Returned To Service

By Joe Thompson
13 June 2008

Part One: From Cradle to Grave...Almost!

The Genius Of An Aircraft

The saga of the Lockheed L-1011 "TriStar" actually started in the 1960's when American Airlines indicated to Lockheed and Douglas that it was in the market for a wide-bodied airframe that was smaller than the B-747 but still had a large seat capacity and sufficient range to fly to Europe or South America from hubs in New York and Dallas. Up until this period Lockheed had been absent from the commercial aircraft market; following the massive problems they encountered with their L-188 Electra. Lockheed initially envisioned a very large twin engined aircraft as their response to the design challenge but eventually added a third engine to increase takeoff performance from shorter runways. Their solution for the third engine though would be far different than what Douglas chose for their entry into this competition, the DC-10. (The DC-10 was McDonnell Douglas's first commercial airliner after the 1967 merger between McDonnell Aircraft Corporation and Douglas Aircraft Company). McDonnell Douglas eventually used two different engines types for their aircraft, the Dash 10's and Dash 30's used General Electric CF6 whereas the Dash 20 (later re-designated Dash 40) which was only bought by NWA and JAL used the Pratt & Whitney JT9D powerplants. Lockheed on the other hand elected to go with Rolls Royce engines for all models of their TriStar.

The Lockheed design, unlike the high, tail mounted engines found on the DC-10, installed the number two engine within the rear section of the fuselage. This engine would receive its air through a curved "S" duct that ran beneath the vertical fin. The B727 uses the same design. However at the outset, Lockheed's engineers knew they needed a shorter engine in terms of overall length to fit inside the tail. Rolls-Royce had one under development that fit this parameter. Initially Lockheed was excited to team with Rolls-Royce on the TriStar project. Rolls-Royce was working on a "three-spool" engine designed that promised much greater engine efficiency than was offered by other jet engines. In the three-spool design three turbines spin separate shafts to power three sections of the compressor area running at different speeds. In addition to allowing each stage of the compressor to run at the correct speed, the three spool design is also more compact and rigid, although more complex to build and maintain. And having one more shaft than usual, the engine rotation speed is reduced resulting in less noise. The RB211 engines have a by-pass ratio of 5:1, driving some 70 percent of the thrust around the outside of the core. In fact the TriStar still complies with Stage III regulations without any engine modification required.

Unfortunately during this period Lockheed found itself in serious financial difficulties exacerbated by the C-5A Galaxy contract and the cancellation of the Army's Cheyenne helicopter. Then Rolls-Royce announced serious difficulties with the development of the RB211 engine. Rolls had elected to use Hyfil, a proprietary carbon-reinforced epoxy that resembles plastics used in today's tennis rackets, on the front fans of the engines. This would save 900 pounds of weight but these hi-tec blades proved to have severe problems during bird strikes. Rolls swapped them out with titanium blades but this in turn added more weight to the engines and was a major setback for the RB211 project. The overall development time line for these new engines had also been underestimated as had their development costs. This lead to the financial collapse of Rolls-Royce in February 1971 and only after the British government stepped in and assumed control. The continued development of the engine though required that Lockheed pay a much higher price to cover the real costs of that development. Lockheed knew that at this juncture to replace the RB211 with either the Pratt & Whitney JT-9D turbofan or the General Electric CF-6 would cost a year in time and $100 million in development costs. Neither of the GE or P&W engines would fit into the current TriStar fuselage housing assembly without a major redesign which in turn meant additional wind tunnel testing and other laborious testing to gain FAA certification. Lockheed was caught between the proverbial 'rock and a hard place' and opted to stick with the Rolls engine.

The first L-1011 took to the skies over Lockheed's Palmdale, California plant on 11 Nov 1970. Between then and 1980 they produced 250 TriStar's (163: model 1, 13: model 100, 24: model 200, and 50: model 500). The name by the way is in keeping with the Lockheed tradition of naming their passenger aircraft after celestial bodies; e.g. Constellation, Orion, and TriStar. Unfortunately in the end several factors proved to be obstacles that were too much to overcome for Lockheed and its TriStar. First was the disastrous debacle involving the engines; even though the RB211's eventually proved to be outstanding powerplants, the delay meant that the DC-10 had been in production over a year before the first L-1011 rolled off the Palmdale line. On top of this was Lockheed's tardiness in providing a longer ranged aircraft. Lockheed didn't fly the first short fuselage L-1011-500 until early 1979 and then it was too late. McDonnell Douglas had a deep seated customer base, proven support infrastructure for their aircraft and Lockheed was unable to make up the ground they had lost

Lockheed initially estimated they needed to produce 300 aircraft to break, but that figure actually proved to be about 500 - they only built 250. In the end Lockheed lost $2.5 billion on the TriStar project and the experience buried them in commercial aerospace. In December 1981, Lockheed announced they were stopping production. In the end the Tristar, which was Lockheed's 'reintroduction' into the commercial airliner marketplace, proved to be Lockheed's last commercial airliner venture.

The DC-10 never broke even either even though 386 were sold to the airlines and an additional 60 to the Air Force as tankers (KC-10 Extender). The fierce competition with the Tristar's and a troublesome safety record proved a nemesis that the Douglas plane could never quite shake free of.

With all the turmoil surrounding the TriStar and even though Lockheed eventually lost out to McDonnell Douglas the L-1011 was considered to be technically far more advanced than the DC-10 by its crews, owners, and aviation experts. Some of the high tech and/or innovative features found on the L-1011 were such things as:

• Noise - The RB211 engines were so quiet the aircraft was dubbed 'The Whisperliner' by Eastern Airlines. The moniker stuck throughout the industry. The cabin was also much quieter than other aircraft of similar size because the engine nacelles were hung farther out on the wings than was the norm. What permitted the positioning of the wing mounted engines farther outboard was the use of the "S" ducted center engine. Since this engine was lower in the tail than mounted on the tail it allowed for a larger and more effective rudder.
• Additional Hydraulic Systems - Four independent hydraulic system lines for more redundancy to power the control surfaces such as ailerons, elevators, rudder, slats/flaps, etc. The DC-10 has only three hydraulic systems. The L-1011 was also the first aircraft to incorporate a Ram Air Turbine (RAT). The RAT, a small turbine with a small propeller that deploys below the fuselage when required, is connected to a hydraulic pump or electrical generator and is used as an emergency power source. In case of the loss of both primary and auxiliary power sources the RAT will power vital systems (flight controls, linked hydraulics and also flight-critical instruments).
• Digital autopilot - The L-1011-500 was the first wide-body commercial aircraft to have a digital auto-pilot instead of an analog system. One of the most accurate auto-pilots ever built its high degree of accuracy when used in conjunction with the also technologically innovative Direct Lift Control system permitted the L-1011 to easily attained CAT III capability.
• Direct Lift Control (DLC) - The DLC is a system particular to the L-1011 which was designed to control inboard spoilers' deflection during final approaches to provide vertical speed control without significant changes in pitch attitude. The DLC operation results in a smooth and constant pitch attitude approach and also works automatically with the autopilot. This concept is similar to the principle of using spoilers on a glider in the final approach, thereby controlling the rate of descent without changing the glider's speed. When flaps were selected into the Landing range, the spoilers popped up to a null point (on the early models) of 7 degrees. Thereafter when pitch inputs were made, the spoilers would deploy further - up to 14 degrees for pitch down inputs and down to zero for pitch up inputs. The null position was increased on the Dash 500 to 9 degrees. Interesting to note that "another aircraft" that uses DLC is the Space Shuttle.
• Active Control System (ACS) - While Douglas was studying and testing winglets in its DC-10 aircraft - which were eventually introduced in the MD-11 - Lockheed believed that a more efficient way of reducing induced drag for better fuel economy was by increasing TriStar's wingspan giving a higher aspect ratio to the wing. However, increasing the wingspan usually requires wing reinforcement and thus higher aircraft weight. The solution found was to design an active system which works for wing load alleviation.. Accelerometers installed in the fuselage and wingtips of the L-1011, detect vertical accelerations induced by turbulence or maneuvers and automatically deflect ailerons to redistribute excessive wing load. This is accomplished by deflecting the outboard ailerons in the same direction simultaneously to redistribute wing loads inboard. This reduces wing vibration and wing tip and wing root bending loads during maneuvers and in turbulence.
• Performance Management System - This is another system particular to the L-1011 which is incorporated in the Flight Management System. Lockheed noticed that optimum cruise Mach number was unstable to keep resulting in lots of throttle movements and corrections. In other aircraft, many airlines would opt for a higher Mach number which also led to higher fuel burn. The PMS was designed to keep airspeed precisely by changing, with small variations, the aircraft's attitude. If the airspeed is above the selected figure, a nose-up command is sent to the horizontal stabilizer making the aircraft rise a maximum of 50 feet and lose speed; conversely, if the airspeed falls below the selected figure, a nose-down command is sent and the L-1011 sinks a maximum of 50 feet to gain speed without throttle correction. The benefits from this system were better fuel efficiency, extended engine life and less auditory fatigue for the passengers due to thrust variations.
• Air conditioning - TriStar's air conditioning system totally renews air in the cabin every 3 minutes, resulting in a much more enjoyable atmosphere. The majority of other commercial aircraft, even the ones today, use re-circulated air sacrificing passengers' comfort for fuel efficiency purposes.
• Door operation & configuration - The L-1011 doors slide up into the fuselage whether in electrical, emergency or manual mode. This designed ensured that, in case of emergency, no outside obstacles could prevent the doors from being opened. The forward loading doors were double width and there were no doors over the wings, this allowed faster emergency exiting from these doors via an escape slide.
• Four anti-collision lights - The majority of commercial aircraft flying only have two anti-collision lights (the red rotating/blinking lights), one on top and the other on the bottom of the fuselage. For redundancy purposes, the L-1011 has two on the top and two under the belly. If one failed, the aircraft could still be dispatched without delaying the flight.

L-1011 Model Limitations / Differences

* Rounded off.
** The exterior difference between a Dash 500 and previous models is the shorter fuselage, and on most but not all -500 model you will find three doors per side vice four doors. The forward cargo door on the -500 is also larger. In the interior the most oblivious difference, other than less seats of course, is that the -500 eliminated the below deck galley arrangement and its accompanying service elevators and placed the galley on the main deck.
*** Allowable X-Wind components for Autoland and to initiate a CAT II/III Approach are not shown. These would be less than what is displayed.

Graveyards and Boneyards

Some evidence seems to support a long held legend that there are places deep in the African bush where old elephants instinctively go to die. They sense their time has come to an end in this world and through some deeply ingrained animal instinct they travel to this special place to die. Legend also has it that these places, referred to as elephant graveyards or boneyards, are strewn with the bones of thousands of once majestic animals.

Airplanes have their own 'boneyards' too. When airline managers decide that, for reasons of corporate efficiency, newer technology, or cost-benefit analysis, that a particular aircraft or an entire fleet of airplanes are no longer the proper mix for the airline then they are transfer to one of these aircraft storage facilities to wait their eventual fate. Places with names like Mojave, Davis-Monthan, Pinal Airpark, Tucson, Gray Bull, Kingman, Roswell, and Victorville serve as the finally resting place and the site of the eventual destruction of many a great airplane.

Some aircraft succumb to spectacular and often tragic ends resulting from a crash. Their paperwork is noted WU - "Written Off" and the final chapter is closed on their existence. Most aircraft however, meet a far less spectacular end. After years of service most commercial aircraft eventually find their way to a storage facility normally in the desert southwest of the Unites States. Some are placed in storage for a period of time until their owners decide that it is merely more expedient to scrap the aircraft after its salvageable parts are removed. The aircraft sit in the heat and dust and as their once magnificent paint schemes fade from view, in a nearby building their records carry notations such as WFU - "Withdrawn From Use" and STD - "Stored." The eventual final fate for most is to be parted out; all salvageable parts are removed and then the aircraft is chopped up and sold to a scrap metal dealer. Records for aircraft relegated to this fate are then marked - BU - "Broken Up." Occasionally however an aircraft receives a reprieve from the chopping block and following its sale or lease she is refurbished and placed back in service. These aircraft have their files marked RTS - "Returned to Service."

And as is the procedure for most stored aircraft we can envision her arriving in Victorville to little pomp and ceremony. The last aircraft of a fleet type when retired to a desert storage area is normally sent off from its last hub airport with much fanfare and is even greeted at the "boneyard' with some special events to bid them goodbye. But those that follow before are privy to none of that. They merely show up, the paperwork is passed from airline to the caretakers, the ferry crew leaves for a local airport to fly home and the aircraft begins a less than glamorous existence. These desert locales, many of which are several thousand feet above sea level provide a low humidity environment that is conducive to the overall maintenance of the aircraft. Costs are relatively low also with an aircraft owner paying upwards of $10,000 USD for the initial preparatory work for storage on a large airliner and then several hundred USD's a month in storage fees. The owners stipulate the inspection cycle to be maintained on the aircraft and inspections cover such things as boost pumps, landing gear and tires, external fuselage surfaces, hydraulic lines, auxiliary power units (APU) and the engines. Naturally most openings such as doors, windows, static vent, overboard posts, engine intakes etc are thoroughly sealed to protect them from the elements - and desert vermin.

Delta and the TriStar

All stories need a central character. Naturally for this one it's a TriStar, but which one? I could have merely fabricated one and taken it from there but I felt it would be more meaningful if I grounded the foundation of the story in reality. Therefore I selected a Delta L-1011 in desert storage to serve as the centerpiece for this story. The aircraft, N761DA, actually exists. Its history up to the point of being Returned to Service is factual. All events thereafter in this story are fictitious.

The first Delta L-1011, N701DA (msn 1041) rolled off the assembly line in Palmdale on September 7, 1973. It was delivered on October 3, 1973. As happens with all airliner fleets eventually the aging aircraft were replaced; Delta TriStar's were replaced on the Atlantic Oceanic routes by B767's, and by MD-11's in the Pacific. Delta's last L-1011 in fleet service, N728DA a Dash 500, was ferried to Victorville for storage on 01 August 2001.

Our story aircraft, an L-1011-500, first flew on 01 April 1981 and carried the manufacturers' serial number 193Y-1208. The 193Y was the production code for Pan American World Airways and the 1208 indicated that this was the 208th L-1011 that had been produced. Pan Am took delivery of the aircraft on 27 May 1981 and registered her as N513PA, naming her 'Clipper Wild Duck'. Pan Am flew this aircraft until 1988 then sold her to United Airlines. United took possession on 10 February 1986, retained the old Pan Am registration, and flew the aircraft for two years before selling her to Delta Airlines in 1988. Delta took possession on the 19th of May 1988 and reregistered the aircraft as N761DA. She flew with Delta until her retirement in 1999.

Some Delta TriStar's ended up at Mojave Airport in California but the vast majority of them were retired to the Southern California Logistics Airport (VCV / KVCV) in Victorville, California. It lies approximately 40 miles NE of Los Angles and is, ironically, only 35 miles east of Palmdale, California where all the L-1011's were produced. Commonly referred to simply as 'Victorville,' the airport was once George Air Force Base until its closure in 1992. To soften the economic impact of the closure on the surrounding civilian community the airport was envisioned as a global intermodal logistics hub for the western US. Even with many business inducements, runway expansion and declaring the airport a Foreign Trade Zone, the vision never came to fruition. Instead Victorville became the final resting ground for many airliners as they served out their usefulness with carriers around the world. In a twist of irony the only wide-bodied aerial fire tanker, a converted DC-10, 'Tanker 910', is operated by the California Department of Forestry (CALFIRE) and uses VCV as its home base and returns here for reloading on all fire suppression missions within California.

A New Lease on Life

And now after more than a half dozen years sitting in the hot desert sun N761DA looked like a beached whale carcass. The familiar Delta Airlines livery paint scheme was faded and most of the rudder paint had been removed. The large "DELTA" fuselage logos along with the Delta "widgets" near the forward doors had been painted over. She looked neglected; she also looked as if she longed to be flying again. It was at this juncture that SkyLIFT International, doing business as (dba) "skyLIFT" decided to purchase an L-1011-500 and place her in service out of Honolulu, Hawaii. The intent was to fly the aircraft on weekly service from Hawaii to Las Vegas. This would be a gamblers junket that would depart Honolulu on Thursdays, make stops in Kahului, Maui, and Hilo, Hawaii and then fly on to Las Vegas. The aircraft would sit on the ground through the weekend and then return to the islands on Sunday. She would also be available for specialized charters, primarily throughout the Pacific area. Once skyLIFT executives located an appropriate airframe and after the purchase, the aircraft was moved from its normal storage location off the approach end to Victorville's runway 17 down to the main ramp for refurbishment. The process to bring a large aircraft like ours back into airworthiness compliance is long, arduous, and involved lots of work hours and quite a bit of money. Naturally revitalizing the engines and finding parts for the Rolls-Royce RB-211 is critical and not an easy task in today's aviation world. But after a lot of hard work and some major scrounging around for parts our aircraft was ready to fly. Now she was reregistered as N513SL, as she sat on the tarmac ready to start her journey back to that coveted status - Returned to Service. She still bore the weathered Delta Airlines paint scheme but skyLIFT company decals were applied to the main fuselage as were the new "N" numbers and she was ready to ferry.

SkyLIFT officials had selected an aircraft paint company doing business out of Roswell, New Mexico to repaint the aircraft, so the first thing on the agenda was to get the aircraft the 650+ miles down to Roswell. So on an hazy, humid morning our skyLIFT TriStar crew of three, all with previous Ten Eleven experience, signed the final paperwork and were off for New Mexico. The aircraft had been test flown for hours in and around Victorville working out various bugs in the refurbished systems but this was the real deal now. At the departure end to runway 17 the Victorville tower controller pushed his mike button and said," One Three Sierra Lima, wind two four zero at eight gusting to fourteen, cleared for takeoff, left turn after departure approved. Have a nice flight, gentlemen." After getting the gear up and the flaps and slats in on schedule the TriStar banked to the left and pointed her nose to the east and her first navigation aid - the Hector VOR. This carried the aircraft east over the Mojave Desert and after Hector over flew Needles, California on the west back of the Colorado River that separates Nevada and California. From Needles the TriStar angled off to the east south east and flew to Prescott and then over the eastern expanses of Arizona into New Mexico. From Truth or Consequences ("Tee-R-See" as the locales fondly call it) on the banks of the Rio Grande River and the huge Elephant Butte Reservoir the TriStar took up a more easterly heading that carried her over the heart of the White Sands Missile Range and into Roswell (ROW / KROW).

Roswell Industrial Air Center, like Victorville, use to be something else. During World War II the field was known as the Roswell Army Airfield. After the war it was Walker Air Force Base and served as a Strategic Air Command base until its closure in 1967. Today several non aviation related businesses occupy facilities on and near the airport property but the largest visible tenants are the dozens of old airliners that are stored and or refurbished at the airport. Airframes like B747's, DC-8's, L-1011's, MD-80's and 90's and DC-9's sit silently baking in the hot New Mexico sun. You can see their fuselages festooned with names like, Polar Air Cargo, American, Delta, ATA, UPS, BAX, Arrow Air, Continental and TWA. On the ramp near where the TriStar would park, amidst all these old airliner relics, sat several brand new Boeing 757's in bare metal waiting to be painted before joining their airlines in revenue service. 'One Three Sierra Lima' rolled to a stopped as the ramp worker crossed his paddles. Several people had gathered outside their office spaces to watch the new arrival. Engines were secured, chocks set and the large TriStar came to rest after her 1 hour and 53 minute transit from Victorville. She would sit here for two weeks being prepped and painted before leaving for Honolulu and her second lease on life.

In Part 2 climb in the jumpseat of the newly painted TriStar and fly with her to Hawaii.

As always I invite any and all comments regarding the story.

Joe Thompson
joe308@zianet.com

Flightsim Model Note: Though the story features a short-bodied L-1011-500 model the author used a Dash 100 model to "fly" the story. The L-1011 used in the story is an offering by Erick Cantu on his Vistaliners web site. And even though this model is only a beta version, in the opinion of the author, it is the best quality TriStar model currently offered for flight simulation. The author did however modify the aircraft.cfg parameters to more closely replicate a Dash 500 TriStar.