CHECK SIX: The Rollout of the Boeing 367-80

14 May 1954: The rollout at Boeing's Renton Field facility of the aircraft that would change jet transport, the Boeing 367-80. Bill Boeing was 72 at the time and had long since divested his holdings in the company he founded, but he was present at the rollout of the the Dash 80 and Boeing's wife, Bertha, christened the aircraft with champagne while the Renton High School band played "Wild Blue Yonder", the USAF theme. I always thought this Boeing photo was cool- it's the Boeing president at the time, Bill Allen, showing the 367-80 to Bill Boeing. 

Allen bet the company on Dash 80, investing $16 million of the company's money to gear up for production tooling before having an order from either any airline or the US Air Force. 

But then again, taking a bold risk was something the company did three times undeniably in its history. The first time was in 1934. Boeing president Claire Egdtvedt proceeded with the Boeing 299 without any orders or contracts from the US Army Air Corps for a four engined bomber- the 299 is better known as the B-17 Flying Fortress. When Egdtvedt took his gamble on the 299 prototype, he asked his friend for guidance- who happened to be Bill Allen, who at the time was the company lawyer.

Almost twenty years later Bill Allen found himself in the same position when he launched what become both the KC-135 Stratotanker and the Boeing 707 with the Dash 80 prototype. 

And about 10 years later, Bill Allen was fishing in Puget Sound with Pan American chairman Juan Trippe when Trippe pressed Allen on building a jumbo-sized jetliner- legend has it that Trippe asked Allen "Would you build it if I buy it?" and Allen responded "Would you buy it if I build it?" and by the end of the day, the Boeing 747 was launched on a handshake. According to aviation author Robert Gandt, Allen thought to himself the 747 "would be the perfect swan song if he could step down knowing that he had launched the world’s mightiest ship of the sky. It would secure Boeing’s future well into the century. Or it could ruin Boeing".

Further reading: 

The XB-15: Getting Boeing Back On Its Feet

How a Tax Issue Launched the Boeing 707

The Development of the Boeing Flying Boom

The Boeing PBB Sea Ranger: The Best Flying Boat at the Worst Possible Time

Delta Air Lines and the Boeing 747-100

On 9 September 2015, the very first Boeing 747-400 built, N661US, touched down at Atlanta from Honolulu as Delta Flight 836 for the last time in revenue passenger service. Ship 6301 was the Boeing 747-400 prototype which was then delivered to launch customer Northwest Airlines on 8 December 1989 and came over to Delta with the 2008 merger. There are twelve remaining 747-400s flying with Delta, all of which came over from Northwest. Current fleet planning will have these 747s retired in 2017. Delta did however, for a brief time, operate the first variant of the 747 family, the 747-100, from September 1970 to April 1977. Only five aircraft were taken on strength with Delta and while the 747-100 was but a short historical footnote in Delta’s history, its legacy looms large to this day with the airline.

My own profile art of Delta’s first 747-100, N9896 “Ship 101” as it looked on her delivery in 1970.

(JP Santiago)

In order to understand what the 747 was for Delta at the time, one has to consider that as the 1960s were drawing to a close, Delta was in the midst of transition on several fronts. The first change change came with the Southern Transcontinental Route Case of 1961. Prior to deregulation, airlines often had to make a case for the opening of new services and routes to the Civil Aeronautics Board. Often these cases consisted of years of deliberation and often politics played a central role in airlines winning favorable rulings from the CAB. In the 1950s, the CAB favored interchange services as a means for airlines to open up new markets without saturating a given route with an excess of seats, harming profitability. Having a predominantly Southeastern US-anchored network, Delta linked up with several other airlines to offer interchange services which allowed it to fly as far west as California. As traffic grew on the interchange services to the West Coast, Delta petitioned the CAB to operate the West Coast services on its own and in one of the more historic decisions made by the CAB, both Delta and National were given route authorities to California from the southeast in what was called the Southern Transcontinental Route Case. Starting in 1961, the previous interchange agreements were declared redundant and Delta opened up a range of nonstop services to San Diego, Los Angeles, and San Francisco from Atlanta, Dallas, and New Orleans. Within a year, Las Vegas was added as well as Miami which for the first time made Delta a transcontinental airline. By 1963, the CAB permitted Delta to carry West Coast traffic to its Caribbean destinations via New Orleans and onward to Florida (Orlando and Miami) via Atlanta. In an unrelated decision by the CAB, Delta was allowed to interchange on routes to London from Washington Dulles with Pan American and soon Delta’s DC-8s were flying to Europe as part of that interchange agreement.

The second and biggest of these changes came with the death of Delta’s founder, C.E. Woolman, on 11 September 1968. In his 1841 essay “Self-Reliance”, Ralph Waldo Emerson wrote that “An institution is the lengthened shadow of one man...all history resolves itself very easily into the biography of a few stout and earnest persons." From Delta’s founding in 1927 to his death in 1968, no other individual was so closely identified with Delta than C.E. Woolman. He became the airline’s president and general manager in 1945 and became its chairman of the board only a year before his death. Though viewed as a stern autocrat by the press, Woolman was beloved by Delta employees. On his 25th anniversary with Delta, the employees presented him with a new Cadillac and though he had own several other cars, he kept that Cadillac until he died. Though ably succeeded C.H. “Charlie” Dolson, W.T. “Tom” Bebe and David Garrett, there was no question it was still Woolman’s airline for years to come.

The last change that frames the selection and operation of the Boeing 747-100 by Delta was its 1972 merger with Northeast Airlines. Throughout its history, adversity plagued Northeast which always seemed be hobbled by the CAB with a small network and when Northeast finally did break out of New England in 1968 with new routes to Florida, it ran square into the crosshairs of Eastern which was the incumbent giant of the US East Coast at the time. With Northeast literally going from cash crisis to cash crisis, its New England route authorities soon proved to be ripe for acquisition via merger. The first suitor was Northwest Airlines in 1969. Interestingly, the CAB approved the merger in 1970 but it would be without some of Northeast’s more attractive route authorities like Miami-Los Angeles. Northwest withdrew its merger offer in 1971 as a result. Eastern and TWA then offered merger terms, with Eastern in particular seeing a merger as a way of knocking a competitor out of the New England-Florida market. Those negotiations also fell through and ultimately it was Delta that came through with a suitable merger offer that also met with the approval of the CAB. On 19 May 1972, President Richard Nixon signed off on the Delta-Northeast merger (since foreign routes were involved).

So these are three events in which to put the context of the Delta’s order of the Boeing 747-100- the Southern Transcontinental Route Case of 1961, C.E. Woolman’s death in 1968, and the merger with Northeast Airlines in 1972.

Prior to the launch of the Boeing 747, the “big jet” of the day were the Douglas Super Sixty series DC-8s which had surpassed the Boeing 707 in utility and passenger capacity. While the 747’s launch has been historically associated with Juan Trippe and Pan Am, at the time, Boeing was keen on getting one up on Douglas and the 747 was the aircraft that would capture the “jumbo” jet title from the DC-8 Super 61/63. Delta representatives had visited Boeing to view the progress on the 747 program and were suitably impressed with the aircraft. Despite their favorable views on the 747 though, it was clear to all of Delta’s management from the outset that the 747 was too much airplane for the airline which had a predominantly short- and medium-haul route network with its longer routes suitably (not to mention cost-effectively) served by the DC-8 fleet. On the other hand, two of Delta’s biggest competitors, Northwest and American, had already placed orders for the 747. Delta’s fellow “southern transcontinental route” airline, National, was also expected to place orders for the 747 as well. The writing was on the wall- Delta’s DC-8s were no match for the expected spacious comfort of the big Boeing and the prudent move was to get the 747 as well, even if was just a small number on a temporary basis. In April 1967, Charlie Dolson, the airline president of the time, announced Delta’s order for three 747-100s for $20 million each with options for two more aircraft. It marked the very first time that Delta had ordered from Boeing. Preparations were made at six Delta destinations and three alternate cities for operation of the massive jet. When Pan American launched the world’s first 747 passenger services in January 1970, Delta had two representatives aboard the inaugural passenger flight.

Delta marketed the upper deck lounge of its 747s as the “Private Penthouse”.

(JP Santiago)

While Delta was making preparations for the arrival of the 747, it was carefully considering its future widebody needs which were better met by a smaller aircraft in the form of either the Douglas DC-10 or the Lockheed L-1011. Delta’s technical staff liked both aircraft and it was believed the DC-10 was favored given Delta’s long association with Douglas Aircraft and its extensive use of both the DC-8 and DC-9 in the 1960s. Delta’s close association with Douglas as one of its most loyal customers was the product of a friendship between C.E. Woolman and Donald Douglas. In the 1960s, Douglas encountered repeated financial and technical difficulties with both the DC-8 and DC-9 programs that resulted in financial losses that led to its merger with McDonnell Aircraft in 1967 which effectively put Donald Douglas out of the executive suite. And keep in mind it was the following year that C.E. Woolman passed away. In a sense, Delta was now a “free agent” no longer tied to Douglas. Lockheed, eager to put its reputation back on good standing after the issues with the Lockheed L-188 Electra, pulled out all the stops in the Tristar program, engaging potential airline customers aggressively and early on in the Tristar development, resulting in an aircraft that at least in Delta’s eyes, was practically custom-built for them. Delta did, however, order five DC-10 Series 10s as insurance against the Tristar program when Rolls Royce ran into serious financial trouble during the development of the RB.211 engine used on the Tristar.

Delta’s 747-100 order was fulfilled quickly with N9896 being handed over to Delta on 25 September 1970 with the aircraft arriving in Atlanta to great fanfare on 2 October 1970. N9897 was delivered on 25 October 1970 and N9898 was delivered on 18 November 1970. While Pan American was first to launch 747 services on 22 January 1970 on its New York JFK-London Heathrow route, mostly domestic 747 services were launched in quick succession that year:

25 February: Trans World Airlines, New York JFK-Los Angeles (first domestic 747 service)

2 March: American Airlines, New York JFK-Los Angeles

26 June: Continental Airlines, Chicago-Los Angeles-Honolulu

1 July: Northwest Airlines, Chicago-Seattle-Tokyo

23 July: United Airlines, New York JFK-San Francisco

25 October: National Airlines, Miami-New York, Miami-Los Angeles

25 October: Delta Airlines, Atlanta-Dallas-Los Angeles

21 December: Eastern Airlines, New York JFK-Miami

15 January 1971: Braniff International, Dallas Love Field-Honolulu

By the end of 1970, Delta put the other two 747-100s into service with flights to Chicago, Detroit, and Miami. The options for the two aircraft were exercised the following year with N9899 being delivered to Delta on 30 September 1971 and N9900 arriving on 11 November 1971. While Delta’s 747-100s flew amongst Atlanta, Dallas, Los Angeles, Chicago, Detroit and Miami, they were also put to use on the Pan Am interchange services between Washington Dulles and London Heathrow. In the space of just over ten years, Delta went from a mostly regional airline anchored in the southeastern United States with some Caribbean routes to a transcontinental airline operating the Boeing 747 with limited interchange services to London. Never before in Delta’s prior history had it grown so much. But its fleet was quite diverse as a result of the merger of Northeast Airlines- it had twelve different aircraft with eight different engine types in service- in August 1972, Delta had three variants of the Douglas DC-8 in service, three variants of the Douglas DC-9, two variants of the Boeing 727, the Boeing 747-100, the Convair CV-880, the Fairchild-Hiller FH-227, the Lockheed L-100 Hercules for its cargo division, and it was anticipating the arrival of both the Lockheed L-1011 Tristar and the Douglas DC-10! In the interests of reducing the maintenance costs, standardizing operations, and holding down spare parts inventories, the fleet types had to be pared down. By this point, David Garrett had become president of the airline and it was his legacy that Delta streamlined its fleet which gave it record breaking profits in the late 1970s. Garrett’s primary imperative was fuel savings- the 1973 OPEC oil embargo that followed the Yom Kippur War in the Middle East caused a sharp spike in the cost of fuel.

The Pratt & Whitney JT9D was the first production high bypass turbofan used on a production airliner.

(JP Santiago)

For smaller markets and the short- to medium-haul flying, Delta standardized on the Douglas DC-9 Series 32. For medium-sized markets and medium-haul flying, Delta standardized on the Boeing 727-200. It had acquired them via its merger with Northeast Airlines and found them to have superior economics to the Convair CV-880s and to some degree even the DC-8s. In addition, the 727-200 used similar Pratt & Whitney JT8D engines as the DC-9. There were thirteen 727-200s that came over with the merger with Northeast and Delta wanted more- in March 1972, Delta returned to Boeing once again, this time with an order for fourteen 727-200s (the order was placed before final approval of the Northeast merger by President Nixon)- Boeing even took Delta’s remaining Convairs as a trade-ins on the 727 order. By 1977, there would be 88 727-200s in Delta’s fleet. Delta’s first experience in working with Boeing on the 747-100 order was so favorable the airline was eager to work with Boeing quite readily again. The arrival of more 727-200s allowed Delta to dispose of the Convairs and the oldest DC-8s first. While most of the Series 51s and Super 61s were sold off, a sizeable number were kept on for several more years with some of the Super 61s getting the Cammacorp re-engining with the CFM56 to become Super 71s.

By this point it was clear the Lockheed L-1011 Tristar would be the long-haul workhorse of the Delta fleet. The DC-10s were eventually sold off to United. The first Tristar arrived in Atlanta on 12 October 1973 with the first passenger services on 15 December 1973 on the Atlanta-Philadelphia route. By 1974 there were ten Tristars in service but their spacious underfloor cargo holds meant they carried 25% of Delta’s cargo despite being less than 10% of the fleet. That allowed the L-100 Hercules transports to be sold off that year. When the Boeing 747-100 was ordered in 1967, it was with the understanding it was too big of an airplane for Delta but it was needed to compete in the marketplace. With the Tristar quickly proving itself, the 747-100’s days were quickly numbered and arrangements were made for the first two 747-100s to be sold off but the last three stayed on just a bit longer until more Tristars were in service. Delta’s last Boeing 747-100 service was flown 23 April 1977 Las Vegas-Atlanta.

Of the five original Delta 747-100s, only the first one, N9896 “Ship 101” can still be seen today at the Evergreen Aviation Museum.

(JP Santiago)

The fates of Delta’s five 747-100s:

N9896: Returned to Boeing 1974, leased to China Airlines 1976-1978, operated by Pan Am 1978-1991, then flew with Evergreen International. Preserved at the Evergreen Aviation Museum in 2010 (it’s on the roof as part of the waterpark with waterslides coming out of it!)

N9897: Returned to Boeing 1977, operated by Flying Tiger 1977-1989 (leased to El Al Israel for a year), operated by FedEx 1989-1991, operated by Air Hong Kong 1991-1996, then Polar Air Cargo, now scrapped.

N9898: Returned to Boeing 1975, operated by China Airlines 1975-1976, leased out by Guiness Peat Aviation 1976-1984, operated by Pan Am 1984-1991, operated by Evergreen International starting in 1991 and converted to a water bomber “Evergreen Supertanker”, retired with Evergreen’s bankruptcy in 2013. In storage at Pinal Air Park.

N9899: Returned to Boeing 1977, operated by Flying Tiger 1977-1989 (leased to El Al Israel for a year), operated by FedEx 1989-1991, operated by Air Hong Kong 1991-1995, then Polar Air Cargo, now scrapped.

N9900: Returned to Boeing 1977, operated by Flying Tiger 1977-1989, operated by FedEx 1989-1993, operated by Air Hong Kong 1993-1994, operated by Kalitta 1994-2008. Stored at Oscoda, then scrapped 2015.

As an interesting historical footnote, the first officer on the delivery of Delta’s first Lockheed Tristar was Captain Jack McMahan who at the time was one of only two men in the United States certificated to fly the DC-10, L-1011 and 747. The other pilot was an FAA examiner. He was asked by a reporter on his impressions of all three widebodies- he praised the handling of the DC-10, the overall design of the 747, and the advanced systems of the L-1011. He remarked “Flying the three planes is like going out with three sisters. They have the same background but different personalities!”

This article was originally posted on AirlineReporter.com on 23 October 2015.

Sources: Delta: The History of an Airline by W. David Lewis and Wesley Phillips Newton. University of Georgia Press, 1979, pp 340-392. Delta: An Airline and Its Aircraft by R.E.G. Davies. Palawdr Press, 1990, pp 76,80-86,96-97. 

The "Wings of Russia" Sukhoi Super Jumbo

The Sukhoi KR-860 was conventional in its layout

At the 2001 Paris Air Show, the Russian delegation created quite a stir by unveiling a four-engine, double-deck, long-haul airliner christened "Kryl'ya Rossii", or "Wings of Russia". The ambitious project had the Sukhoi OKB designation "KR-860"- KR for "Kryl'ya Rossii" and 860 indicating the passenger load. Design work on the KR-860 began in 1997 under the General Designer, Mikhail P. Simonov who had headed the design bureau since 1983. Already under his direction the Su-27 Flanker family of fighter aircraft had been upgraded and new variants had taken flight. By the time that design work began on the KR-860 project, Sukhoi had already been making its first steps into the civil aviation market with the start of work on the Su-80 utility transport and the Su-38 agricultural aircraft. But an aircraft in the class of the KR-860 was nothing short of a bold leap by Sukhoi. The "Wings of Russia" would rival the Airbus A380 and would be larger than the Boeing 747. The design team had looked at advanced technologies and unconventional layouts such as a flying wing, but eventually settled on a blend of advanced technologies (fly-by-wire, composites) combined with a conventional layout with a double deck fuselage and four turbofans. At each step of the KR-860's design evolution, tradeoffs were made between high technology and innovation and low-risk approaches. 

Note the twin nose gear and unusual cockpit fairing

Although the layout of the KR-860 was conventional in appearance, the Sukhoi team succeeded in achieving a predicted lift/drag ratio of 19.5 (compared to the L/D ratio of the Boeing 747 of 17) via aerodynamic refinements. Large winglets were a part of the design and the smooth lines of the double deck fuselage were unusually broken by a blister-like fairing that housed the flight deck. One of the more unusual features of the KR-860 was its use of folding outer wings to reduced the footprint of the aircraft. Boeing had looked at a similar system during the design of the Boeing 777 and had even built a test article, but eventually dropped the idea as the gain in space at the gate wasn't enough to offset the increased weight and complexity. For the KR-860, though, the folding outer wings meant that the aircraft could use any gate position that could accommodate a Boeing 747. While the main landing gear was very similar to that of the 747 and A380 with two inward-retracting wing units and two fuselage mounted units, the nose landing gear was more like that of the Antonov An-124 Condor transport with twin units. The third unique feature of the KR-860 was its three integral airstairs that were on the centerline of the underfuselage- the forward airstair was ahead of the nose gears, the second one was mid-way down the fuselage where the wings were located, and the third and aft unit was under the tail. Like the integral airstairs on the Ilyushin Il-86, these were meant to reduce the ground support needs for the KR-860. 

Note the folding outer wings and the boarding airstairs under the nose

A variety of powerplant options were evaluated for the aircraft- the most serious contender was the General Electric CF6-80E1 used on the Airbus A330 family of aircraft- Sukhoi was reportedly in negotiations with GE at the time of the KR-860's unveiling at the 2001 Paris Air Show. License production of the engine in Russia was even discussed. In addition, consideration was also given to the Rolls-Royce Trent 800 used on the Boeing 777 and the Pratt & Whitney PW4168 used on the A330. In addition, Russian solutions were evaluated from the Kuznetsov NK-93 ducted fan to the unusual suggestion of using eight Soloviev PS-90 turbofan engines in paired nacelles. This would have been the cheapest solution, but the pair nacelles and eight engines would have been significantly heavier and cost more in fuel consumption. 

The aft boarding airstairs under the tail

The eight-engined variant was considered more appropriate for a cargo variant which had an upward-hinged nose visor like that of the An-124 Condor and the Boeing 747-400F. Sukhoi even pitched this version as a successor to the An-124s operated by the Russian Air Force. The cargo version was capable of carrying up to thirty of the 40-foot rail/road cargo containers. Using four turbofan engines, such a version was claimed to have a cost per mile only slightly higher than that of rail transit. In addition, combi versions were suggested and one of the more unusual variants was that of a flying liquified natural gas (LNG) tanker to connect outlying regions in Siberia planned for oil/gas exploration that lacked suitable infrastructure for conventional transport methods. 

Sukhoi estimated the costs for the development of the KR-860 would be more than offset with its use in cargo transport. Costs depending upon the authority consulted ranged from 3-4 billion US dollars to as high as 5.5 billion US dollars. As ambitious as the KR-860 was, there was simply not enough passenger traffic in Russia to justify an aircraft its size. Sukhoi turned to both India and China which had booming passenger markets to explore risk-sharing partnerships. At the end of the day, though, an aerospace project the size and scope of the KR-860 was simply more than both Sukhoi and the Russian government could handle and with more pressing financial needs, the Kremlin was reluctant to invest in the development of Sukhoi's super jumbo. Russian aviation authorities were highly skeptical of the need for the KR-860 given that most of what might get built would be exported to more robust and booming aviation markets. As a result, the KR-860 "Wings of Russia" program died quietly as Sukhoi shifted its resources to a much smaller aircraft that was needed in Russia to replace the aging fleets of Tupolev Tu-134 and Tu-154 fleets. Though development of the Sukhoi SuperJet 100 had started in 1999, the shift of OKB resources from the KR-860 to the SuperJet program which was formally launched in 2002. 

Source: OKB Sukhoi: A History of the Design Bureau and its Aircraft by Yefim Gordon and Dmitriy Komissarov. Midland Publishing, 2010, p501-503.

The 747 Shuttle Carrier Aircraft (SCA)

The Boeing 747 was one of two choices for the SCA

During the design and development of the Shuttle Orbiter, air breathing jet engines were a part of the design for some time until cost and technical considerations in early 1974 led to their deletion from the concept. No longer able to "self-ferry", NASA now faced the problem of how to get the Orbiter from the remote landing sites to the launch locations. At the time NASA Langley had a study ongoing on a large aircraft design called VIRTUS that would have carried the Orbiter under the center wing flanked by twin fuselages and a twin boom tail with power coming from four Pratt & Whitney JT9D turbofans. Design work had proceeded on VIRTUS as far as wind tunnel tests with a 1/34 scale model, but sheer size, long development time and costs involved for an aircraft that would be built in very small numbers resulted in end of the VIRTUS project. At the time, Jack Conroy, the developer of the Super Guppy concept that NASA was using to transport rocket stages, had suggested using a jumbo-class aircraft to carry the Orbiter on its back. Proposals were issued to the industry and Lockheed offered up a twin-fuselage aircraft based on the C-5 Galaxy with the Orbiter suspended underneath a new center wing section- but, like the earlier VIRTUS program, it was eliminated from consideration due to cost, development time and that the design was so wide, no runway available could accommodate the design. Boeing offered a modified version of the 747 that carried the Orbiter on its back that presented a much lower risk approach. Boeing at the time even suggested that the large external tanks could be carried on the back of a 747, but wind tunnel studies showed the idea to be less practical than initially thought. Lockheed had subsequently reworked its design to a simple modification of a C-5 Galaxy to carry the Orbiter on its back much like Boeing's proposal. 

By mid-1974 Boeing's 747-based proposal and Lockheed's simpler C-5 Galaxy-based proposal were the only serious contenders to become the new Shuttle Carrier Aircraft (SCA). On 24 April 1974 NASA selected the C-5 Galaxy proposal from Lockheed based on it having the least acquisition expense and a C-5 Galaxy would need less structural modification than a Boeing 747. Accordingly, NASA approached the United States Air Force with the proposal and a request to make three to five C-5s available. The USAF was very receptive to the idea and the Lockheed proposal only added 400 to 600 pounds of modifications to the Galaxy without adversely affecting its cargo carrying capacity when not being used to transport the Orbiter. An arrangement was set up whereby NASA would pay for the modifications and then lease the modified C-5s as needed from the Military Airlift Command. One Galaxy was agreed to be bailed to NASA full-time for development into the SCA and for use in the atmospheric flight tests with the planned first Orbiter (which would become the Shuttle Enterprise). Despite some lingering concerns about the effects of the Orbiter's wake on the C-5's T-tail, both NASA and the USAF had worked out an acceptable arrangement for both parties.

N905NA conducted the atmospheric landing tests with Enterprise

The downturn in the American economy in the early 1970s led numerous US airlines to release their 747 aircraft which were too large for the market at the time. As a result, the acquisition cost of the Boeing 747 as the SCA dropped much lower than that of the Lockheed proposal. With the ready availability of low-time 747s on the market, NASA abandoned plans for using the Galaxy as it was decided it was much easier in the end to have complete control of the SCA than to have to compromise with military priorities for use of the C-5 Galaxy. On 18 July 1974 NASA purchased a used Boeing 747-123 (N9668, msn 20107) from American Airlines. It was the 86th 747 off the production line at Everett and was delivered to American on 29 October 1970. By the time of the NASA purchase, it had only logged 8,999 flight hours and 2,985 cycles flying primarily transcontinental services between New York JFK and LAX. NASA re-registered the aircraft as N905NA. Before modification into the SCA configuration, N905NA was used for in-house studies with NASA Ames on wake vortices. Following conclusion of the wake vortex research program, Boeing initiated the $30 million conversion program on N905NA on 2 August 1976. 

Not often seen is the sense of humor NASA has with the SCA

Boeing installed new bulkheads to strengthen the fuselage with skin reinforcement at critical stress areas. The horizontal stabilizer structure was also beefed up along with the addition of telemetry and transponder test equipment, fittings for the Orbiter support struts, and the installation of a 747-200 rudder actuator system. Boeing also developed a set of removable modifications for the SCA- the first one was a telescopic forward support assembly that was used only during the atmospheric flight tests with the Shuttle Enterprise. This support would hold the Enterprise at a six-degree angle of attack to facilitate release during the flight tests. A fixed assembly was also developed for use during SCA ferry missions that held the Orbiter at a three-degree angle of attack, which induced less drag during the ferry flights. The aft support assemblies (there were two) were common to both the atmospheric flight tests and ferry flights and finally 10 foot by 20 foot vertical endplates were added to the end of the horizontal stabilizer to provide additional stability when carrying the Orbiter- in practice, though, NASA never removed the endplates. 

The 747's trim system was also modified to allow a greater range of trim in pitch to counteract the downwash off the Orbiter's wing on to the horizontal stabilizer. Most of the main deck interior was stripped out, but some seats were retained for support personnel during the ferry flights. The JT9D engines were also converted to allow a thrust increase from 43,500 pounds to 46,950 pounds of thrust. The current JT9D engines on the current incarnation of the 747 SCA are rated at 50,000 pounds of thrust. Since each Orbiter has a different empty weight, an adjustable ballast system using standard cargo containers in the forward underfuselage cargo compartment had to be developed to maintain the center of gravity. On 14 January 1977 Boeing finished the modification work and after a period of flight testing, it was delivered to NASA. 

Concerns about flight crew safety during the atmospheric flight tests with the Shuttle Enterprise led NASA to incorporate an escape system on N905NA since the flight crew of the Enterprise had ejection seats. The escape system was based on what was used on the 747 prototype during Boeing's 1969 flight tests- in the event of an emergency, a handle was pulled that blew out thirty fuselage windows to facilitate rapid decompression of the aircraft. Three seconds later an emergency egress hatch on the lower forward fuselage was blown out with extendable spoiler being deployed. The crew would make their way back from the flight deck to the middle of the upper deck lounge area where a hole leading to a 16 foot escape slide would lead them out the blown hatch and clear of the aircraft. Testing showed the flight crew could bail out of the 747 within 11 seconds. The atmospheric flight tests will be the subject of a future blog post, so stay tuned. 

N905NA has three upper deck windows, N911NA has five

In 1988 NASA acquired a second 747 to act as a back up to N905NA. Part of this was driven by the recommendations following the Challenger accident that a significant portion of Shuttle flights would still be landing at Edwards AFB. The first 747-100SR was purchased from Japan Air Lines where it had flown as JA8117, msn 20781. Boeing purchased the aircraft from JAL on behalf of NASA and conducted the necessary modification work to bring it up to SCA standards with the new tail number N911NA. On 20 November 1990 it was delivered to NASA and in 1995-1996 both of the 747 SCAs were repainted in NASA's new colors. 

During a ferry mission the SCA' smaximum speed it 250 KIAS (Mach 0.6) at an altitude of 13,000-15,000 feet with a range of approximately 1,150 miles. Without the Orbiter, the SCA cruises at 24,000-26,000 feet with a range of 6,300 miles. During ferry flights the usual crew is two pilots and two flight engineers, but only one flight engineer is needed on non-ferry flights. At one point NASA looked at inflight refueling of the SCA as the equipment was readily available as it was installed on a handful of the USAF's 747s- the E-4 airborne command posts and the two VC-25A presidential transport aircraft. Proximity flight tests were even carried out with N905NA and a KC-135 tanker minus the Orbiter, but the discovery of cracks at the base of N905NA led to the termination of the studies as it was feared that wake turbulence from the tanker may have been possible. Plans were in motion to fly the proximity tests with an Orbiter, but the costs involved and wake turbulence concerns led to the quiet abandonment of the idea. 

Source: Space Shuttle: The History of the National Space Transportation System- The First 100 Missions by Dennis R. Jenkins. Specialty Press, 2001, p195-202.

Contrary to popular belief, QANTAS did not order its two Boeing 747SPs for the long distance Los Angeles to Sydney route. Rather, the airline's orignal plan was to use them to connect Sydney to New Zealand's capital, Wellington- located on the southern tip of the North Island of the New Zealand, Wellington had a short runway that made operations by regular 747s impossible. In addition, the airport was frequently affected by erratic winds and poor weather. QANTAS's original intent was to use the 747SP's ability to operate on shorter runways to serve Wellington with more profitable payloads despite the operational limits placed by the airport authorities for safety reasons.

The first QANTAS 747SP entered service on 6 February 1981 as QANTAS Flight 55 Sydney to Wellington, but had to divert to Auckland due to poor weather at Wellington.

Only QANTAS captains were allowed to land the 747SP at Wellington as the first officer monitored the approach which was conducted at 125 knots to insure that the landing could be made using the markers painted on the runway. Landing too fast, too high, or too long, was a mandatory go-around.

It wasn't until 1984 that the airline's 747SPs were used on the Sydney to Los Angeles route.

Source: Airways, November 2008. "QANTAS Double Trouble!" by Mac af Uhr, p51.