Plane & Pilot
Tuesday, October 8, 2013

Setting Stabilized Approach Criteria

Just because the FAA doesn’t get specific doesn’t mean you don’t need criteria

Radar data from the FAA at Albuquerque International Airport indicated that the airplane entered the AEG traffic pattern from an extended downwind, at approximately 205 knots ground speed and an altitude of 6,800 feet MSL (1,000 feet AGL). Over the next approximately three nm on a downwind path, the airplane slowed to 171 knots ground speed and had descended to 6,300 feet MSL (500 feet AGL).

The radar data indicated that the airplane's downwind path moved about 2,000 feet closer to the runway and was approximately 2,775 feet away from the runway, when the pilot started his base turn. The last radar return showed the airplane at 5,900 feet MSL and 180 knots.

An engineer with the NTSB analyzed the last 28 seconds of the flight and estimated the maximum rate of descent while turning from base to final was between 1,800 and 1,900 feet per minute. The calibrated airspeed was estimated as between 145 and 150 knots. The NTSB engineer estimated that the maximum bank angle was approximately 73 degrees.

The Double Eagle II Airport is uncontrolled, and at an elevation of 5,837 feet. It has two runways: 22-04 which is 7,400 feet long, and 35-17 which is 5,999 feet long. Runway 22 has an ILS with a Medium Intensity Approach Lighting System with Runway Alignment Indicator (MALSR). Runway 22 isn't equipped with any visual glide path indicators. The airport's manager told investigators that local procedures recommend that airplanes fly a 1,000 feet AGL traffic pattern altitude and that large and turbine-powered airplanes should enter the traffic pattern at 1,500 feet AGL.

An instructor who taught at a facility where the pilot received training told investigators he teaches that downwind speed for the PA-46-500TP should be 145 to 150 knots, base 130 knots and final 90 to 95 knots, with maximum bank angles in the pattern of 30 degrees.

The NTSB determined that the probable cause of this accident was the pilot's unstabilized approach and his failure to maintain obstacle clearance. Contributing factors were the dark night and the static wires.

Peter Katz is editor and publisher of NTSB Reporter, an independent monthly update on aircraft accident investigations and other news concerning the National Transportation Safety Board. To subscribe, write to: NTSB Reporter, Subscription Dept., P.O. Box 831, White Plains, N.Y. 10602-0831.


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