Jumpseat: Checking Under the Hood

** The first PW1100G-JM engine for the Airbus
A320neo begins testing.**

The opportunity for me to touch and feel the inner workings of the machinery providing the thrust that keeps me airborne had always seemed an interesting proposition. With Pratt & Whitney (P&W) practically in my backyard, that possibility became a reality.

On the aviation-is-a-small-world front, I was fortunate to have established a relationship with a P&W engineer who had purchased a Piper Arrow from my airplane neighbor and friend Don Larson. That relationship was of great assistance in granting me a factory tour and an intimate glimpse under the hood. It also afforded me the opportunity to see the company’s latest flagship product — the geared turbofan engine. The engine would soon be attached to the wings of an Airbus A319neo or A321neo (new engine option) near me — well, maybe ... if my airline makes the choice.

The P&W property is located in an area of Middletown, Connecticut, that is deliberately secluded and off the beaten track — but not for reasons you might think. The property and most of the original buildings were once owned by the U.S. government. Its purpose? To build a nuclear-powered jet engine. The engine didn’t quite materialize. By 1962, the United States had gotten distracted with a different type of nuclear issue taking shape in Cuba. P&W bought the facility shortly thereafter.

The architecture is 1950s-austere but very functional for P&W’s purposes. Inheriting the tar-soaked, wood-block floors proved problematic, however. The floor hides dropped parts. The process of removing the old floor and replacing it with concrete that is painted gray is ongoing. The gray and the concrete do a better job of revealing escaped parts.

The factory is approximately 2.2 million square feet. For obvious reasons, it is climate-controlled. Space is divided according to the engine type that demands the highest production rate. A change in engine production requires millions in capital investment to readjust the assembly line. Space is also divided into small, medium and large commercial engine assembly. And the military has its own area, hence their not allowing my Nikon to accompany me.

Rolls-Royce and Pratt still share half the production of the V2500, the engine that powers the A319, A320, A321 and MD-90. Rolls-Royce ships parts to Pratt and vice versa. Rolls takes credit for the odd serial numbers and P&W for the even ones.

Similar to Boeing’s procedures, Pratt has adopted a very safe and pragmatic building process. Each engine has a given number of assembly stations. Each station is supplied with multitiered carts. The carts contain parts in sealed bins. Color-coding is utilized to match engine parts with the appropriate engine. Numbers designate each assembly station.

An extra bolt remaining or a bolt missing is not treated with a simple shoulder shrug. Pratt considers it a serious matter. If a mechanic experiences either situation, assembly of that engine ceases. An independent inspection is required.

As I took in the sights of the tour, I couldn’t put a finger on it, but something was missing. It wasn’t until the conclusion of the visit that Jim Speich, director of marketing and my tour guide with an engineering background, gave me the answer. Toolboxes were nowhere to be found. Not one sticker-laden, towering Snap-On toolbox was anywhere in sight. Instead, the mechanic’s sacred container of his most valued professional investment had been replaced by a package sealed with plastic wrap. The package contains all the specific tools required for a given assembly station.

To save wear and tear on a mechanic’s back and to prevent awkward reaching situations, the engine is assembled vertically on top of a platform that lowers into the floor, allowing easy access to any section. An iris is utilized to isolate a particular section. Newer platforms make use of hovercraft technology. Air pressure floats the platform. The entire engine assembly can be moved almost effortlessly to the next station.

Most of P&W’s mechanics have 25 years of experience with the company and are over the age of 50. A younger workforce is slowly replacing the veterans. New mechanics are hired with the qualifications of either an A&P certificate or six to 10 years of military experience. Once hired, a new mechanic is required to complete a six-month internship. The internship is divided into two three-month periods under two different veteran mechanics.

My other tour guide (who had the energy of two V2500 engines), Rosario “Riz” Rizzo, manager of public affairs and a former mechanic, indicated that the highest-paid mechanics are the ones that run the 3½ hours of required testing for each newly assembled engine. Why are they the highest paid? The company has the most money invested in the completed product. Inexperience has the potential to be expensive.

As my tour progressed, I was anxious to see the PW 1100G-JM, still in the block phase. The engine will be installed on the A319, A320 and A321 as part of Airbus’ NEO program for those airlines that choose P&W. In various ratings of thrust horsepower from 23,500 to 32,100 pounds, the engine will also be installed on C-series Bombardier aircraft, the Embraer 170/190 and a newly designed Russian airliner. The test versions have flown aboard an A340 in addition to P&W’s specially equipped 747s.

Geared technology is not a new concept. The technology has been used on smaller engines for some time, but never applied to large turbofans. Without getting into an area best explained by my colleague Peter Garrison, the premise of GTF is to use gearing in order to slow the rotation of the fan such that the rpm is much lower (in this case, slowed to a third of the speed) than the engine core. More air is used to drive and cool the engine. This provides for increased fuel-burn efficiency and less noise. And Pratt claims that emissions are reduced.

Jim indicated that he had worked on a gearing system 20-plus years ago. But the 600-pound weight of the gearbox made the design impractical. Today’s updated materials have reduced that weight to 250 pounds. And instead of individual blades that fit into precision-measured slots for both the turbine and compressor, integrated blade rotors are utilized, decreasing the engine core weight even further. The entire rotor, blades and all, is a solid unit. Absent are the tinkling sounds made when the engine windmills on the ground.

The only individual blades are located in the turbofan itself. The blades have an artsy aerodynamic shape not yet seen on any jet engine today. The leading edges are titanium. The blades themselves are coated with a vinyl-like material. I asked whether composite materials were used for additional weight savings. Nope — instead the blades are an aluminum alloy, much better for FOD resistance.

Although the size of the 1100G is the same for the Airbus series, the engine is rated with different thrusts just by virtue of changing a computer chip. Approximately 3,000 sensors are installed to monitor almost every parameter. All of this new technology is transparent to the pilot. The only addition to warning systems is a chip detector for the gearbox.

As of this writing, the FAA has just approved the 1100G for regular production. One of the required final approval tests involves setting an explosive charge under a fan blade root. The objective is to determine engine integrity after a catastrophic failure. For certification, the engine case must contain the debris. In addition, the engine must automatically shut itself down without operator assistance. The 1100G passed with — sorry — flying colors.

I viewed one of the test engine casings. The engineers were able to predict, within about five degrees, where the first strike damage was to occur. The damage proved minimal. The honeycombed sound-suppressing material was wounded with a few cuts and tears but only in one area. If that engine was on an airplane that I was flying, I am relatively certain that no adverse flying effects other than the effects of the actual failure would have occurred.

Anybody who flies an airplane should take the opportunity to tour an engine assembly facility. Not only have I gained a greater appreciation for the reliability of the powerplant that keeps me airborne, but I have confidence that the men and women who design and build such products are satisfied with nothing less than perfection. I really liked what I saw under the hood.

Les Abend
Les AbendAuthor
Les Abend is a retired, 34-year veteran of American Airlines, attempting to readjust his passion for flying airplanes in the lower flight levels—without the assistance of a copilot.

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