Controllers Turned Plane To Avoid Collision

From the NTSB's Preliminary Report on the crash of Piper Navajo N40731 near San Antonio International Airport on November 14th:

On November 11, 2004, approximately 1718 central standard time, a Piper PA-31-350 twin-engine airplane, N40731, registered to and operated by Dash Air Charter Inc., of San Antonio, Texas, was destroyed when it impacted a multi-unit residential building and the ground following a loss of control while on an instrument approach to runway 3 at the San Antonio International Airport (SAT), San Antonio, Texas. The commercial pilot and four passengers were fatally injured. Instrument meteorological conditions (IMC) prevailed, and an instrument flight plan was filed for the Code of Federal Regulations Part 91 personal flight. The cross country flight originated from the Dodge City Regional Airport (DDC), near Dodge City, Kansas, approximately 1345, and its final destination was SAT.

According to information provided to the NTSB investigator-in-charge (IIC) by friends and family members, the passengers on board the aircraft were returning home after a hunting trip. Preliminary information provided by the FAA and weather reporting services revealed that the en route portion of the flight from Dodge City was flown in instrument meteorological conditions. There were no reports of problems from the aircraft during the approximate 3 1/2-hour en route portion of the flight. As the aircraft neared its destination of San Antonio, the pilot established communications with San Antonio Air Traffic Control Tower (ATCT) and maneuvered to execute the Instrument Landing System (ILS) Runway 3 approach. The following are excerpts of radio communications between the pilot of the aircraft (N40731) and approach controllers (ATCT) in the minutes prior to the accident. In the excerpts, ATCT controllers identify the aircraft as "Navaho seven thirty one."

ATCT: Navajo seven thirty one, turn left heading zero nine zero
N40731: Left turn, zero nine zero
ATCT: Navajo seven thirty one, descend and maintain, disregard, just three thousand five hundred for
Navajo seven thirty one, heading zero nine zero
N40731: Three thousand five hundred, zero nine zero
ATCT: Navajo seven thirty one, is three miles from RESOC, turn left zero six zero, three thousand five
hundred till RESOC, cleared I L S runway three, maintain max forward speed
N40731: Ok, left zero six zero, join localizer, maintain three point five till RESOC
ATCT: Navajo seven thirty one, San Antonio
N40731: Yes
ATCT: Navajo seven thirty one, looks like you lost the localizer, turn left heading two seven zero, climb
and maintain three thousand five hundred
N40731: Left turn two seven zero, three thousand five hundred
ATCT: Navajo seven thirty one, say altitude.
N40731: Climbing to three thousand
ATCT: Say altitude now
N40731: Two thousand five hundred
ATCT: Navajo seven thirty one, looks like you are in a left turn northeast bound, traffic one o'clock and a
mile, hard left turn now, heading three zero zero, hard left turn
ATCT: Seven thirty one, maintain three thousand five hundred, I show you at one thousand eight hundred
ATCT: Navajo seven thirty one, I lost your transponder.

No further communications were received from the aircraft.

The ILS RWY 3 approach can be initiated via a radar vector to intercept to the final approach course at 4,000 or 3,500 feet MSL depending on the location of the vector. The initial approach fix for the approach (RESOC) has a designated altitude of 3,500 until established on the 3.00 degree glide slope. The final approach fix (FAF) for the approach is located 5.4 miles from the runway threshold. The decision height for approach was 986 feet MSL (200 feet height above touchdown) and is based on flying the full ILS with a fully operational ILS receiver. The published missed approach procedure for the approach is to climb to 1,700 feet MSL, then execute a climbing left turn to 3,500 feet MSL, heading 025 degrees, then proceed outbound via the SAT R-040 to SHEPE Intersection/SAT 18.4 DME and hold.

Preliminary radar data received from the FAA showed that the aircraft remained initially left of the localizer course line before turning right of the localizer approximately 2 miles before the final approach fix (FAF). Radar then showed the aircraft turn to the left of course line. When the aircraft was abeam the FAF, it was approximately 1 mile left of the course line. As the aircraft closed to approximately 1.5 miles from the runway threshold, the aircraft had veered about 1.3 miles left of the course line (at which time ATCT instructed the pilot to turn left to a heading of 270 degrees). The aircraft continued to turn left through the assigned heading and appeared to be heading back to the ILS course line. According to the radar, another aircraft was inbound on the ILS course line and ATCT instructed the pilot to turn left immediately. Thereafter, the aircraft went below radar coverage (approximately 1200 feet MSL).

A witness, located approximately 1.25 miles northwest of the accident site, reported to the NTSB investigator-in-charge (IIC) that he heard a very loud noise, and then observed a small white airplane flying toward a building, approximately 60 feet in height. The airplane pitched up approximately 45 - 90 degrees just before the building and disappeared into the clouds. A second witness located approximately 1 mile northwest of the accident site reported to the IIC that he heard a low flying aircraft, and then observed a white twin-engine airplane banking left out of the clouds. The airplane leveled out, and flew into the clouds again a few seconds later. The witness added that he "saw no indications of problems, smoke, or visible damage to the airplane." The witness stated that the airplane was at an altitude of 100-200 feet above the ground. A third witness located adjacent to the accident site reported that they heard the sound of a low flying airplane in the distance. As it became louder and louder, they looked up and observed the airplane in a near vertical attitude as it impacted trees and the side of an apartment complex.

At 1732, the automated surface observing system at SAT reported wind from 050 degrees at 9 knots, visibility 4 statute miles, cloud condition overcast at 400 feet, temperature 54 degrees Fahrenheit, dew point 51 degrees Fahrenheit, and an altimeter setting of 30.29 inches of mercury.

FMI: www.ntsb.gov