CFM we have a problem. The all Boeing Max put its eggs in the CFM Basket which now faces a 5% short fall as reported by multiple news sources. The all-knowing reading techno junkies are now asking "Winging It to explain its way out of this mess Ollie". I can't and I won't explain the predicament Boeing now finds itself under. A 800 hundred pound Gorilla hung under the MAX wing is a show stopper in the single aisle order book as it would make the 737 Max more like a NEO in performance. If a person gets 20 miles per gallon with its loaded vehicle, a reduction of 5% directly results to a 19 mpg actual performance outcome, using the same operational conditions. A 20 gallon tank then has a range of 380 miles instead of 400 miles. A CFM version engine has a 5% short fall then it translate into these roughed out numbers. A person can achieve a 5% short fall from tire pressure. CFM has to find the right tire pressure.
Apply a 5% penalty to everything in with simplistic analysis.
- 4,000 mile range Drops to 3,800 mile range.
- Seat cost per passenger rises by 5%.
- Fuel Cost rise incrementally by 5% no matter the per gallon price.
And so forth...
The actual percentages may vary per category as they are measures against the whole of the aircraft performance and operational costs. The main thing is that CFM has to solve its underestimation by 5% it sold Boeing in the next two years. The only Olive branch offered Boeing is,
"We have two years to make it right!"
The question quickly shifts, can they really make it right this late in the CFM 1B level of development? Second place is for losers when there are many options including PW and other projects. Boeing has been bitten by single sourcing its engines for the 737 using CFM only. An AA chapter on the Boeing campus is newly established for its Max executives.
CFM believes in the "Technological Fix Syndrome" (TFS) for all problems. The TFS does not work if all assumptions are flushed by the 5% shortfall. It cannot go back and start over from five years ago when it started the new CFM design implementations. It has a serious TFS issues, as it cannot invent its way out of the fix at this time. It must take the PIP pill once a month, by determining what it can improve within the hand it dealt itself. I must assume the 5% performance shortfall represents its base 1B engine even after considerable tweaking making its optimal performance level before any PIP changes are made.
The problem with PIP world is you have the base design to improve and not the whole of a fresh start. Making a pig fly only has some much it can improve upon within the constraints of a frozen design. Making a 5% performance recovery considers engineering Trickeration on an already improved design. In the meantime, the front office is searching for the team that said this engine is so good it could perform 5% better than what it just showed! Boeing bought it and now they are far out on the MAX limb spinning new assurances in area of billions and billions of dollars.
The answer is obvious, you are stuck Boeing, and CFM will have H*** to pay if they can't correct course.
You may ask how can Airbus with its CFM 1A get a 2% improvement compared with the Boeing version of a 5% shortfall. This part answer is found in the engine cowling and opening. The Airbus version is bigger at 71" across where the Boeing low ground clearance is a 61" opening. The larger the openings, the better the efficiency metrics are, as a general rule. The 777X will have the largest of all engine diameters. The Boeing 737 MAX did not stretch its landing gears taller due to in aircraft body space availability. This would be a major setback to the MAX project if they did so at the beginning, when they recognized a need for a few more inches of landing gear space for a taller landing stance. It would have accommodated a larger circumference engine cowling, and so forth. A larger engine opening would gain fuel burn performance.
The 737 Max sticking to engineering theme of compressing the body design, has reached a Max barrier of Body and Engine trade-off with its new CFM 1B engine currently on the test block. The engine needs help from Boeing design influences in order to Maximize the overall 737 MAX affect. The 800 pound Gorilla is not weight, it is specification within the concept of not having a larger engine opening in a single aisle class. CFM must now cram in a better performing engine, contained in a smaller space, by using adjunct engine PIPs. Just because they said they could do it at the outset, Boeing is calling them out to do it! Boeing is stressed.