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Best of Airways: NASA DC-8 The Flying Laboratory

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Best of Airways: NASA DC-8 The Flying Laboratory

Suresh Atapattu

Best of Airways: NASA DC-8 The Flying Laboratory
March 22
14:46 2018

Written by Chris Sloan. Photos by Suresh Atapattu • Airways Magazine, October 2017


In May 1969, mankind hadn’t even set foot on the moon for the first time, but a Douglas DC-8 Series 62 was already plying the skies for its first owner, Alitalia (AZ) (Airways, November 2015).

Nearly 50 years later, this rare first generation jetliner (I-DIWK • MSN 46082) is still earning its keep up in the stratosphere. While nearly all of its jet contemporaries have long since been retired and consigned to scrap, this unique DC-8 flies on for a different owner on a mission radically different from the one its creators imagined. It is now NASA’s Armstrong Flying Laboratory.

Chasing History


I am not old by any means, but I am sufficiently advanced in years to have experienced the ear-bleeding, smoke-belching majesty of first generation jetliners like the Boeing 707, the Convair 880/990 (Airways, May, June 2017), the de Havilland Comet, the Vickers VC10, or of course, the DC-8 (Airways, January, February 2016).

All of them had vanished from front-line passenger missions by the early 1980s. Three DC-8s are still used as freighters and less than 10 are flying in special configurations, such as NASA’s.

Some Boeing 707s, and their military variants, remain in use by the United States Air Force—as KC-135s—a few government users, and two by Omega Air Refueling Services. Even early wide-body jetliners such as the Lockheed L1011, the McDonnell Douglas DC-10, and the early Boeing 747 variants have long since passed from the scheduled passenger flying scene.

I had the fortune of flying the last revenue passenger flight of a McDonnell Douglas DC-10, and a mission on NASA’s Boeing 747SP SOFIA (Airways, January 2017). But rides on the elusive DC-8 and 707 were shaping up to be a no-show in my AvGeek bucket list. John Travolta retired his 707, and I don’t know any members of the Royal Family of Congo, so my chances of flying onboard a 707 are slim to none.

There remained one trophy to catch for my mantle: NASA’s DC-8-72, now registered as N817NA.

This special machine began its life as the 458th Douglas DC-8 off the production line in Long Beach. Debuting in 1967, the Pratt & Whitney JT3D-powered DC-8-62 was the longest-range aircraft of its day. It could carry up to 189 passengers and fly 5,200 nautical miles with a full payload.

Alitalia took delivery of this particular DC-8 in May 1969, and christened it as Giacomo Puccini after the famous Italian opera composer. After about a decade of service with Alitalia, Giacomo Puccini was sold to Braniff International (BN) in January 1979, and re-registered as N801BN. Braniff operated DC-8-62s as the backbone of its extensive Latin American operation based out of Miami (MIA). This DC-8’s tenure with Braniff would last just 3½ years until the carrier’s demise on May 12, 1982.

New Chapter. Old Plane


The current chapter in the life of this DC-8 started in earnest in September 1984 when it was purchased by Miami-based Quiet Nacelle Corporation, where it was converted to a DC-8-72 after receiving four high bypass turbofan CFM56-2 engines in February 1986.

The CFM-56 engine is capable of producing up to 24,000lbs of thrust with a 6:1 bypass ratio.

These new engines provided increased power, at 22,000lb of thrust, improved fuel burn, and were quieter as well.

NASA purchased the airframe in 1985, re-registered it as N717NA, and started initial flight tests in 1987 at NASA’s Ames Research Center. The aircraft’s first mission was flown in 1989, nearly a quarter of a century ago.

At 157ft long with a 148ft wingspan and a range of 5,400nm, the aircraft could fly at altitudes of around 42,000ft for up to 12 hours, carry 30,000lb of scientific instruments and equipment, and seat up to 45 experimenters and flight crew.

Currently based at the NASA Armstrong Flight Research Center in Palmdale, California, it has proved ideal for supporting the agency’s Airborne Science mission. Federal, state, academic, and foreign scientific investigators are among the users of this aircraft.

A Myriad of DC-8 Missions


This DC-8 serves a multi-purpose role, gathering data, as NASA says, “for studies in archaeology, ecology, geography, hydrology, meteorology, oceanography, volcanology, atmospheric chemistry, cryospheric science, soil science, and biology.”

The jet flies four types of missions: sensor development; satellite sensor verification; space vehicle launch or re-entry telemetry data retrieval and optical tracking; and basic research studies of the Earth’s surface and atmosphere.

Its sensors and data systems can be tailored to execute specific missions or carry customized instrument sets. NASA’s DC-8 has Iridium and Inmarsat satellite communications capabilities: one for flight crew communications and one for science team communications, a multichannel system for the upload of meteorological data, chat messaging, limited data telemetry, and live Web page updates.

The AIMMS-20 probe (right, aircraft instrument) and the MTHP (Microwave Temperature Humidity Profiler from NASA JPL) probe (left)

Captain Corey Bartholomew says that it is an ideal platform for its missions, even compared to more modern aircraft. “It has a very robust structure for modification,” he says.

“We can uniquely put holes in the airplane facing up and down, probes in place of windows, and place large antennas on it. It is very suitable for a variety of modifications. Its four engines allow us to fly beyond ETOPS rules on up-to 12-hour mission with redundancies in systems.”

The plane’s biggest advocate may be NASA Mission Director Chris Jennison, who, as the most senior, has been with the program for 23 years. He manages the flight and acts as an intermediary between the science team, instrument operators. and the flight crew.

The mandate is to keep the cockpit as sterile as possible. Communication and direction between the Pilots and science must go through the Mission Director.

Due to its robust construction, “the DC-8 has waived aging aircraft requirements,” Jennison says. “It is a slide-rule designed airplane. The skin is thick at .050 inches”. Douglas designed an airplane as strong as anything built today.”

Flight Engineer Mark Crane, another long-timer on the program who also flies the third seat on the Hercules C-130, praises the redundancy on the DC-8: “You can lose two motors, numerous electrical and hydraulic systems, and be safe. That said, we’ve never had an engine flame-out during flight.”

Adds Jennison: “The CFM-56 engines are still relatively good for fuel efficiency, meet Stage III ICAO noise abatement standards, and four engines provide an additional measure of security.”

The DC-8 lines up on the centerline of FLL’s Runway 10L as its four engines spool up. All three crew members are completely focused on the task.

Old But New


Although the aircraft is clearly old, the crew doesn’t consider it obsolete in the slightest. It is not a relic; it is reliable.

“Dispatch is quite good at 90%,” says Jennison. “The aircraft is looked after by a dedicated maintenance team, with Boeing contracted to do the heavy checks. The squawks are mainly older electrics and 1960s technology electro-mechanical relays. To remain current, we’ve upgraded avionics, gyros, and air data computers.”

Because NASA doesn’t have to apply to the FAA for certification, it can install its own systems and solutions at will. A glass avionics suite is slated for the flight deck in the next few years.

Relatively speaking, N717NA is a young frame. As of our mission of June 10, 2017, the airframe had logged 54,148 hours and 18,886 cycles. It had flown 655 missions with NASA over 28 years, averaging 500 hours of flying per year. The aircraft could easily be flying into the middle of the next decade, with no replacement on the horizon.

The NASA DC-8 reaches its V2 speed and begins its storm-chasing mission.

NASA has five Pilots assigned to the Convective Process Experiment (CPEX) campaign with a total of 10 qualified to fly the DC-8. And how does NASA find qualified Pilots to fly such a rare platform? They train and stay current on the last DC-8 simulator in the United States. The Level B simulator is run by ABX in Wilmington, Ohio—a cargo airline that was among the last to fly the DC-8.

The Pilots don’t count on the sim to train for landings—that happens in the real world on the airplane. As with SOFIA, the Pilots are qualified on other aircraft in NASA’s possession, such as the Falcon 20 and Gulfstream III.

Current Mission: Chasing Storms


Throughout its lifetime, N717NA has been deployed in support of research in Australia, Bermuda, France, Germany, Austria, Italy, South America, and Africa. June 2017 found the aircraft based in Fort Lauderdale (FLL)—fortunately just a few miles from the Airways headquarters—for the CPEX Campaign.

Over that month, the Flying Laboratory conducted 16 missions for 93.2 flight hours. While most flights avoid convective weather, CPEX sorties directly confront it.

The June mission coincided with the beginning of South Florida’s rainy season, and Fort Lauderdale was easily accessible to storms in the Western Atlantic Ocean, the Caribbean or the Gulf of Mexico.

CPEX’s goal is to improve the accuracy of forecasting of the location and precipitation potential of these unpredictable, seemingly random, compact, and often short-lived storms. “We want to know what’s the difference between scattered convection that are scattered storms versus those that organize into larger organized systems,” said CPEX Program Co-Leader Ed Zipser, a professor of atmospheric science at the University of Utah.

“We want to learn about the wind surrounding convective storms,” added Co-Leader Shuyi Chen, a project scientist with the University of Miami. “How does the wind create storms? We want to be able to predict these storms more accurately over the ocean. Conditions are very different over water than over land. This can also help us understand how to improve Hurricane models.” Zipser elaborated. “We want to understand how deep convection takes heat and moisture in the low levels and brings them to the upper part of the troposphere,” he said. “Every raindrop releases energy. This drives weather and climate. When warm, moist air rises, it releases heat. Sun heats the ocean or tropical continent. This is the most important part of the air and water cycle of the atmosphere.”

The DC-8’s cabin is a mix of 1960s vintage and 21st Century high tech. Up front, workstations are commanded by the Mission Director and Assistant Mission Director, followed by airline-style seats with other passengers.

By flying near and into weather, CPEX records the genesis, growth, and demise of these storms, penetrating deep moisture normally out of reach of conventional flights.

“We’ve known since the 1970s that the key to a successful forecast is being able to understand and treat the role of convection,” Zipser said. “We’ve made a lot of progress, but none of the model treatments of convection is anything you could call perfect. We need to observe better and understand more. CPEX is a pretty exciting opportunity to learn more about convection and its evolution.”

Depending on the mission, the DC-8 Flying Laboratory is fitted with numerous instruments and, in this year’s CPEX sorties, a suite of five NASA instruments was flying together simultaneously for the first time. These included a DAWN (Doppler Aerosol Wind Lidar), an APR-2 (Airborne Second-Generation Precipitation Radar), and three microwave radiometers developed by JPL (the Jet Propulsion Laboratory) that measure ‘the holy trinity of convection’: water vapor, temperature, and the amount of liquid in clouds.

Mission Flight 1194


Our full mission briefing began at 09:00 sharp. Just like my trip on SOFIA, I was given a life hack tip: bring along some treats for the crew.

The CPEX mission’s flight paths are determined by weather forecast models constructed by 15:00 the previous day. These enable the identification of two target box areas in which convective chances are predicted to be the highest. This flight plan is scrutinized, refined, and then finalized on the day of the flight.

In our pre-flight briefing, Captains Greg Slover and Cory Bartholomew reported thunderstorms in the vicinity of Fort Lauderdale. Although thunderstorms are optimal during the in-flight science part of the mission, they can delay takeoffs. Delays can hinder scientific gathering or, in the worst cases, cause flights to be cancelled.

The flight plan set out a six hour 30 minute mission to investigate two areas of interest. The DC-8’s takeoff weight would be 270,000lb, with 100,000lb of fuel loaded. V1 was set for 129kt, Vr at 133kt, and takeoff flaps at 23 degrees.

The workstation of the Navigator.is one of the busiest locations onboard the DC-8.

Once airborne, the flying time called for 90 minutes to reach the first area of interest and 50 minutes for the first mission at FL300. This would be followed by a 30-minute transit to the next box and the next 50-minute mission.

Indicated airspeed would be set generally below 340kt for instrument effectiveness. Requests were made for right turns around the boxes. Dropsonde operations would be mandated to be conducted no closer than 12 miles from foreign land, and five miles from US land.

On these flights, there is always a slight, healthy tension between scientists, who want to get as close to storms as possible, and the flight crew, who has to put safety first.

While Zipser pressed for the penetration of storms, Capt. Slover responded that they would not be penetrating an anvil or flying under one in the presence of hail. The mission would avoid any yellow returns painted by radar. Today’s CPEX Mission would avoid yellow returns by 10 miles and 5,000ft. Anti-icing would be activated for 30 minutes after exiting clouds.

Regardless of planning, a lot of flexibility and time was built into the schedule due to the inherent unpredictably of the weather.

Doors would be closed at 12:30 for a projected takeoff at 13:00.

As for final housekeeping matters, Mission Director Chris Jennison lay down a few ground rules:

We were to be on headsets for communication as the DC-8’s platform is a noisy environment. Anyone wishing to shoot flash photography was to contact the Mission Director prior to shooting due to it being mistaken for lighting, an electrical arc, and, hence, fire. If anyone was feeling queasy, they were not to be shy about deploying the barf bags. An infirm user wouldn’t be the first, but crew, computers, and instruments don’t respond well to ‘lost lunch’. And finally, a quirk of the elderly DC-8:

“Please turn off the water faucet in the lavatories as they don’t turn off themselves.”

Wheels Up… or Not?


After nearly three hours of egress training and pre-flight briefings, the moment of truth arrives. We were shuttled onto the ramp to meet our DC-8 time machine.

As we embarked, most of the crew were already seated at work stations while others were taking their places in the 32 1980s 2-2 configuration First Class seats. We were instructed to ignore the overhead bins and, instead, bungee tie our belongings to latches behind each seat.

What became immediately apparent beyond all the instrumentation were the exposed wiring, ductwork, and sound insulation with some sidewalls removed. This translated into a very loud cabin. Carrying on a conversation while not on headphones was difficult at best.

The most striking clue that we were on a DC-8 was the massiveness of the windows—much larger than those of any jetliner of today, except for the Boeing 787. Douglas opted for larger windows spaced further apart instead of the closer-spaced, smaller windows we know today.

Instead of shades or the original curtains, our plane had removable blackout inserts plugged into the windows. Very welcome were the two windows, featuring special distortion-minimizing optical glass to enhance photography.

Just aft of the flight deck, Mission Director Jennison, Assistant Flight Director Roosevelt Williams, and navigator Greg Pugh strapped into their workstations. indicating imminent departure.

The DC-8 flight deck reveals very few concessions to the current age. Nowhere is this more apparent than in the continuing existence of the Flight Engineer’s position. When the aircraft finally is converted to glass avionics, the FE position and station will remain intact.

I made my way up to the flight deck to assume my dream jump-seat position behind the left seat. At 12:45, the four CFM-56s spooled up for our mission. On the flight deck, I observed the crew going through their battery of checklists—confirming and reconfirming engine pressure readings, flap settings, hydraulic systems, of this ‘Jurassic-era’ beast.

With the aviation photographers’ lenses firmly trained on us, we taxied off the FBO ramp toward Fort Lauderdale’s 9,000ft Runway 10L for an easterly departure. The radar and ATC reported numerous storm buildups in the area, narrowing our departure window.

Just as we reached the threshold of the runway, a cascade of problems poured into the cockpit. Our multi-function display (MFD), showing radar, TCAS, and the moving map, had completely failed. The crew attempted to reboot the display and diagnose the problem. Minutes thereafter, the Number Two fuel tank gauge on the FE station indicated a potential fuel leak with a loss of 5,000lb of fuel since spool-up. The crew radioed for a visual inspection. Luckily, there was no visual confirmation of a leak. With the weather closing in and equipment failing, a mission scrub started to look disappointingly like a definite possibility.

With no choice, we were cleared to do a quick taxi down the runway and turn off the first taxiway back to the FBO ramp. Terrence Dillworth, the tech guru of the Flying Laboratory, might yet save the seventh CPEX mission of the year in Fort Lauderdale.

Thanks to his engineering prowess, he was indeed able to repair the MFD unit, which was suspected of being affected by the tropical moisture, and confirmed that the fuel leak was just a false indicator. All of this was briskly accomplished without the DC-8 ever switching to ground power.

Showtime!


With all systems go, we taxied back out at 14:00. Eight minutes later, FE Mark Crane pushed forward the throttles of the four CFM-56s. We quickly gathered speed, beginning our cacophonous 28s takeoff roll. Capt. Slover pulled back on the yoke at 133kt and we pointed skyward.

I was sitting in the jump seat behind the Captain. It was incredibly loud but seemingly effortless. The light DC-8 leaped enthusiastically into the air toward its initial cruise of 5,000ft for an instrument calibration check. The plane immediately turned north and then due west to avoid the storm cells building up over the Atlantic Ocean.

While most planes avoid convective activity, NASA’s DC-8 directly confronts it. The safety and reliability of four CFM-56 engines eliminate the need for ETOPs and create additional confidence for the missions.

The seatbelt indicators were nearly immediately extinguished and the work began. First order of business: calibrating the instruments. About 23 minutes into the flight, with calibration complete and having cleared the weather in the low altitudes, we climbed to 10,000ft and turned east to rendezvous with our first target east of the Bahamas.

At 12,000ft, we were handed off to Miami Center and the analog autopilot was switched on. Throughout the flight, we would toggle communications between NYC Oceanic and Miami Center.

En route to our first target, as we climbed through FL230 up to our ultimate cruising altitude of FL310, we could clearly see towers of cumulonimbus clouds building rapidly—exactly what we had come for. We began flying our pattern of a series of left-hand turns and then right-hand turns as we circled the storms in the first target box area.

At this point, we began to fly through bands of precipitation, with the Pilots skirting the tops of the yellow returns painted on the radar by at least 1,000ft. The chop increased noticeably, the Pilots pulled back a bit on the 380nm TAS, and small ice crystals began to build on the windscreen.

The Pilots and crew seemed to be absolutely nonplussed at the moderate turbulence as this was just business as usual. The cockpit was a busy place as this geriatric but young-at-heart airplane demanded to be hand flown as much as possible. The analog autopilot was only used for altitude, not heading.

The only concessions this steam cockpit makes to the modern age are the Honeywell TrueVue radar, MFD, FMS, radios, and an iPad EFB displaying real-time flight plans and weather.

Fasten You Seatbelts


As we entered an area of disturbed weather, I made my way into the cabin to find  very busy, intense scientists at their workstations. There was no lull; every second in the lifespan of a storm counts for measurement. As promised, the cabin was very loud, exceeding 90dB.

The contrast provided by a 1960s-era aircraft loaded with cutting-edge 21st Century technology was striking.

Although there was no connectivity to the ground to surf the Web or email, Wi-Fi routers were installed throughout the cabin. These enabled anyone on a personal device or at a workstation to monitor flight instruments, weather radar, satellite photos, flight parameters, moving maps, scientific mission archives, and the multiple cameras trained on the cockpit and outside of the aircraft. This nifty piece of tech connectivity exceeded any moving map or in-flight entertainment systems I had ever used on a commercial flight.

The MASC science teams at mid-ship were measuring water vapor and temperature. Aft of them was the DAWN team, who were profiling wind velocity and direction at different slices of altitude. In effect, they were able to slice the storm and profile it, seeing updrafts and downdrafts in real-time. This is an operation best observed in the air via the radar from a safe distance rather than by penetrating the storms directly.

Towards the rear of the fuselage, the crucial and fascinating dropsonde part of the mission began. At his workstation, Mark Beaubien, of Yankee Environmental Systems, loaded each of his 25 dropsondes into what looked like a pneumatic tube protruding from the floor.

At US$1,000 per drop, these don’t come cheap but they are crucial to the mission. The dropsondes measure seven parameters, transmitting them back to the plane in real-time: horizontal wind speed, vertical wind speed for downdrafts, pressure, temperature, wind direction, relative humidity, and sea surface temperatureh

It takes 260s for the free-falling dropsondes to reach the ocean surface from 30,000ft. They hit the water at 30mph. During their descent, they transmit four packets of data per parameter per second. The durable drop sondes can actually transmit for a short duration after they hit the water.

In the very rear of the airplane, the scientist manning HAMSR was measuring the temperature and water vapor below us at different levels all the way to the surface. However, these readings tend to get less accurate as the altitude decreases.

After three hours, the crew routed the aircraft north to our second target box. The scientists asked to reduce altitude to FL280 to take more accurate wind measurements and requested the Pilots to get as close as possible to the building storm cells. The flight crew complied, but stayed clear of any hail or severe weather, never putting the aircraft at risk.

Their fingers must have calluses with all the waypoints they have to input almost continuously into the FMS. At 18:18, the decision was made to RTB (return to base). CPEX Program Co-Leader Chen said over the internal comm, “We got lucky today. We had a convective system that held together for a long time. It’s begun to dissipate, so we’re able to return.”

As the mission wound down, the cabin took on a calmer air. The descent began at 18:55. The instruments were secured and Nadir 7—a number of ports and windows for the instruments, such as the LIDR, were closed.

One of NASA’s DC-8 certified crews after another successful mission in South Florida.

Mission Director Jennison polled each team member on the mission’s outcome. A few jokes emit from the cockpit about the near-scrubbing of the mission. “The plane wasn’t happy about sitting in the rain for three days with nowhere to go, so perhaps she is trying to tell us something.”

At 5,000ft, the flaps were noisily deployed in stages, ultimately to a maximum of 50 degrees on the way to Fort Lauderdale’s Runway 10R. The fully extended flaps made for a beautiful sight. The air brakes caused the plane to buffet noticeably but the decrease in speed rewarded all onboard with a very gentle landing at 19:22.

Thrust reversers came on, slowing the N817NA at a relatively gingerly pace before it finally turned off the runway and returned to the FBO. There was no applause or back slapping. There was no time for that. It was time for the post-flight debriefing. And the next mission was scheduled to begin the next morning at 07:00.

There are still storms to chase and a veteran DC-8 ready, willing, and able to chase them.

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About Author

Chris Sloan

Chris Sloan

Aviation Journalist, TV Producer, Pursuer of First & Last Flights, Proud Miamian, Intrepid Traveler, and Did I Mention Av-Geek? I've Been Sniffing Jet Fuel Since I was 5, and running the predecessor to airwaysmag.com, Airchive, Since 2003. Now, I Sit in the Right Seat as Co-Pilot of Airways Magazine and airwaysmag.com. My favorite Airlines are National and Braniff, and My favorite Airport is Miami, L-1011 Tristar Lover. My Mantra is Lifted From Delta's Ad Campaign from the 1980s "I Love To Fly And It Shows." chris@airwaysmag.com / @airchive

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