NTSB Factual Report

On June 17, 2016, about 1709 eastern daylight time, a Piper PA-28-236, N8161X, sustained substantial damage during landing roll out at the Punta Gorda Airport (PGD), Punta Gorda, Florida. The private pilot and the two passengers were not injured. The airplane was registered to a private company and operated by the pilot. A visual flight rules flight plan was filed for the personal flight that departed Peter O. Knight Airport (TPF), Tampa, Florida, about 1630 and was destined for PGD. Visual meteorological conditions prevailed for the personal flight conducted under the provisions of 14 Code of Federal Regulations Part 91.

The pilot stated that he was cleared by air traffic control (ATC) to land on runway 22, a 150-foot-wide runway. During the landing roll, the airplane suddenly departed the left-side of the runway and ended up in the grass. The pilot initially thought he had blown a tire, but when he exited the airplane he noticed an Allegiant Air McDonnell-Douglas MD-83 parked on the movement area of Taxiway A2 performing a maintenance test run of its engines. He told the control tower that he thought he had been blown off the runway by the MD-83's jet blast.

Prior to the accident, a maintenance crew for Allegiant Air had requested clearance from the control tower to taxi to the intersection of taxiway A and A2 to conduct a run-up of its engines. Upon arriving at the intersection of taxiway A and A2, the maintenance crew realized that the prevailing wind was from the west and not conducive to a successful engine run-up and asked the tower if they could reposition facing the wind. Due to the width of taxiway A, about 60-feet-wide, the MD-83, a 146-foot-long airplane, could not complete a 180° turn on taxiway A and had to proceed to the approach end of runway 22 and then down the runway to taxiway A2. Upon reaching taxiway A2, the maintenance crew reported clear of runway 22. The MD-83 was positioned on taxiway A2 facing away from runway 22 into the prevailing wind, heading approximately 270°. This resulted in the engines of the MD-83 being directed toward the first third of runway 22 and its resultant engine exhaust being positioned closer to the runway than if it had conducted an engine run-up from taxiway A.

After the MD-83 was in place to start the engine run-up, the control tower cleared the accident airplane to land on runway 22, but did not warn the pilot of the parked MD-83 or that it was conducting a test-run of its engines as required per Federal Aviation Administration (FAA) order 7110.65, Air Traffic Control, paragraph 3-1-5, Vehicles/Equipment/Personnel Near/On Runways. After the excursion, when the pilot told the tower that he encountered jet blast from the MD-83, a controller queried the crew of the MD-83. The maintenance crew advised that they had not started the engine test yet and had not advanced the engines beyond idle. The controllers said they did not think it was possible that the MD-83 had an effect on the accident airplane going off the runway and entered the event into the control tower logs as loss of control event on the airplane's account with no mention of the MD-83.

The accident airplane had a belly-mounted camera that recorded the runway excursion. The video displayed a normal landing and rollout on the runway centerline. When the airplane was about 1,700 ft down the runway, it showed the MD-83 ahead and to the right just as the right wing lifted and the airplane departed the left side of the runway. Photographs taken of the airplane after the accident revealed the left wing spar was bent.

A review of Allegiant's MD-80 Aircraft Maintenance Manual, jet engine exhaust velocity contours at idle power can reach 35 miles per hour (mph), or about 30 knots, at a distance of 100 ft behind the aircraft centerline. The wind was 270° at 9 knots (10.3 mph). This would have resulted in the accident airplane encountering a sudden and unexpected right crosswind of nearly 45 mph, or about 39 knots.

According to the air traffic controllers on duty at the time of the accident, the control tower's air traffic manager (ATM), and the airport's Director of Aviation, engine run-ups were usually conducted on taxiway A or on taxiway D between the approach end of runway 4 and 33; however, the location of engine run-ups was not specified by airport, ATC, or Allegiant Airline company procedure. The location for an engine run-up was determined by the on-duty controller, who based the location on existing traffic and weather conditions. Following this accident, the Punta Gorda Tower Standard Operating Procedures, (SOP), PGD Order 7210.3 appendix O, Special Problem Areas, was modified in order to proceduralize the engine run-up process at PGD for transport category airplanes. The modifications stated, in part:

Clearance Delivery/Ground Control Potential Problem Areas:

3. Use caution when approving run-ups for turbo jet aircraft. Run-ups (anything above idle) may only be approved in areas that do not direct jet exhaust across an active/advertised runway or taxiway. Situate aircraft requesting cross bleed starts, or run-ups away from any other aircraft or hold taxiing aircraft away from aircraft in question (taxiway Delta and carrier ramp).

Local Control Potential Problem Areas:

8. Use caution when approving run-ups for turbo jet aircraft. Run-ups (anything above idle) may only be approved in areas that do not direct jet exhaust across an active/advertised runway or taxiway. Situate aircraft requesting cross bleed starts or run-ups away from any other aircraft or hold taxiing aircraft away from aircraft in question (taxiway Delta and carrier ramp).

These procedures were disseminated to Allegiant Airlines and the air traffic control tower.

FAA order 7110.65, Air Traffic Control, which outlines air traffic control procedures and phraseology for use by personal providing air traffic control services, Paragraph 3-1-5, Vehicles/Equipment/Personnel Near/On Runways, stated:

A. Vehicles, equipment and personnel in direct communications with the control tower may be authorized to operate up to the edge of an active runway surface when necessary. Provide advisories as specified is Paragraph 3-1-6, Traffic Information.

B. Ensure that the runway to be used is free of all known ground vehicles, equipment, and personnel before a departing aircraft starts takeoff or a landing aircraft crosses landing threshold.

Paragraph 3-1-6, Traffic Information, states is part:

A. Describe vehicles, equipment or personnel on or near the movement area in a manner which will assist pilots in recognizing them.

B. Describe the relative position of traffic in an easy to understand manner such as "to your right" or "ahead of you."

Paragraph 3-3-3, Timely Information, states in part:

Issue airport condition information necessary for an aircraft's safe operation in time for it to be useful to the pilot. Include the following, as appropriate:

A. Construction work on or immediately adjacent to the movement area.

B. Rough portions of the movement area.

C. Braking conditions caused by ice, snow, slush, or water.

D. Snowdrifts or piles of snow on or along the edges of the area and the extent of any plowed area.

E. Parked aircraft on the movement area.

F. Irregular operation of part or all of the airport lighting system.

G. Volcanic ash on any airport surface area and whether the ash is wet or dry (if

known).

H. Other pertinent airport conditions

NTSB Probable Cause

The tower controller’s failure to identify and mitigate jet blast from an airplane conducting an engine test run, and the effect of the jet blast on landing traffic, which resulted in a runway excursion when a landing airplane encountered the blast. Contributing to the accident was the lack of procedures for positioning high-powered airplanes conducting engine test runs in the airport movement area.