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below 5,000 feet above the airport elevation. 

There are numerous exceptions to the high performance aircraft arrival procedures previously outlined. For example, in a non-radar environment, the controller may clear the flight to use an approach based on a NAVAID other than the one aligned with the landing runway, such as a circling approach. In this case, the descent to a lower altitude usually is limited to the circling approach area with the circle-to-land maneuver confined to the traffic pattern. 

IFR en route descent procedures should include a review of minimum, maximum, mandatory, and recommended altitudes that normally precede the fix or NAVAID facility to which they apply. The initial descent gradient for a low altitude instrument approach procedure does not exceed 500 ft/NM (approximately 5°), and for a high altitude approach, the maximum allowable initial gradient is 1,000 ft/NM (approximately 10°). 

Remember during arrivals, when cleared for an instrument approach, maintain the last assigned altitude until established on a published segment of the approach or on 

a segment of a published route. If no altitude is assigned with the approach clearance and the aircraft is already on a published segment, the pilot can descend to its minimum altitude for that segment of the approach. 

## Airspeed 

During the arrival, expect to make adjustments in speed at the controller’s request. When pilots fly a high-performance aircraft on an IFR flight plan, ATC may ask them to adjust their airspeed to achieve proper traffic sequencing and separation. This also reduces the amount of radar vectoring required in the terminal area. When operating a reciprocating engine or turboprop airplane within 20 NM from the destination airport, 150 knots is usually the slowest airspeed that is assigned. If the aircraft cannot maintain the assigned airspeed, the pilot must advise ATC. Controllers may ask pilots to maintain the same speed as the aircraft ahead of or behind them on the approach. Pilots are expected to maintain the specified airspeed ±10 knots. At other times, ATC may ask pilots to increase or decrease airspeed by 10 knots, or multiples thereof. When the speed adjustment is no longer needed, ATC advises the pilot to “… resume normal speed.” 

