 |
 |
 |
 |
| |
|||||
|
|
|
|
|
||||
Hands-on Testing in the Lab Moves Procedures Forward Randall Bone and Dave Domino 
efore the FAA approves new procedures for air traffic control, aviation stakeholders must work together and agree that the changes will be safe and effective. An example of how the ATM Lab can support key decision-makers is the development and testing of the Cockpit Display of Traffic Information (CDTI) Assisted Visual Separation (CAVS) concept. (This concept was formerly called CDTI Enhanced Flight Rules or CEFR.) The ability of the lab to provide "hands-on" interaction with the CAVS procedures was a critical step in building confidence among stakeholders that the concept was a clearly feasible implementation of CDTI technology. CAVS is designed as an extension of current visual approach and visual separation procedures. Visual separation requires the pilot of the following aircraft to sight the leading aircraft and then maintain a safe distance behind it during the rest of the approach and landing. In this procedure, the pilot assumes responsibility for separation from the aircraft ahead. (However, if a pilot loses sight of the airplane ahead, he or she must advise the controller who will then reassume responsibility for separation and may have to start using instrument approach procedures.) When air traffic controllers can use pilot-applied visual separation, the typical result is tighter spacing between landing aircraft than is possible when instrument approach procedures are used. In other words, more planes can land in a shorter amount of time when visual separation is used. The purpose of CAVS is to maintain airport capacity by delaying the transition from visual approach operations to instrument approach operations as weather conditions deteriorate. The CDTI supplements out-the-window visual contact and allows the pilot to lose sight of the aircraft ahead while still keeping it "in sight" on a traffic display. By expanding the weather conditions under which visual separation may be applied, airport capacity may be maintained and delays reduced. Despite its potential benefits, CAVS did not immediately win over all aviation stakeholders. Some air traffic controllers feared that CAVS was a move toward making pilots responsible for "self-separation" from all aircraft—a concept they did not find acceptable. Some people in the FAA standards community also expressed strong reservations about the use of CDTI for aircraft separation, including concerns about pilots accepting extra responsibility. CAASD played a major role in moving the CAVS concept toward acceptance, principally by bringing pilots, controllers, and others into the lab to fly the concept and test its strengths and weaknesses. We were able to work with stakeholders in real time to resolve misunderstandings about CAVS. It was important to make sure everyone witnessed and understood CAVS' Automatic Dependent Surveillance Broadcast (ADS-B) and CDTI technologies and their applications. We briefed the CAVS concept to pilots, controllers, and various aviation organizations. We also had regular contact with United Parcel Service, which has been planning to implement CAVS. These efforts helped the aviation industry understand the concept's potential and reduced the level of skepticism. The most powerful "myth-busting" tool, however, was the CAASD ATM Laboratory. Without the lab and its simulations, it would have been almost impossible to effectively communicate the CAVS concept and its benefits. We found that people who experienced the procedure by watching the simulations, or by actually flying the procedure in the ATM Lab cockpit (see photos above), had a much more positive view of CAVS than those who had only read about it. For example, one key FAA individual (also a pilot) who came to MITRE for a discussion of CAVS admitted to us that he had come in as a skeptic. After flying the CAVS simulation in our cockpit simulator, however, he left convinced that the procedure was worth further exploration. The lab also allowed us to gather feedback that would help us improve the CAVS concept. We evaluated the experiences of pilots and air traffic controllers who participated in a series of CAVS simulations and found that pilots were comfortable with the display features of the CDTI, were willing to accept responsibility for separation (as they do now with visual approach), and felt their resultant workload was acceptable. As a result of this research, and from stakeholder feedback, we determined that the aggressive original proposal for using CAVS during instrument approach procedures should be redefined as a long-term goal. For the near term, we recommended the use of CAVS during visual conditions with marginal visibility (e.g., five miles), where visual contact with the aircraft ahead may be lost temporarily, but the trail aircraft is always in visual conditions. This application was judged by most stakeholders as a more acceptable first step. It was the ATM Lab and its capabilities that helped mold CAVS into an operationally feasible concept. |
|||||
| For more information, please contact Randall Bone or Dave Domino using the employee directory. Page last updated: January 7, 2005 | Top of page |
|||||
Solutions That Make a Difference.® |
|
|
Download this issue [1.9 MB]