Preventing Vehicle-Aircraft Incidents During Winter Operations and Periods of Low Visibility (2008)

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A runway incursion is more likely to occur at controlled air- ports when the exact location of an aircraft or vehicle on the airport surface is unknown or contrary to an ATCT instruc- tion. ATCT controllers are constantly reminded of their need to monitor the location and progression of the aircraft and vehicles operating on the airport surface, in accordance with instructions issued, to provide assurance of separation. At uncontrolled airports, a safety hazard or runway incursion is more likely to occur when proper procedures are not followed by pilots or by ground operators. One study that sought to identify the factors associated with incursions or surface incidents focused on ATCT controllers. It identified the most common factor for errors (27%) was the controller “forgetting” something. Forgetting about an air- craft (e.g., holding in position or on approach) contributed to 15% of the errors; 5% were related to the controller for- getting that a runway was closed; and 3% of the errors were the controller forgetting about a vehicle on the runway. The remaining 4% involved the controller forgetting something else, such as a local procedure (26). A case example from the FAA follows: In daylight IMC, with Runway Visual Range reported at 3,000 ft, a B737 captain—just after touch down—observed the amber rotating beacon on a vehicle about 1,000 ft. ahead on the runway. The captain made an immediate “go-around” and missed the eight vehicles by an estimated 10 feet. What happened? While the aircraft was about 15 miles SW of the airport and being vec- tored for a runway 36 Cat II approach, the local controller had given the ground controller permission for snow removal equip- ment to proceed north on runway 36 and to exit runway 36 at the intersection of Runway 27L. The aircraft reported at the outer marker and was cleared to land with no further conversa- tion between controllers about the status of the snow removal equipment. (27, p. 32) Forgetfulness is not the sole domain of ATCT controllers, as airport maintenance and operations personnel can be just as forgetful, perhaps not of equipment on the airfield, but where they are located and of procedures or requirements that must be followed. Vehicle operators have a responsibility to maneuver their vehicles on taxiways and runways in accor- dance with ATCT instructions. As a cause of errors, loss of SA is discussed further in chapter six. The FAA Office of Runway Safety has identified through- out its literature common factors for why incursions occur. 12 The following are some of the contributing factors that have been identified: • Failure to follow established standardized procedures, • Failure to understand the implications of one’s actions or inactions, • Lack of training and practice to internalize procedures, • Loss of SA, • Failure to ask for help when confused, • Failure to use the airport diagram, and • Unfamiliarity with the airport. When the questionnaire asked airport operators what factors they had experienced or thought would increase the risk of collision, the response was wide ranging and inclusive. The most common factors identified by survey respondents were poor communication, poor visibility, and fatigue. The factors identified represent the varying nature of airport operations at different categories of airports. The following chapters pro- vide a synopsis of the type of factors identified in the survey responses, and they are grouped accordingly. COMMUNICATION Airport operator responses to the questionnaire cited multiple times that poor communication was a primary factor affect- ing the risk of collision. Poor communication included failed or miscommunication with the ATCT and other crew mem- bers, lack of communication of the snow plan or of ATC traffic advisories, and confusion about radio communications. Contributing to poor communication are radio-related factors that could have a basis in human factors, communication tech- niques and processes, or equipment operation. They include monitoring or using an incorrect radio frequency or the wrong radio, inoperative radio equipment, dead batteries, frequency congestion, failure to switch frequencies, or noise. The dis- semination, or lack thereof, of safety-related information through the NOTAM system was also cited as a contributor to poor communication. Dissemination of safety-related infor- mation, proper communication protocol, and operator distrac- tion is discussed in more detail in chapter three of this report. ENVIRONMENT Classified under environmental conditions are factors encoun- tered during winter operations such as changing weather and CHAPTER TWO FACTORS AFFECTING COLLISION RISKS

13 extreme conditions (wind chill, wind gusts, blowing snow and whiteout conditions, heavy versus light snow), night oper- ations, pavement surface conditions (presence of ice, glycol resulting in poor traction), and airfield congestion (vehicles and aircraft). The factor cited the most as increasing the possible risk of collision during winter operations was poor visibility. This includes fog, freezing rain, or blowing snow conditions, and reduced visibility due to snowbanks and obscuration of markings, signs, and lights. Addressing issues associated with visibility restrictions and winter conditions is discussed in chapter four. HUMAN PERFORMANCE The second most cited factor affecting possible risk of collision during winter operations was fatigue—not just of the vehicle operators—but of ATCT controllers and others. However, fatigue is a symptom having many different contributing factors. Pressure from air traffic controllers, pilots, and tenants to open or keep open operating surfaces, complacency from working long hours, sleep deprivation, sensory overload, distraction and lack of SA, too much radio chatter, operator inattention, repetitiveness of activity, operator attitude, phys- iological needs, vehicle ergonomics, and human error all are human factors that can grouped into the human performance category. Chapter five of this report provides a synopsis of the effects of fatigue during winter operations, with the infor- mation being limited to that of a primer on the contribution that fatigue can have on possible error and incursion-producing effects, and not an exhaustive presentation of its effects. SITUATIONAL AWARENESS SA has many definitions (28). Basically, it is a continuous process of attentiveness and surveillance that results in an accurate perception of the factors and conditions affecting an individual and his or her environment during a defined period of time. Essentially, SA refers to an individual’s assumptions about how they feel, where they are located, the condition of their equipment, the abilities they have, what they thought they heard or meant to say, and myriad other factors that affect the outcome of any situation. SA was cited as a factor numerous times in survey responses. However, it becomes more apparent when one reads accident or V/PD reports that either a loss of SA or not having SA at all was a major factor in the event. SA is discussed in more detail in chapter six. TIME PRESSURES Frequently mentioned as a collision risk factor were pres- sures associated with maintaining operations. This includes not having adequate time to complete a trip down the runway, inadequate notice to get off a runway, length of time to gain access to a runway for snow removal, aircraft being autho- rized to taxi into position for takeoff while snow crews were performing final cleanup operations, tenants constantly call- ing inquiring when the surfaces will be open, aircraft running behind schedule, and organizational pressures to serve the customer by keeping the airfield and terminal areas open. Pres- sures associated with opening a runway or maintaining runway operations are discussed in chapter seven. PERSONNEL, VEHICLES, AND EQUIPMENT RESOURCES The survey respondents identified not having enough vehicles, equipment, or personnel as factors. Having vehicles and equip- ment that were operational throughout the winter event also was a concern, even though airports certificated under 14 CFR Part 139 are required to have programs to ensure vehicle readi- ness. The speed of vehicles, the heightened visibility through lighting and marking of vehicles, and the type and placement of brooms and plows were cited as potential collision risk factors. Equipment factors also refer to the airfield facilities, such as proper signage and lighting being available and oper- ational. The design of vehicles was implicated in the ques- tionnaire responses by reference to a particular design factor, such as comfortable seats, lighting, control layout, heating, and wiper blade action. Vehicle design is addressed more specifically in chapter eight. OPERATIONAL FACTORS Survey respondents identified factors that, while they could fall under some of the other categories, are best grouped under the heading of operational factors. This includes equip- ment not normally on runways or other operating surfaces during aircraft operations, non-routine vehicle and aircraft traffic patterns causing congestion, operations being con- ducted without ATCT assistance, changes in airfield config- uration due to wind changes or snow blockage of movement areas, and the utilization of new or inexperienced employees or contractors. Operational factors also include failure to follow standard procedures, an oft-cited factor in the survey responses. As pre- viously discussed, airports serving air carrier operations are required to have snow plans approved by the FAA as part of the certification manual. It is a best practice for airports to update the SICP as part of their pre- and post-winter reviews. Less than adequate or failure to follow snow plans, ground vehicle operating procedures, or vehicle operator training programs can lead to winter operation incidents. Additionally, winter operation incidents can be created by inadequate or nonexistent procedures associated with NOTAM issuance and posting, incomplete self-inspections, lack of proper super- vision, poor or slow response to conditions, vehicles not staying together, personnel not watching for other vehicles or aircraft, and inadequate information about approaching winter conditions. Chapter nine delves more into how airports manage these operational factors.

SUMMARY Chapter two provides an introduction into the factors affecting the risk of collision during airport winter operations. Accord- ing to the literature, the more common possibility for a safety hazard or runway incursion to exist occurs when the exact location of an aircraft or vehicle on the airport surface is unknown or is contrary to an ATCT instruction; when either 14 controllers, pilots, or vehicle operators forget about a critical safety activity; or when proper procedures are not otherwise followed by controllers, pilots, or ground operators. Chapter two further presents an outline of the remaining chapters of the report. Presented in chapters three to nine are more detailed analyses and explanations of the research on the factors affecting collision risks during airport winter operations.