Airport Site Selection, Runway Orientation and Obstacle Control

This homework assignment delves into the critical aspects of airport engineering, focusing on site selection, runway orientation, and associated operational considerations. The solution addresses the relevance of airport site selection, emphasizing its impact on facility development, expansion, environmental consequences, and cost management. It correctly identifies and interprets runway degrees, illustrating the standard notation used in aviation. The assignment further examines the usability factor of airports, justifying why a usability factor below 95% might be economically unfeasible. It then analyzes an aircraft landing scenario under low visibility conditions, accurately determining the corresponding ILS category based on decision height. The objective of obstacle limitation surfaces is also explained, highlighting their role in defining the aerodrome's boundaries and identifying potential operational hazards. Finally, the solution examines the design considerations for Paro International Airport in Bhutan, explaining how the airport's design minimizes cross-winds and obstacles, enabling safe operation in a challenging topographical environment. The student expresses a desire for further exploration of obstacle control, indicating a strong grasp of the concepts and a desire for deeper understanding.

1. Explain in your own words, why is airport site selection so relevant?
Ans: The airport site selection is relevant and crucial as the screening process undertakes
factors into consideration that have a serious impact on the facility development and
operations. Also, various other criteria of expansion, environmental consequences and
cost management play important part in the selection process (Kazda & Caves, 2015).
2. What are the degrees of the runway in the image above? How would you exactly read it?
Ans: The degrees of runway in the image indicate a 090 degree and 270 degree, as the
orientation differs by either 18 or 180 degrees. The runways would be read as runway 09
and runway 27.
3. Do you think it is worth running an airport with a usability factor lower than 95%? Justify
your answer.
Ans: From my understanding, the usability factor of airport below 95% is not worth the
cost and money, unless extremely necessary. Airport facilities incur heavy costs on
government funds and facilities lower than 95% are surely to have economic
implications. Unless there is no alternative option, this should be avoided, as even heavy
carries are not immune to the metrological conditions.
4. An Airbus 320 approaches to land at less than a 100 feet on a rainy and foggy day. Which
ILS category would that be?
Ans: Since the decision height or DH is less than 100ft., therefore according to The
International Civil Aviation Organization (ICAO), the ILS category of III A where
Runway Visual Range is greater than 700ft would be marked.
5. What is the objective of the obstacle limitation surfaces?
Ans: The main objective of the obstacle limitation surfaces is to identify the lower limits
of the aerodrome and mark the objects that may become obstacles in operations. They

also aid in drawing the 3D Obstacle free zone (OFZ) for transitions to and from runway
(Graham, 2018).
6. Paro Airport in Bhutan is known for its complex orographical and mountainous areas,
what is designed to minimize cross-winds and obstacles in this case?
Ans: The Paro International Airport in Bhutan is a 3900 ft long asphalt runway with a
single strip. Due to the complexity of the airport and minimal infrastructural facilities at
the airport, the government of Bhutan has opted for 18-20 seater Short takeoff and
Landing aircrafts with higher rates of service ceiling, climbing and manoeuvrability.
Small carrier size helps in transition to and from runway (Ashford, Mumayiz, Wright, &
Wiley-Blackwell, 2011). Charter planes are also permitted. Long runway and small
carrier size are the two factors of design for the airport that enables it to deal with the
typical topography.
7. After studying this week, what is your level of understanding of the studied lecture?
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2
3
4
8. Please, name one topic that requires additional explanation (if any)
Ans: Control of Obstacles is the one topic that I would like to explore in detail. Although
the course covered many of the aspects relating to the concepts of non-instrument
runways and Category I surfaces, but the topic has many possibilities when linked to
existing difficult airport cases. I would like to know more about these specific exemplary
cases and enhance my understanding.

References
Ashford, N., Mumayiz, S. A., Wright, P. H., & Wiley-Blackwell. (2011). Airport engineering:
planning, design, and development of 21st century airports. John Wiley & Sons.
Graham, A. (2018). Managing airports: an international perspective. Routledge.
Kazda, A., & Caves, R. E. (2015). Airport design and operation. United Kingdom: Emerald Group
Publishing.