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Best of Flashback Fridays: Origins of the Boeing 737, Part Two

Adventurer C

The subtitle for this week’s “Best of” post is “The 737-200 Advanced and Some Oddities”   The first time this was published on February 24, 2012, I remember being fascinated by an odd aircraft feature that I had not heard of before: the “Vortex Dissipator.” 

Considering that this has to do with making landings on gravel runways possible, I couldn’t help thinking that Brian probably had more than a couple of “between a rock and a hard place” puns running through his head while he wrote this post.  Of course, there’s quite a bit more here, so I hope you enjoy Part Two as much as I did.

The 737-200 Advanced and Some Oddities

In the previous edition, we briefly looked at the initial 737-100 and the more successful 737-200.  However, there were still areas that needed improvement with the basic -200, and these were corrected in 1971 with the introduction of the 737-200 Advanced.  While the size and basic design remained the same, the Advanced model offered significant performance improvements, and we have some great photos from Boeing again to tell the story.


The first 737-200 Advanced went to All Nippon Airways, better known today as ANA (the launch customer for the 787).  The Advance model had a redesigned and improved wing with a lot of the improvements dealing with the leading edge of the wings. 


The second Advanced aircraft went to the old Malaysia Singapore Airlines.  This airline would split in 1972 not long after this photo was taken into two separate carriers, Singapore Airlines and Malaysia Airlines.   This airplane, 9Y-BCR, will move to Malaysia Airlines.  In place of the basic model’s JT8D-7 or -9 engines, the Advanced model featured the more powerful JT8D-15 or -17.  This eliminated the need for the blow-in doors at the front of the intake, while allowing the aircraft to carry heavier loads at higher altitudes.


With the exception of our first three aircraft, all the future -200s that Southwest acquired directly from the factory would be the Advanced model.  Our three original airplanes, which were the basic model, only served with us for a very short period before they were replaced with Advanced examples.  We would, however, lease some additional basic aircraft from time to time.  In the photo above, one of our Flight Attendants went to Renton in 1977 to pose with N28SW, a 737-200 Advanced, which was under construction.


Airlines weren’t the only customers for the 737-200 Advanced, and the Air Force purchased 19 examples of a special variant, the T-43A, which was a trainer used to instruct navigators.  This model had only a few windows on each side of the fuselage.  Inside the cabin were navigator consoles for the trainees to use.  The T-43As were retired on September 19, 2010, at Randolph Air Force Base in San Antonio.


And, we close this installment with a look at one of the most unique jetliners, the 737 with a gravel kit.  Both Wien Air Alaska and Alaska Airlines operated these aircraft into the small gravel landing strips in remote Alaska villages.  (I think some are still being operated in remote areas in Canada.)   The photo above shows the amount of gravel kicked up during the landing process.  The -200’s clamshell thrust reversers are deployed, and we get a good view of the Advanced model’s redesigned wing leading edge.  Landings in the -200 were noisy under normal circumstances, so it makes you wonder what a gravel runway landing sounded like.


Above are some of the unique modifications that allowed the -200 to operate in this harsh environment.  Underneath the intake of each engine is a pipe, or a “Vortex Dissipator,” that protrudes under the front of the engine, and this nozzle blows engine exhaust down at the ground.  This breaks up the suction forces that would normally ingest gravel into the engine, without disturbing the performance of the engine.  Note the mismatched radome in the photo, and the aircraft wears a temporary registration number, N1786B, which is one belonging to the Boeing Company.  This indicates that the landing is some sort of a Boeing-sponsored trial.

Behind the nose gear is a gravel deflector.  This plate deflects any gravel that the nose gear kicks up, and it rides only a little more than three inches above the surface.  When the gear is retracted, the deflector rotates around the nose gear into a fairing built on the fuselage in front of the gear.  Other areas of the aircraft have simpler protective devices. 

The next part will look at a couple of airplanes in which Southwest played an important role, the 737-300 and 737-500.