Standard Terminal Arrival Routes (STARs)
A STAR is an ATC-coded IFR route established for application to arriving IFR aircraft destined for certain airports. A STAR provides a critical form of communication between pilots and ATC. Once a flight crew has accepted a clearance for a STAR, they have communicated with the controller what route, and in some cases what altitude and airspeed, they fly during the arrival, depending on the type of clearance. The STAR provides a common method for leaving the en route structure and navigating to your destination. It is a preplanned instrument flight rule ATC arrival procedure published for pilot use in graphic and textual form that simplifies clearance delivery procedures.
The principal difference between standard instrument departure (SID) or departure procedures (DPs) and STARs is that the DPs start at the airport pavement and connect to the en route structure. STARs on the other hand, start at the en route structure but do not make it down to the pavement. This is primarily because STARs serve multiple runways and sometimes multiple airports.
STARs greatly help to facilitate the transition between the en route and approach phases of flight. The STAR will end at a fix or NAVAID, designated by ATC, which allows for radar vectors and/or to connect to an instrument approach procedure. The objective when connecting a STAR to an instrument approach procedure is to ensure a seamless lateral and vertical transition. The STAR and approach procedure should connect to one another in such a way as to maintain the overall descent and deceleration profiles. This often results in a seamless transition between the en route, arrival, and approach phases of flight, and serves as a preferred route into high volume terminal areas. [Figure 3-10]
STARs provide a transition from the en route structure to an approach gate, outer fix, instrument approach fix, or arrival waypoint in the terminal area, and they usually terminate with an instrument or visual approach procedure. STARs are included at the front of each Terminal Procedures Publication (TPP) regional booklet.
For STARs based on conventional NAVAIDs, the procedure design and obstacle clearance criteria are essentially the same as that for en route criteria, covered in En Route Operations. STAR procedures typically include a descent gradient of about 318 ft/NM, or about three degrees. The descent gradient on a STAR will have to vary to meet altitude restrictions, if any, along the particular route. Altitude restrictions are frequently necessary for airspace and air traffic restrictions. The design guidance for a new or revised STAR is in FAA Order 8260.3, published in March 2016. Some published STARs were designed under the previous guidance in FAA Order JO 7110.9. The new guidance requires a more shallow descent gradient for the last part of the STAR. In addition to descent gradients, STARs allow for deceleration segments at any waypoint that has a speed restriction. As a general guideline, deceleration considerations typically add 1 NM of distance for each 10 knots of speed reduction required.
RNAV STARs or STAR Transitions
STARs designated RNAV serve the same purpose as conventional STARs, but are only used by aircraft equipped with FMS or GPS. An RNAV STAR or STAR transition typically includes flyby waypoints, with fly over waypoints used only when operationally required. These waypoints may be assigned crossing altitudes and speeds to optimize the descent and deceleration profiles. RNAV STARs often are designed, coordinated, and approved by a joint effort between air carriers, commercial operators, and the ATC facilities that have jurisdiction for the affected airspace. RNAV STAR procedure design, such as minimum leg length, maximum turn angles, obstacle assessment criteria, including widths of the primary and secondary areas, use similar design criteria as other RNAV procedures. Likewise, RNAV STAR procedures are designated as either RNAV 1 or RNAV 2, based on the aircraft navigation equipment required, flight crew procedures, and the process and criteria used to develop the STAR. The RNAV 1 or RNAV 2 designation appears in the notes on the chart. RNAV 1 STARs have higher equipment requirements and, often, tighter required navigation performance (RNP) tolerances than RNAV 2. For RNAV 1 STARS, pilots are required to use a course deviation indicator (CDI)/flight director, and/or autopilot in LNAV mode while operating on RNAV courses. (These requirements are detailed in Chapter 1 of this book, under RNAV Departures.) RNAV 1 STARs are generally designated for high-traffic areas. Controllers may clear a pilot to use an RNAV STAR in various ways.
If the pilots clearance simply states, “cleared HADLY ONE arrival,” the pilot is to use the arrival for lateral routing only.
- A clearance such as “cleared HADLY ONE arrival, descend and maintain flight level two four zero,” clears the pilot to descend only to the assigned altitude, and then should maintain that altitude until cleared for further descent.
- If the pilot is cleared using the phrase “descend via,” the controller expects the pilot to use the equipment for both lateral guidance and altitude restrictions, as published on the chart.
- The controller may also clear the pilot to use the arrival with specific exceptions—for example, “Descend via the HARIS ONE arrival, except cross BRUNO at one three thousand then maintain one zero thousand.” In this case, the pilot should track the arrival both laterally and vertically, descending so as to comply with all altitude and airspeed restrictions until reaching BRUNO, and then maintain 10,000 feet until cleared by ATC to continue to descend.
- Pilots might also be given direct routing to intercept a STAR and then use it for both lateral guidance and altitude restrictions. For example, “Proceed direct MAHEM, descend via the MAHEM TWO arrival.”