WEATHER IMPACTS ON AIRPORT OPERATIONS

1. WEATHER IMPACTS ONAIRPORT OPERATIONS DUSTIN HARBAGE Lead Forecaster NWS Jackson, KY Airline Rated Pilot 11/14/01

2. Airport Operations • Operations vary at airports due to weather conditions. • As weather lowers from VFR to LIFR the options available to controllers change and become more limited. • These reduced options require increased separation between aircraft and hence fewer aircraft takeoffs and landings per hour.

3. Critical Altitudes • There are several critical altitudes in and around the airport. • Each airport is different based on: • Available runways • Available approaches • Runway configuration • Traffic density • Noise restrictions

4. Natrona Co InternationalCasper WY

5. Casper Pg 2

6. Casper Airport

7. CPR ILS 3 Airport information Frequencies Plan View Side view Airport diagram Approach Minimums

8. Wichita Mid-Continent Wichita, KS Airport Elevation Pattern Altitude

9. Los Angeles, CA

10. LAX Pg 2

11. LAX Airport

12. Chicago O’Hare Airport Notice that Chicago has three (3) sets of parallel runways!

13. Omaha, NE

14. OMA Pg 2

15. DEN ILS 17L

16. DEN ILS 17R

17. ICT ILS 19R

18. ICT LOC BC 19L

19. OMA ILS 14R

20. OMA ILS 14R CAT II

21. OMA ILS 14 R CAT III

22. OMA NDB or GPS

23. LAX Visual 24 L/R

24. LAX Visual 25 L/R

25. The most obvious and least restrictive weather for an approach would be VFR • Here aircraft can be sequenced in for landing as soon as they can identify the preceding aircraft. • This may be before they can see the airport, as in the case of LAX. • If the weather goes below VFR but remains above the Final Approach Fix altitude then the aircraft can be vectored to a point where they can located the airport and/or the preceding traffic.

26. If the weather goes below the Final Approach Fix altitude but remains above the traffic pattern altitude. • Aircraft can be vectored to a point where they can safely enter the traffic pattern and complete a visual pattern and landing (If one is available). • Each individual aircraft would supply their own separation from preceding aircraft.

27. When the weather decreases to below pattern altitude then instrument approaches must be flown. • Separation from preceding aircraft is provided by approach control. • The type of approach is determined by: • Approach availability, • Aircraft instrumentation, • Pilot certification, • and Weather.

28. When an airport has multiple runways it has other operational options. • It may sequence aircraft towards intersecting runways with timing separation to keep them from arriving at the intersection simultaneously • If parallel runways are separated by 1 mile or more then they can use a staggered approach sequence. • If parallel runways are separated by 3 miles or more then they can use simultaneous approaches.

29. The major factor for an airport is that no two aircraft can be on the same runway (even at different ends) at the same time. • Sequencing aircraft for arrival or departure is based on being able to get one aircraft off the runway before another touches down or begins a takeoff roll. • The lower the weather the greater the separation required between aircraft to achieve the one aircraft per runway rule.