This article is part of a longer feature by Phil Parker for Cathay Pacific Airways Crews News. Some minor details apply specifically to Cathay Pacific Airways Operations.
Final Approach Director
Need
Traffic volume usually drives the creation of new sectors and procedures: this was the case for Hong Kong and the FAD. When traffic volumes increase the issue is not so much planning time (even though important) but frequency congestion. When a frequency gets too busy Controllers cannot pass instructions and clearances at the optimum time and efficiency always drops. Efficiency however inevitably becomes more important during peak traffic periods. Splitting APR into APR and FAD solves the frequency congestion problem and APR has more time for planning the sequence order. The FAD handles arrivals for the last few miles and concentrates on efficient and accurate final spacing.
Technical
FAD operates (119.5 Mhz) 09:30 to 23:00 Local but we sometimes open it at other times for short periods when necessary. You will talk to FAD from about 25 NM (Runway 07) to 35 NM (Runway 25) from touchdown. APR transfers aircraft to FAD at 6000 ft altitude and 220 Kts spaced about 7 Nm from the aircraft ahead by default. APR varies the transfer conditions depending on the circumstances: don’t be surprised if you get something different.
Experience
Hong Kong has progressively reduced the default spacing between arrivals over the last few years. FAD has enabled us to increase capacity, contain holding and delays, and avoid slowing arrivals early. Controllers have enough frequency and planning capacity to control arrivals more accurately. In theory our arrival capacity has increased by 40% since 1999: a significant increase in efficiency. The default in-trail distance between two Heavy arrivals reduced from 6 NM to 4 NM. More SIERA arrivals get short tracks and we operate higher speeds (280 Kts) through MELON and MANGO.
The recent introduction of procedures to switch arrivals to the South runway during peak periods leverages FAD and APR capacity. All arrivals benefit because we aim to use minimum RADAR separations (3 NM) between North and South runway arrivals. Cargo, BAC, and some South Apron arrivals also get a shorter route to their stand.
Controllers achieve minimum separation distances with a leading North runway arrival easier than with a leading South runway arrival: no wake turbulence separation requirements. The North arrivals must cross behind the South arrivals and wake turbulence separations may apply.
You may get more speed instructions and vectors than before because FAD fine tunes a sequence for optimum efficiency.
Crews
So what can crews do to ease their way through this part of the Hong Kong ATC system?
Please keep radio calls concise and don’t report speeds or headings unless asked to by the previous controller. Hong Kong operates a tactical flow system that uses speed and in-trail spacing to regulate traffic between sectors. The speed issued by one controller applies until changed by another where we use the phrase ‘.. until advised.’. Hong Kong Sectors co-operate rather than work independently.
If you cannot follow a speed instruction tell us what IAS will work for you and we’ll arrange the sequence accordingly. Only stating that you can’t fly a speed wastes time on the frequency without providing us with useful information. If your aircraft has a higher or lower weight than usual then warn us on the APR frequency: we will expect a different final speed than normal.
As Cathy pilots you fly Heavy category aircraft. Hong Kong traffic includes a significant number of Medium and the occasional Light category aircraft. We often issue vectors and speeds to you to create the correct gap behind your aircraft. The reason for our instructions may not always be obvious or in front of you.
Accurate speed control ensures correct spacing between arrivals: change the speed of your aircraft without delay when instructed. The difference between a efficient minimum separation arrival stream and a loss of wake separation is a fine one. We can easily spot differences between an issued and flown speed of only 10 Kts.
Future
The interface between FAD and APR traffic will improve: too many arrivals level at 6000 ft instead of getting a continuous descent. Expect more descents below 6000 ft from APR before transfer to FAD as our procedures evolve.
In the next year the holds will start to move closer to the airfield. A shorter distance between a hold and a runway means that the system will react quicker to changes in demand. Our efficiency will improve again.
As traffic continues to increase (financial crises permitting) you can expect speeds inside 50 NM from touchdown to decrease.
We will give increasing attention to optimizing the arrival flow by grouping Medium Wake aircraft and sequencing these ahead of Heavy Wake aircraft.