully, I can draw out suggestions from the SA community which will augment my suggestions.
I am starting my inquiry by looking into the storied CF6 engine family. Perhaps there are some family secrets that exist. My first stop is GE's website. Here one learns that the CF6 engine family has a 40-year heritage. It comes in six different models.
It is certified to power 13 different airplane types and has logged nearly 400 million flight hours. The Qantas plane that shows at the beginning of this article is a long-distance champion. Equipped with four CF6 engines, the Boeing 747-400 flies nearly 8500 miles non-stop from Dallas to Brisbane, Australia. The CF6 has clearly proven its merit.
This said, it seems we can pretty much rule out the notion that the CF6 suffers from a basic design flaw. It seems more likely that any problem relates to maintenance or replacement parts or perhaps some experiential problem occurring with the particular CF6 that failed. Now I'm talking my book. I like where this is taking us.
I am tempted to leave it at that, but things are never that easy. When I leave GE's web site, I find no smoking gun suggesting that the FX6 is defective. However, I do learn that what I intuitively suspect is, in fact, true. The CF6 has not enjoyed its nearly 400 million flight hours entirely free from incident. There have been prior failures - no surprise there.
In particular, the one issue which drew my attention was a 2010 FAA airworthiness directive focusing on the CF6-45/50 engine. This is a different model from the one at O'Hare. However, the NTSB issued:
... two urgent safety recommendations to the FAA. The first asks that the FAA require operators of aircraft equipped with a particular model engine to immediately perform blade borescope inspections... of the high pressure turbine rotor at specific intervals until the current turbine disk can be redesigned and replaced with one that can withstand the unbalance vibration forces from the high pressure rotor. The second asks the FAA to require the engine manufacturer to immediately redesign the disk.
It may be that this 2010 issue has no bearing whatsoever on the O'Hare incident. Nonetheless, it points to a possible avenue of inquiry. It also provides a point of discourse that one of SA's more technically talented members may run with.
GE's Aviation division is one of the company's very brightest. The fact that it is so seldom in the news is a good thing. The recent O'Hare engine failure was a rare exception to GE Aviation's salutary regimen of silence.
I am hopeful that over time its main significance is as an object lesson as to why airlines should retain GE to maintain their engines. Surely, GE engineers and technicians armed with Predix will do a better job of keeping engines in peak operating condition than airline employees or third-party contractors. The marketing pitch writes itself.
Nonetheless, silence is still better than NTSB inquiries. In this case, the silence is broken. All appearances are that the CF6 will survive the inquiry unscathed. Such is my operating assumption. What is your thought on this matter?
Disclosure: I am/we are long GE. I wrote this article myself, and it expresses my own opinions. I am not receiving compensation for it (other than from Seeking Alpha). I have no business relationship with any company whose stock is mentioned in this article.