THE DTSB
The DTSB determines the Probable Cause of this accident to be the FAA, in that the accident pilot was cleared by FAA ATC for an RNAV GPS runway 28R approach, when the associated airport ASOS was out of service. FAA standard safety protocol requires that each pilot be in receipt of current weather and NOTAM information in order to be qualified to be issued an IFR approach clearance by that controller. The accident aircraft is a category B aircraft. The accident aircraft was being flown as single pilot, and it is likely that the accident pilot selected “APPR” mode on the Sperry AP/FD control panel after receiving his ATC approach clearance, fully intending to let the autopilot fly the GPS LPV 28 approach all the way down to landing. The Citation SII has four selectable flap settings. At the selection of full flaps, the aircraft likely ballooned slightly, and it is common to utilize the vertical speed thumb wheel to overcome the slight climb that was the result of the application of full flaps. Basically, the elevator pitch trim system cannot trim nose down fast enough to keep the aircraft exactly on the LPV glide path when full flaps is selected. After using the pitch wheel, the FMA would have annunciated VERT and it would have been necessary to re select “APPR” in order to restore maintaining the LPV electronic glide path. With the aircraft still in vertical speed and no alert possible, the aircraft continued descending below the LPV glidepath, unnoticed by the accident pilot, until it struck the 90 foot high tension powerlines, almost 250 feet below the LPV glidepath located in a neighborhood just prior to the runway. There is some indication that the accident pilot attempted a go around after the first point of contact, but that information is not yet confirmed. The contact with the power lines was the beginning of the accident sequence as the first point of contact. It is not likely that any equipment or altimeter malfunction, or inoperative runway lighting contributed to the accident. The FAA was clearly illegal, at fault, and financially liable for the loss of life and property by issuing an approach clearance for the approach when no weather or altimeter setting was available and there was no published alternate weather procurement procedure in place. The accident pilot held a valid CE-500 type rating for the Citation series and a valid third class medical. The Citation S550 is specifically “not” certificated for single pilot operations, but may be operated as such through the use of an established FAA exemption letter. It is still unclear if or when the accident pilot received single pilot exemption training. If single pilot training and exemption letter was in fact completed, the date would have been after 12/15/2024. It is not possible for exemption date data to be displayed on FAA data in any way. Contributing to the accident are the accident pilots decisions, lack of significant single pilot IFR jet experience, and likely fatigue.