On April 15, 2021, about 1030 central daylight time, a Gates Learjet Corp. 35A airplane, N354EF, was substantially damaged when it was involved in an accident near Colorado Springs, Colorado. The two pilots and two crew members onboard were not injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 positioning flight. According to the first officer, who was initially the pilot flying, they departed from Centennial Airport (APA), Denver, Colorado, for a short positioning flight to Colorado Springs (COS). After departure, air traffic control provided vectors to intercept the GPS approach for runway 17R at COS. The airplane exited the overcast cloud layer at an altitude of 650 to 700 ft above ground level and the first officer visually acquired the airport, realizing that the airplane was offset about ½ mile right of the runway centerline. The captain requested control of the airplane and then made the required course correction to line up with the runway centerline. This correction occurred about 1.5 to 2 miles from the runway threshold. About 100 ft above the ground, the captain reduced the throttles to "idle," was able to establish runway centerline, and continued the descent for landing. As the airplane descended through 10 to 20 ft above the runway, the captain reported that the "stick shaker" activated. The first officer was monitoring and announced "stall," and the captain advanced both throttles. Just before the airplane touched down, it experienced an un-commanded roll to the right and the nose dropped. The captain attempted to arrest the roll by applying left aileron, but the airplane did not respond in time and the right wing fuel tip tank impacted the runway surface just before the landing gear contacted the runway. The crew was able to maintain control throughout the landing roll and the crew taxied the airplane off the runway. The airplane sustained substantial damage to the right wing.
The operator stated that there was no mechanical malfunction or failure of the airplane.
The company operations manual stated:
V.4 Stabilized Approach Concept (ref. AC 120-71) It is essential that a stabilized approach to the landing runway be flown. A stabilized approach must be established before descending below the following minimum stabilized approach altitudes: 500 feet above the airport elevation during visual flight rules (VFR) or visual approaches and during straight in instrument approaches in VFR weather conditions. Minimum descent altitude (MDA) or 500 feet above airport elevation, whichever is lower, if a circling maneuver is to be conducted after completing an instrument approach. 1000 feet above the airport or touchdown zone elevation during any straight- in instrument approach in instrument flight conditions. 1000 feet above the airport during contact approaches. It is essential that the airplane touchdown in the first one-third of the available landing distance (ALD), but in no case greater than 3000 feet down the runway, whichever is less. If touchdown in the first one-third of the ALD, but in no case greater than 3000 feet down the runway is not assured, a rejected landing must be executed.
The Flight Safety Foundation Approach and Landing Accident Reduction Briefing Note, 7.1 – Stabilized Approach, listed one of the deviations in unstabilized approaches as:
Excessive flight parameter deviation when crossing the minimum stabilization height:
- Excessive speed - Not aligned with the runway - Excessive bank angle - Excessive vertical speed, or - Flight path above glideslope
The Briefing Note also stated that one behavior involved when unstabilized approaches are continued is excessive confidence in a quick recovery by postponing the go-around decision when flight parameters are exceeded.