NTSB Factual Report

HISTORY OF FLIGHT

On December 13, 1997, at 1545 central standard time (cst), a Piper PA-28-140, N5454S, piloted by a student pilot, was destroyed during a collision with a moving tractor-trailer truck and terrain while on short final approach to runway 26L (2,300' X 33' dry/asphalt) at the Sylvania Airport, Sturtevant, Wisconsin. Visual meteorological conditions prevailed at the time of the accident. The 14 CFR Part 91 instructional flight was not operating on a flight plan. The pilot was fatally injured. The flight departed Sturtevant, Wisconsin, at 1540 cst.

Witnesses said N5454S's main landing gear struck the semi-trailer truck's trailer. They said the airplane was approaching the runway from the east "...at a very low angle," according to the Racine County Wisconsin Sheriff's Department report. One witness said the airplane "...had a slight up and down jerky movement as it crossed the northbound traffic just before hitting the semi [that was driving in the southbound lane]." Another witness said that the "...airplane was flying low toward the ground and as it got closer it looked as if it hit turbulence because it sort of swerved lower and hit the top right of a semi-truck. Then its wing skidded off the truck... ."

Witnesses reported that the airplane collided with the ground in a pitch down attitude with the right wing lower than the left wing. They said the airplane rebounded and slid backward about 20-feet from its impact point. The initial ground collision point was about 100-feet west of the highway where the truck was operating.

OTHER DAMAGE

The air deflector on the semi-trailer truck cab roof was cracked and had black marks on it. The trailer's front had a black imprint on it. The imprint consisted of two main sections. One section had the letters N, E, and R. These were arranged next to each other in a curved line. The second transfer mark paralleled the three letter's curve. The top of the trailer had 3 cuts in it. These cuts were between 6 and 12-inches long. The driver side of the trailer had an inward bend that was about 2-inches out of alignment with the trailer's side. The center of this was next to the area of cut marks.

PERSONNEL INFORMATION

The pilot was a student pilot who began her flight training on April 26, 1997. At the time of the accident, the pilot's logbook showed she had 37.3 hours of flight time. The pilot's logbook showed she had 26.6-hours of flight instruction and no solo flight time in a Cessna 150 before transitioning to the Piper PA-28-150 (PA-28). She had 1.6-hours of solo flight time in the PA-28. The pilot had 9.1-hours of dual instruction in the PA-28 series airplanes. She soloed the PA-28 after she had received 3.1- hours of flight instruction. The logbook showed she had received instruction in the following areas and sequence: "Touch-goes, stalls, aircraft system orientation (.9-hour flight instruction), crosswinds [takeoff and landings], 190/18 with gusts, go-around (.7- hour flight instruction), simulated power failure with landing, landings and takeoffs- looking good (1.0-hour flight instruction), 5 dual [takeoff and landings], 5 solo landings (1.0-hour total time, .5-hour solo)."

AIRCRAFT INFORMATION

N5454S was a 1971 model of the Piper PA-28-140 series airplane. According to its airframe logbook, the airplane's main landing gear tires were installed "new" on it during June 21, 1996. According to the mechanic who changed the tires, they were an "Aero Trainer" brand. The airplane was delivered from the factory with the shoulder harness mounted as found in the wreckage. The airplane was certified under Civil Air Regulations Part 3 on October 31, 1960. A review of CAR 3 revealed no requirements for shoulder harness mounting. A review of 14 CFR Part 23 revealed no mounting requirements for a shoulder harness.

Piper Aircraft Corporation issued Service Bulletin Number 896 on November 28, 1988. Piper stated it "...considers compliance mandatory." According to the bulletin, the compliance time should "...not exceed 1 calendar year from the date of this Service Bulletin." The Bulletin's purpose says that Piper supports the use of shoulder harnesses with lap belts. The Service Bulletin said that Piper is issuing the "...Mandatory Service Bulletin and strongly urges you to install and use a complete restraint system of both seat belts and shoulder harnesses... ." A copy of this Bulletin is appended to this report.

The shoulder harness kit directions for airplane serial numbers that N5454S is part of shows that the harness should be installed in the cockpit ceiling about 14-inches aft of the fuselage's side window post. A search of Service Bulletins, Service Letters, did not reveal any that addresses changing the factory installed belts that were mounted similar to the one found on N5454S. A copy of the shoulder harness kit instructions is appended to this report.

WRECKAGE AND IMPACT INFORMATION

The on-scene investigation revealed that N5454S's landing gear legs were sheared off at the wing's main spar attachment point. The nose landing gear oleo strut separated at the strut mount. The trailer's top was about 14-feet above the highway. N5454S's collision point with the trailer was about 300-feet east of the runway's threshold. The runway has a displaced threshold that is 140-feet in length. See illustration appended to this report.

N5454S's right leading edge of its wing tip was crushed aft and up from the chord line. The fuselage, forward of the firewall, was bent to the right about 15-degrees and crushed up about 8-inches above the top of the firewall. This area was pointing downward at an approximate 30-degree angle from the firewall. The crush area was on the bottom of the nose bowl and right side of the cowl. The right side of the fuselage was crushed inward about 8-inches midway between the wing's trailing edge and the stabilator's leading edge. The stabilator's right side was twisted upward from its tip to root area. The assembly was crushed aft about 6-inches.

The left side of the instrument panel was compressed inboard and forward about 4-inches. The right handle of the pilots control yoke was broken off at the hub of the yoke. No other deformation of the instrument panel or occupiable space within the cockpit was observed.

The propeller had gouges in its leading edge from the tip to about 7-inches in toward the blades root. The gouges varied in depth from about 1/8-inch to 3/4-inch. The lengths of these gouges were between 1/4-inch and about 1-inch. No anomalies with the airframe, flight control system or engine were found that would prevent flight.

METEOROLOGICAL INFORMATION

Weather reported at the Kenosha Municipal Airport, Kenosha, Wisconsin, on December 13, 1997, at 1550 central standard time were a clear sky, visibility of 10-statute miles with winds from 260-degrees magnetic at 6-knots. According to an astronomer from the Adler Planetarium, Chicago, Illinois, the sun's position at the time of the accident was 235-degrees from magnetic north and was 4.2-degrees above the horizon. The astronomer's statement is appended to this report.

AERODROME INFORMATION

The accident airport is privately owned but open to public use. The State of Wisconsin has designated the airport as a reliever airport for general aviation aircraft using Mitchell International Airport located in Milwaukee, Wisconsin.

The Milwaukee, Wisconsin, Federal Aviation Administration Flight Standards District Office Principal Operations Inspector said his office has had complaints of low flying airplanes by drivers on the interstate highway that is about 300-feet from the runway's threshold. The displaced threshold begins about 160-feet from the interstate highway. During subsequent investigation activity, the IIC observed airplanes flying about 20 to 50-feet above the vehicles that were using the highway as the airplanes approached to land. Some airplanes landed on the displaced threshold. The displaced threshold markings on runway 26L were weathered and very light in color.

MEDICAL AND PATHOLOGICAL INFORMATION

The pilot's autopsy was conducted on December 14, 1997 at the Milwaukee County Wisconsin Medical Examiner's Office by Dr. John R. Teggatz. The toxicological examination was conducted by the FAA's Civil Aeromedical Institute on March 11, 1998. The toxicological report showed 2.900 (ug/ml, ug/g) Lidocaine detected in the blood sample. There was no other drugs, carbon monoxide, cyanide, or volatiles found during this examination.

SURVIVAL ASPECTS

According to the Survival Factors Group Chairman's report, the pilot sustained "...traumatic chest injuries." This report continues by saying, "The [Medical Examiner's] report stated that the pilot's injuries resulted from the pilot's chest contacting the control yoke of the airplane. Evidence of the pilot's seatbelt usage was documented in the [Medical Examiner's] report as follows: Contusions were present over both iliac crests, and a poorly-defined somewhat band like injury to the anterior aspect of the left upper arm was present." The Group Chairman's report continues, "The autopsy report did not document any injuries to the pilot's left clavicle nor any patterned abrasion of the left shoulder."

ADDITIONAL INFORMATION

The pilot's seat was found mounted on its track and capable of fore and aft movement. The pilot's shoulder harness was mounted to the cockpit's sidewall 4-inches aft of the vertical window post and 3 1/2- inches below the fuselage's rear side window ledge. The diagonal-design shoulder harness was mounted to the sidewall at a 30.6-degree angle (from the horizontal axis) behind and below the top of the pilot's seat back. The rescue personnel had cut the shoulder harness and seat belt to remove the pilot from the cockpit.

According to a Federal Aviation Administration Advisory circular, AC No. 21-34, entitled Shoulder Harness-Safety Belt Installations, "...improper attachment of the diagonal shoulder belt to a buckle situated near the center of the pelvic region. The shoulder belt is no longer diagonal across the occupant's body. The shoulder belt passes low and to the side of the center of mass of the upper torso, so that in a severe accident the torso may twist around the belt and even slide out of the belt." A search of the FAA's Airworthiness Directives (AD) revealed no AD that addresses changing the mounting position of the shoulder harness to comply with this AC.

The pilot had been flying at Mitchell International Airport, Milwaukee, Wisconsin. The runways most often used at this airport for flight training were 3,163' X 100' and 4,182' X 150-feet. The runway at Sylvania Airport is 2,300' X 33'. According to the textbook, "Human Factors in Flight," by Frank Hawkins, runway width differences may be a source of distortion in perception during landing. When the runway is narrower than normal the pilot may experience an illusion that causes them to fly a lower than normal final approach path.

A human performance specialist from the FAA's Civil Aeromedical Institute, AAM-510, who is part of the Flight Crew Performance section, stated that this happens because the pilot is trying to match the mental site picture of the wider runway to the narrow runway. By flying lower the site picture begins to resemble the wider runway. The book, entitled "Flightdeck Performance, The Human Factor," by David O'Hare and Stanley Roscoe states, "Some researchers have suggested that if the width and/or length of an unfamiliar runway differs radically from that to which the pilot is accustomed, then the resulting illusion may cause systematic deviation above or below the desired glidepath." An excerpt from this book appended to this report.

The IIC discussed the potential airplane and highway vehicular traffic conflict and suggested the State of Wisconsin and airport owner provide usable glide path guidance for pilots landing on runway 26L. A workable visual approach slope indicator (VASI) was identified that could be easily installed and maintained. This information was passed on to the State officials and the airport owner. A copy of this information is appended to this report.

A letter from the Wisconsin Bureau of Aeronautics said: "We have begun preliminary discussions with the department's Office of Transportation Safety. This office should address the glideslope indicator and its installation due to the multimodal benefits. We have placed the Sylvania Airport into a list of candidates for our Airport Marking Program. Completion of runway marking will be after the installation of the glideslope indicator system." A copy of this letter is appended to this report.

NTSB Probable Cause

The pilot's misjudgment of altitude/distance and her failure to maintain adequate visual lookout. Also causal was the pilot's failure to maintain adequate obstacle clearance. A contributing factor was the pilot experiencing a visual illusion.