Airline pilots skeptical of new avionics technology

Nov. 1, 1998
ANAHEIM, Calif. - The world`s airlines are being overwhelmed by new technologies that are undergoing every test and examination but one: will working pilots accept them?

By J.R. Wilson

ANAHEIM, Calif. - The world`s airlines are being overwhelmed by new technologies that are undergoing every test and examination but one: will working pilots accept them?

That assessment stunned an audience of engineers and avionics specialists at the Avionics 98 conference in Anaheim, Calif., on 22 September. The assessment, of the Communication-Navigation-Surveillance/Air Traffic Management (CNS/ATM) revolution, came from the conference`s opening day keynote speaker. The CNS/ATM encompasses the wide scope of the Future Air Navigation System (FANS).

Capt. Greg Saylor, systems manager-technical requirements for Delta Air Lines flight operations in Atlanta, said most conferences on FANS talk about everything except what goes on in the cockpit. Line pilots, meanwhile, have a diversity of opinions - but a commonality of concerns - about such operational issues as self-separation, controller/pilot data link communications (CPDLC) and the impact of a mixed-equipage environment.

"Is CDTI [cockpit display of traffic information] adequate to the task? Where will it be integrated?" Saylor asks, in reference to the concept of self-separation, in which flight crews - not air traffic controllers - determine the time and distance between aircraft in flight. "We haven`t seen an acceptable answer yet. And until we can get our hands on a device, actually work with it, go to the boss and say `I`ve used this and it works` - it will never happen."

CDTI would display information for nearby aircraft such as ground reference points and navigation information to increase a pilot`s situational awareness. The idea of using CDTI to give pilots the information they need to fly aircraft closer together than they can today was first investigated in the 1970s by researchers at MIT and later at NASA`s Langley Research Center. Separation between aircraft is typically five miles in en-route airspace and three miles in terminal airspace.

While that effort found pilots liked having the information available, it also found they had a tendency to fixate on the CDTI display to the detriment of scanning the instrument panel and the airspace outside the aircraft. They also found problems with determining the actual speed of an aircraft ahead, thus forcing pilots to compensate by slowing down far too early.

The overall results were disappointing and CDTI technology was not pursued, although some of the location data were later incorporated into the Traffic Alert Collision Avoidance System (TCAS) cockpit display the FAA mandated for airliners. TCAS plays no role in proposed approach sequencing.

With FANS, the CDTI concept has been resurrected, but Saylor says he finds the new incarnation no more convincing 20 years later.

"There seems to be very little effort [to assess the impact of] the transfer of the ATC workload to the cockpit," he says. "Why do we want to do that? We haven`t heard a good reason. Even if it does happen, how do we know pilots won`t apply even larger buffer zones than ATCs do? I`ve seen no research attempting to answer that question."

The Delta pilot voiced even greater concerns about the controller/pilot data link, which would replace the current voice communications between ATCs and pilots with printed information appearing on a display screen in the cockpit. These communications would use VHF radio channels over the U.S. and HF radio channels over oceans.

"CPDLC transfers responsibility for communications from our voices and ears to our hands and eyes. We already navigate with our hands and eyes, so this is a significant change in cockpit procedures," Saylor points out.

The danger lies in losing the current "two-thread" system in which the pilot and co-pilot hear the same information at the same time and can confirm what they heard with each other.

In a CPDLC environment, only the pilot not actively flying the aircraft will see the datascreen, then will read that information to the pilot flying. Any misstep in that single thread would be propagated into the air system.

"So far, we just aren`t comfortable with this," Saylor said on behalf of the pilot community. "We do think the idea of synthetic voice uplink is a good idea [so long as the synthetic voice itself is clear]."

CPDLC is gaining support elsewhere within the air transportation community, however. Oceanic CPDLC, using a satellite data link, already is in limited use by the U.S. and several other Pacific Rim countries.

A study by the MITRE Corporation`s Center for Advanced Aviation System Development in McLean, Va., concluded:

"The process of transcribing routine clearances or instructions by voice is prone to human error and makes inefficient use of the available radio channels. Since modern cockpits increasingly include significant automation capabilities, it seems clear that most of the routine clearances and instructions could be composed automatically (or nearly so), approved by the responsible air traffic controller, and forwarded to a cockpit display via data link. Indeed, human factors experiments suggest that this approach can increase the efficiency with which the air traffic controllers operate, reduce communication errors, improve the efficiency with which the airspace is managed, and reduce pilot workload."

But Saylor says pilots disagree. Pilots believe, he says, that CPDLC ultimately will increase cockpit workload and increase the potential for error by taking one pilot out of the direct communications link. Even if that does not constitute a major problem in a routine flight, it could be extremely serious in an emergency situation, he says.

Airline experts also must have answers to several questions before they would consider CPDLC to make economic sense, he adds, such as whether pilots could use while flying close to major airports, and whether engineers can retrofit it to old aircraft.

"Will the airlines voluntarily equip with it?" he asks. "Some airlines say if the big carriers do it, they won`t have to because it will be nice and quiet on the radio waves."

The question of mixed equipage among - or even within - airlines also raises concerns with costs and the ability of a reconstituted ATC system to handle it. Under any circumstances, he predicts, the makeup of commercial avionics will be mixed for years to come. Even majority conversion to these new systems may not be possible without regulatory requirements, especially given the questionable economic justification for retrofitting old aircraft at a time when the FAA is mandating other expenses such as new data recorders and wiring inspections.

While Saylor`s emphasis was on man-in-the-loop concerns, his references to airline economic concerns echoed those of a Boeing committee. The Boeing group conducted an "Economic Evaluation of CNS/ATM Transition" and concluded "the lack of consideration of the economics of transition to the new operational concept has slowed the pace of the implementation process."

Avionics innovation these days must have a strong justification. "The era of `technology for technology`s sake` is past," the committee writes. "As an example, during the development of the 747-400, a series of aircraft changes were offered to customers as an avionics upgrade package. Over 50 functional enhancements were contained in that package, including GPS integration, Aeronautical Telecommunications Network (ATN), CPDLC, Automatic Dependent Surveillance (ADS), Company Data Link and a host of flight crew requested functions. Very few airlines bought the package and thus it was later withdrawn. The airlines felt that the lack of mature benefits coupled with the cost could not justify the purchase of the package. The economic case suffered because of the absence of parallel infrastructure developments to support realization of the operational potential of ATN and other advanced features."

Many of those elements are integral parts of the CNS/ATM plan, but without regulatory agencies requiring them to install such systems, the evidence is that many airlines will not do so voluntarily - at least, not in the near future.

"How will ATC handle mixed equipage? Most studies in the U.S. have assumed a 90 percent level, but I think it will be many years before we even reach 50 percent," Saylor warns. "If only one aircraft without CPDLC arrives at Dallas-Forth Worth, it would have to be handled with kid gloves to slip into the stream of self-separated aircraft. How great will the resulting disruption be?"

Saylor emphasizes he is not presenting a Luddite point of view - although he acknowledges there are some pilots who will reject any new technology out of hand. He is, for example, a strong supporter of Delta`s decision to install head-up displays (HUDs) as original equipment on 71 new ordered Boeing 737-800s.

"We believe HUD is a major safety enhancement in all phases of flight - and the closer to the ground you get, the more important it becomes," he says. "A conformal display and velocity vector can give the pilot a safe approach to any airport in the world under all landing conditions. Delta would like to put a HUD in every cockpit, but that`s too big an elephant to handle right now, but we are committed to it in our new 737s."

And that was why the 737 was designated as the first aircraft to receive HUDs, he says.

The HUD Delta has ordered (including options for an additional 380 Boeing 737-800s and 24 options each for new 767-400s and 777s) is the Head-Up Guidance System (HGS) from Flight Dynamics of Portland, Ore., a joint venture of the Rockwell Collins Air Transport Division in Cedar Rapids, Iowa, and Kaiser Aerospace and Electronics in San Jose, Calif. The HGS 4000 was specifically designed for Delta to work interchangeably with all of the Boeing aircraft it has optioned for HUD installation.

Saylor`s primary plea to the conference was to involve line pilots - not just former pilots now in management - in the development and decision-making process to a far greater extent than has been done in the past. If that is done, he adds, airlines such as Delta almost certainly will make pilots - although probably not aircraft - available.

At that moment, an FAA representative in the audience noted the government does have aircraft for such purposes and would welcome the participation of working pilots.

Even so, Saylor warns the avionics, ATC, and regulatory communities against misinterpreting airline involvement in such programs: "Airline participation in special committees, groups and forums is NOT a commitment to equip."

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