Publication Date


Document Type


Committee Members

Jennie Gallimore (Advisor), Subhashini Ganapathy (Committee Member), Clark Shingledecker (Committee Member)

Degree Name

Master of Science in Engineering (MSEgr)


Data-Link Communication, or DataComm, is a digital text messaging system providing a means of communication between Air Traffic Control (ATC) and pilots. Current Pilot/ATC communication is via voice radio, but the number of ATC operators and voice channels are finite, which limits the number of aircraft voice transmission can accommodate. The number of aircraft within the National Airspace System (NAS) is expected to double between 2004 and 2025, and a transition from voice to DataComm is a necessity. DataComm is an integral part of the NAS and is implemented in incremental phases increasing its functions and capability. There are many advantages with DataComm including providing the ability to send a digital message to a specific plane, the ability to send a long and detailed message with accuracy, as well as providing a platform to add additional features after initial implementation. However, DataComm does have critical integration issues into the current avionic systems and flight deck for commercial airliners. In an attempt to limit the number of DataComm transmissions and to support trajectory based operations, future ATC clearances are expected to increase in length and complexity. Pilots will be required to first understand the clearance, and then decide whether it is acceptable. Clearances that are rejected prompt pilots to create a Downlink Message (DM) to ATC to negotiate clearances. Pilots may also initiate a clearance request with ATC. This research focuses on DM creation after pilot evaluation of complex multi-element clearances depicted via text and graphics on a Navigation Display (ND). Two separate touchscreen DM creation interfaces were developed. The research was broken into two separate experiments. All scenarios were presented on a dynamic flight simulator connected to a simulated ATC station. Experiment I was an exploratory study and recorded response time to interpret a clearance, pilot accuracy, and time to create a DM. A Pilot/ATC communication interface (TextGen) was utilized during Experiment I. TextGen was a menu-based system that allowed pilots to create their own DMs by selecting messages from categories on a touchscreen. Graphics of the DM were presented on a ND in correlation to the original ATC clearance as DMs were constructed. Twenty-Four pilots were tested on ten separate concatenated clearances repeated four times each to comprise a total of forty clearances. Half of the clearance scenarios were designed so that the pilot should reject and half were designed to be acceptable. Verbal comments from Experiment I helped formulate recommendations to improve DataComm interfaces for future implementations within the NAS. The results showed that TextGen was time consuming, required excessive input, and demanded 100% of the pilots' attention during interaction. Experiment II had four separate hypotheses and recorded response time to interpret a clearance, pilot accuracy, and times to create a DM. Experiment II tested two separate Pilot/ATC DM creation communication interfaces. One format was TextGen, (tested in Experiment I), and the second was a direct manipulation graphic interface called AutoGen. AutoGen allowed pilots to create DMs by physically touching graphics that were depicted on a ND. The clearance variables within the DM were automatically altered in correlation with the graphic manipulation. Experiment II compared DM creation time, and response time to interpret a clearance between both presentation formats. Eight separate pilots were tested on both formats. Results indicated that AutoGen allowed pilots to perform more accurately with less time. The average time to create a DM was significantly less when pilots interacted with AutoGen compared to TextGen. Pilots overwhelmingly preferred the AutoGen interface because of the intuitiveness of the display, ease of use, and automatio...

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Department or Program

Department of Biomedical, Industrial & Human Factors Engineering

Year Degree Awarded