Deregulation was without a doubt a major factor in the retirement of the 707s and DC-8s. In the new cutthroat era of US aviation history airlines needed to be more efficient than ever to combat new start ups and build up their new hub and spoke networks. In addition the introduction of aircraft noise stages in 1977 by the FAA put a finite life on many of these aircraft as 707s and DC-8s fell within the noisiest Stage 1 category. Hushkitting large fleets of early 707s and DC-8s simply wasn't going to be cost effective.
In fact noise was already an issue in the early 1970s and Douglas made various retrofit kits available to try and lessen the issue with the especially noisy series 60s. By early 1975 Douglas had identified several options to decrease the sound of a DC-8. First there was the possibility of a new version of the JT3B engine, but that would take 3 years to develop and cost about $6 million per plane. The alternative was to use de-rated CF-6 engines (as used on the DC-10) but these were even more expensive at $10 million per ship set and too powerful. In July 1975 General Electric offered the newer CFM-56 but in the absence of clear guidelines from government the airlines weren't keen to proceed.
In March 1977 things changed when the rules were set so that all aircraft weighing over 75,000 Ibs must meet Stage 3 regulations by January 3, 1985. This was a tough call as even early DC-9s, 727s, 737s and 747s didn't meet Stage 3 let alone 707s and DC-8s. That year a new company, Cammacorp, was setup - mainly by ex-Douglas staff. They agreed a deal with General Electric and SNECMA to market the CFM-56 engine for DC-8s. Despite McDonnell Douglas' initial reluctance to get involved by May 1977 it was negotiating with two airlines for a DC-8 re-engine. The two candidates were the CFM-56-1, de-rated to 22,000 Ibs of thrust, and the 19,000 Ib JT8D-209. The latter was to be the engine for the MD-80 series.
The JT8D had the advantage of not needing new pylons for DC-8-62/63s but in most other ways the CFM was the better engine. It had substantially reduced fuel burn (21% to 11.7%), shorter field length requirements, better range, higher cruise altitude and was quieter. It did need completely new pylons but these benefitted the DC-8-61 by removing the above wing portion of the pylon, as in the 62/63.
Delta was the first airline to admit looking at the proposed re-engining however it was United that surprised the industry on March 29, 1979 when it placed a $400 million order to upgrade its 29 DC-8-61s with CFM-56-1 engines. United had initially favoured the JT8D but had been convinced to take a second look at the CFM by Flying Tigers. Cammacorp entered into an agreement with Douglas for it to provide all engineering support and undertake the conversions at its Tulsa plant.
The first aircraft to undergo conversion was United's N8093U, which arrived at Tulsa in October 1980. It was then that the change in designation from 61,62 or 63 to 71,72 or 73 was announced. The conversion period was longer than originally hoped and the first DC-8-71 missed the 1981 Paris Air Show and didn't fly until August 15. The FAA awarded type certification to the series 71 on April 13, 1981. The first aircraft delivered to United was N8092U on May 10, 1982. She went into service between San Francisco and Portland six days later. After one year United was averaging 16 hours a day of operations with the Super 70 fleet and dispatch reliability was running at 99.86%. United 71s were also fitted with the new widebody style interiors with enclosed overhead luggage compartments.
The DC-8 re-engine programme was a success for all concerned with 110 aircraft modified. More may have been rebuilt if it weren't for the US government's extension of noise restriction deadlines meaning that aircraft only needed to be Stage 2 compliant by January 1986 and Stage 3 compliant only by January 2000. This ruling favoured cheaper Stage 2 hushkits. In addition fuel prices had dropped and the conversion price had risen to $15 million per plane.
United got a good decade of extra service out of their DC-8-71s. The entire fleet was sold to GPA leasing in 1989 but was leased back for a few more years. The final service was operated in late 1991, fittingly between San Francisco and Kona, Hawaii. As late as December 1989 the United timetable still showed DC-8-71s operating a variety of trunk routes:
DEN - EWR HNL IAD LAX ORD PHL PDX SAN SFO
IAD - BDL DEN EWR ORD SAN SFO
LAX - EWR ORD PHL
ORD - BOS CLE CUN DEN EWR IAD LAX MIA PDX SFO SJO SEA
SFO - DEN, EWR IAD KOA LAX PDX SEA
The DC-8-71 conversions were certainly good value for money and the type would go on to have long careers as freighters after Delta and United were done with them. This is the last part of my posts on United's DC-8s but there may yet be more on the DC-8-71...
Airliners.net. Final UA DC-8 Routes
Waddington, T. Great Airlines Series: Volume 2 - Douglas DC-8
Cearley, G.E. United: The Main Line Airway
Aeromoe's United Fleet
10/11/2016 08:11:09 pm
I was always saddened that the 707 more or less disappeared from USA commercial skies by the late 80's. Maybe you can answer a question. I read that one reason that the 707 wasn't widely re-engined was because its shorter landing gear made fatter high-bypass ratio engines hang too low. Yet I see KC-135's that have been so re-engined. What gives?
18/5/2019 11:12:00 pm
The 707 actually was re-engined, with the same CFM56-2 used on the DC8 Super 70's. N707QT was the sole prototype for the proposed 707-700 series, flying in 1979:
Miles W. Rich
24/10/2017 03:11:18 pm
When American announced the mass retirement of their 707-123B, 323B, and 323C fleet in 1981, effective in September of that year, TWA was the only domestic airline besides American still flying four engine narrow body jets. United retired their JT-4 powered non fan DC-8-21 in January 1978, and their JT-3D fan powered DC-8-51/52s in 1980. Delta retired their DC-8-51 fleet during 1979 and 1980. Eastern had dumped all of their DC-8s including their Super 61s and 63s in the mid to late 70s. Western dumped their 720-047Bs, and 707-347Cs in 70 and 80, Northwest dumped all of their 720-051Bs, and 707-351B/Cs by 1977, Continental and Braniff dumped their in the early to mid 70s, although Braniff did operate a few used DC-8-51s in 1978-79 while they waited for 727-227As to be delivered after their ill advised post deregulation massive expansion, National said goodbye to their DC-8s including their two Super 61s by 1974. Pan Am also kept a few 707s for their thinner international routes into 1980 when they were retired. American had just expanded their DFW hub in June to compete with Braniff on every former BN proprietary route so they "needed" the 707s to cover some of their schedule and when they announced the grounding, they were short of aircraft until they received some used 727-227As from Braniff which was already struggling, given the 2nd oil price shock after the Iranian Revolution.
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I'm Richard Stretton: a fan of classic airliners and airlines who enjoys exploring their history through my collection of die-cast airliners. If you enjoy the site please donate whatever you can to help keep it running: