Douglas DC-3D accident at Bristol, Tennessee, 28 Feb 1954

Accident narrative

On February 28, 1954, a Piedmont Airlines Douglas DC-3D struck a tree during an instrument approach to Tri-City Airport in Bristol, Tennessee. The crew maintained control, executed a missed approach, and diverted to their alternate airport in Winston-Salem, North Carolina. None of the three crew members or six passengers were injured, but the aircraft sustained substantial damage.

**The flight**

Flight 83 was a scheduled service from Norfolk, Virginia, to Knoxville, Tennessee. After a routine stop in Lynchburg, Virginia, the Roanoke segment of the flight was cancelled due to weather, and those passengers deplaned. The aircraft departed Lynchburg at 1949 on an Instrument Flight Rules (IFR) flight plan for Tri-City Airport. The aircraft's weight and center of gravity were within approved limits.

At 2059, Air Route Traffic Control cleared the flight to the Tri-City Range to descend to 7,500 feet. At 2110, approach control cleared Flight 83 for an Instrument Landing System (ILS) approach. The local weather was reported as a 600-foot precipitation ceiling, obscuration, three-quarters of a mile visibility, and light snow.

Shortly after, the flight reported that precipitation static was preventing reception of the compass locator at the outer marker and requested clearance to Winston-Salem. The crew reported they were receiving the locator and were again cleared for the ILS approach to Tri-City.

The flight reported crossing the outer marker inbound at 1,500 feet and advised they would circle to cross it a second time. Three minutes later, they reported crossing the outer marker inbound at 3,200 feet. The crew advised they were pulling up after "hitting the ground" and requested clearance to Winston-Salem.

En route to the alternate, the crew encountered left engine roughness and smoke in the cockpit, caused by oil from the damaged engine dripping onto the exhaust manifold and entering through the heater duct. The crew shut off the heaters, the smoke dissipated, and a normal landing was made in Winston-Salem at 2215.

**What the investigation found**

Investigators found the aircraft had struck a 60-foot tree, not the ground. The tree was located 7,500 feet from the approach end of Runway 27 and 1,300 feet to the right of the localizer course. The top of the tree was 319 feet below the glide path. The impact severed the upper ten feet of the tree and damaged the aircraft's left engine, left propeller, and the leading edge of the left wing. Examination of the aircraft and ground facilities revealed no evidence of structural failure, mechanical malfunction, or facility errors prior to impact.

According to company procedures, an ILS descent inbound should begin at the outer marker after an outbound procedure turn at 3,000 feet. The crew stated they made their procedure turn at 7,500 feet and crossed the outer marker inbound at that altitude, which was too high to intercept the glide path. They then made a right 360-degree descending turn, crossing the marker a second time at 3,200 feet.

The crew stated that after passing the marker, they maintained 120 m.p.h. with a descent of no more than 535 feet per minute. The captain stated he checked his descent at an indicated 2,200 feet, retracted the landing gear, and removed carburetor heat. According to the crew, a severe downdraft with moderate turbulence then forced the aircraft below the glide path until the left wing struck the tree.

The Board's weather analysis indicated smooth air to light turbulence below 5,000 feet. The inflow of cold air behind a recently passed cold front had stabilized the lower levels, precluding the formation of severe downdrafts. The Board found it improbable that a single severe downdraft forced the aircraft downward several hundred feet.

Instead, the Board noted that the captain's approach did not follow the company's flight manual. Both passes over the outer marker were higher than the glide path interception altitude, and the 360-degree turn did not allow sufficient time or distance to establish a stabilized course or airspeed. The Board believed it was more probable that, finding the aircraft nearly 500 feet above the glide path at the outer marker, the descent was steepened to intercept it, causing the aircraft to pass through and below the glide path.

Furthermore, the Board noted that if the captain had maintained the airspeed and descent rate he described, the aircraft would have remained well above the tree. The impact point 1,300 feet to the right of the localizer course also demonstrated that the aircraft had deviated seriously from its intended path.

**Probable cause**

The Board determined that the probable cause of this accident was "the action of the pilot in not following the approved procedures for an ILS approach which resulted in the aircraft striking a tree."