Former Boeing Employee explains why the company didn’t develop the 757 instead of the older 737

‘As a testament of how good the plane was, most of the Boeing 757’s built were still in service as late as 2018,’ Glenn Tomchik, former Boeing employee who worked on the 757 program.

The twin-engine, medium-range Boeing 757 was up to 80 percent more fuel efficient than the older 727 jetliners it was designed to replace but retained the 727’s short-field capability. The 757-200 carried up to 228 passengers and had a range of approximately 3,900 nautical miles (7,222 kilometers).

The first 757 rolled out of the Renton, Wash., factory in 1982. On Mar. 29, 1991, a 757, powered by only one of its engines, took off, circled and landed at the 11,621-foot-high (3542-meter-high) Gonggar Airport in Tibet. The airplane performed perfectly although the airfield was in a box canyon surrounded by peaks more than 16,400 feet (4998 meters) high.

Yet, despite its remarkable capabilities, in late 2003, Boeing decided to end 757 production. On Apr. 27, 2005 in fact, Boeing concluded the 23-year run of the 757 passenger airplane by delivering the final one to Shanghai Airlines. The airplane was the 1,050th Boeing 757.

Why didn’t Boeing develop the 757 instead of the older 737? Why did they not envisage longer fuselage/higher capacity versions of the 757 like Airbus did of the A321?

‘I was working on the 757 program when its fate was being determined. The very simple answer to this question is that the 757 was too expensive,’ Glenn Tomchik, former Boeing employee who worked on the 757 program, explains on Quora.

‘The A320 was introduced in 1988 and the A321 in 1994. The 737 Classics (-300, -400, -500) had a few large shortcomings relative to them. First the range of 1500 miles vs A320’s 3000+ was too short for trans-US or trans-Europe flights. Also flying at .74 Mach caused air traffic problems with all the other aircraft flying at .8+ mach. The 757 had better range but was also significantly larger. Originally Boeing had planned to offer a 160 seat 757–100, but airlines weren’t interested and it was never developed.

‘So the answer in late 1993 to launch the 737 Next Generation (-600, -700, -800) which put on a new larger wing which increased fuel capacity, reduced drag, and allowed the plane to cruise over .8 mach. Updated engines and avionics made the 737NG very competitive, and it shared commonality for pilot training with the Classics. Over 7000 737NG’s were sold (vs. 1000 Classics), so obviously this wasn’t a bad decision. But the NG posed a problem for the 757: the 737 (and A321) could now perform 80% of the missions it was used for previously, but the 737 was 20% cheaper to purchase, even when adjusted for passenger count. For an airline the purchase or leasing costs account for half of their total costs. So why was this?

‘Most of the strengths of the 757 – such as high thrust-to-weight, 757/767 common flight deck and systems, and high engine clearance come at a cost (The tall gear was to keep flight deck the same height of the 767 allowing common pilot rating). The 737 and A320 have a pair of two wheel main gear, which limits their MTOW to about 200K (the A321’s). Four wheel trucks are used by the 757 as well as much larger A330’s and 787’s with up to 550K+ MTOW. Landing gear by volume is the heaviest part of the airframe and bigger gear requires more wheel well volume which adds significant weight to the fuselage. The wheel wells are two big holes in the most highly loaded part of the fuselage which requires a heavy keel and top and rear pressure bulkheads. Having a tall, heavy, and expensive landing gear puts it at a disadvantage to the smaller planes.’

Tomchik continues;

‘The 757 had a first generation super-critical airfoil wing that volume limited its fuel capacity and hence range. It would have been relatively easy to increase the gross weight (which was done for the 757–300) but to increase range would require body fuel tanks which has drawbacks (Boeing has never used them for commercial models), but the A321XLR uses them. Although many talks about the 737 was from the 60’s, the wing is actually newer than the A320’s and the fuselage was replaced with newer alloys and production methods.

‘Engine cost is directly proportional to thrust so the larger engines also drive up the cost. Engines in the 35–45K thrust range (the 757 size) originally were adapted from the three- and 4-engine airplanes (L1011, 747). By the 2000 time frame wide bodies engines were using much higher thrust and there was no new engine designs available to adapt to the 757. The CFM56 used by the 737 and A320 had an excellent performance record and no other engine came close to the production volumes which gave it good economies of scale.

‘Finally, the 757 was originally developed post-70’s oil crisis and prior to US airline deregulation, so the airframe was designed for light weight with less regard for cost.

‘By 2000, the 757 was only selling to a few markets that required its take-off performance (Uzbekistan), high capacity single-aisle (European charters), and Freighters (UPS, DHL). Production rates were cut to the point is was barely profitable, but the company remained committed to the program and was in the process of moving fuselage production to Wichita (where the 737 fuselage is built) when 9/11 occurred. Post 9/11 airlines were in serious trouble, several going bankrupt. Boeing slashed 737 production from 300/yr to 175/yr. The 767 only survived with the hope of the Tanker contract, and the 757 demand was too low. The A320 had a large portion of non-US airlines, and their production rate remained constant and for the first time surpassed the 737 production rates. The decision was made in 2002 to complete production of the remaining orders and production ended in 2004.’

Tomchik concludes;

‘Updated versions continued to be studied in later years, but to compete with the A321 it would need a significant performance advantage and all the changes required make the development costs too high. As a testament of how good the plane was, most of the 757’s built were still in service as late as 2018.’

Photo credit: Bill Abbott, Rolf Wallner and Riyad Filza via Wikipedia