Aviation Accident Summaries

Aviation Accident Summary CHI08FA027

Browerville, MN, USA

Aircraft #1

N327ND

PIPER PA-44-180

Analysis

The accident flight was the third of a three-leg dual instructional night cross-country flight. The airplane was established in normal cruise flight at 4,500 feet mean sea level (msl) when the airplane abruptly departed controlled flight and impacted a bog. The bog was about 15 to 20 feet deep, with a thin layer of vegetation floating on the surface. The airplane came to rest inverted, and damage to the airframe was consistent with an inverted impact to the surface of the bog. Data recovered from the airplane's flight display system indicated that the airplane was in stable flight on a 320-degree magnetic heading, at 4,500 feet msl, and approximately 160 knots true airspeed prior to the accident, when it abruptly departed from controlled flight. The airplane rolled approximately 20 degrees left wing down, yawed to the left about 30 degrees, and simultaneously pitched nose-down about 40 degrees. It then reversed and immediately entered a descending, right roll for the duration of the flight. The airplane impacted the bog within 30 seconds of the upset. The post accident examination noted that the left half of the horizontal stabilator was bent upward approximately 90 degrees, inconsistent with the damage to the remainder of the airframe. This damage was consistent with the initial left yaw and nose down pitch recorded during the upset. In addition, a depression and tear were observed on the upper wing skin near the left wing tip. Microscopic examination and DNA testing of material on the inside surface of the wing skin was identified as remains of a Canada goose. The natural history of this species was consistent with the location, time, and date of the accident.

Factual Information

HISTORY OF FLIGHT On October 23, 2007, about 2212 central daylight time, a twin-engine Piper PA-44-180, N327ND, operated by the University of North Dakota, was substantially damaged during an in-flight collision with terrain near Browerville, Minnesota. The dual instructional flight was being conducted under Title 14 Code of Federal Regulations Part 91 on a visual flight rules (VFR) flight plan. The private pilot and flight instructor were fatally injured. Night visual meteorological conditions prevailed at the time of the accident. The cross-country flight departed St. Paul Downtown Airport (STP), St. Paul, Minnesota, at 2115. The intended destination was Grand Forks International Airport (GFK), Grand Forks, North Dakota. The pilot and flight instructor planned a three-leg, dual instructional, cross-country night flight as part of the University of North Dakota (UND) commercial/instrument flight program. The initial leg was from GFK to Hutson Field Airport (GAF), Grafton, North Dakota. From GAF, the flight planned to fly to STP before returning to GFK. The pilot contacted flight service at 1711 and filed two VFR flight plans. The first was for a flight from GAF to STP, with a proposed departure time of 1815. The second was for the return flight from STP to GFK, with a proposed time off of 2115. A Direct User Access Terminal (DUAT) session attributed to the flight was initiated at 1713. The flight departed GFK about 1745, and made an intermediate stop at GAF before continuing to STP. At 1825, the flight crew contacted Grand Forks Automated Flight Service Station (AFSS) and requested that their VFR flight plan to STP be activated. The flight arrived at STP at 2000, and it subsequently departed on the accident flight at 2115. At 2125, the flight crew contacted Princeton AFSS and requested that their VFR flight plan from STP to GFK be activated. According to employees at the fixed base operator (FBO) at STP, the arrival and departure of the UND flight was uneventful. The flight crew seemed relaxed. The FBO customer service representative recalled that the pilots borrowed the crew car in order to get something to eat. At the request of the flight instructor, the airplane was topped-off with 41.8 gallons of 100 low-lead aviation fuel. At 2118, after departure from STP, the flight crew contacted the Federal Aviation Administration (FAA) Minneapolis Terminal Radar Approach Control (TRACON) facility and requested VFR flight-following services en route to GFK. Handling of the flight was subsequently transferred to Minneapolis Air Route Traffic Control Center (ARTCC), which provided flight-following services until 2155. At that time, the flight was approaching the extent of normal radar coverage and the flight-following services were terminated. The airplane was approximately 13 miles north of St Cloud, Minnesota, at 4,500 feet mean sea level (msl). During the time flight-following services were provided, communications were routine. The pilots did not communicate any difficulties or anomalies prior to the accident. The FAA was notified that the flight was overdue about 0016 on October 24th. An Alert Notice was issued at 0146 when initial attempts to locate the airplane were unsuccessful. The airplane was subsequently located about 1810 that evening after a search by local authorities and the Civil Air Patrol. FAA radar track data indicated that the flight departed STP and proceeded on course toward GFK. The initial radar data point was recorded at 2117:21 (HHMM:SS), with a Mode-C transponder altitude of 900 feet. According to the track data, the airplane climbed to a cruise altitude of 4,500 feet and was established on a course to GFK. About 2155 when flight-following was terminated, the flight changed from the assigned discrete transponder beacon code to a 1200 VFR transponder code. Based on VFR transponder returns correlated to the accident airplane, the flight remained within radar coverage until 2203:24 when it left the normal radar coverage area. It was approximately 2 miles west of Little Falls, Minnesota, at 4,600 feet at that time. No further radar data was recorded related to the accident flight. The accident site was located 16.5 miles northwest of the final radar data point. PERSONNEL INFORMATION The pilot was enrolled in the Commercial/Instrument Pilot Airplane training program at the University of North Dakota – Grand Forks. A university flight instructor accompanied the pilot on the night cross-country flight. The flight instructor was a former student of the university flight program. The flight instructor, age 22, held a Commercial Pilot certificate with single and multi-engine land airplane, and instrument airplane ratings. She held a Flight Instructor certificate with single and multi-engine airplane, and instrument airplane ratings. She was issued a Second-Class Airman Medical certificate on July 27, 2007. The medical certificate included a limitation that corrective lenses be worn. A review of the flight instructor’s logbook revealed that her most recent logged flight was dated October 1, 2007. University records indicated 9 additional flights between October 1st and October 23rd. According to the logbook and university records, the flight instructor had accumulated 647.1 hours total flight time, with 128.8 hours in multi-engine airplanes. Of that total, 80.4 hours were at night, 6.0 hours were in actual instrument conditions, and 56.0 hours were in simulated instrument conditions. She had accumulated at least 121.5 hours in Piper PA-44-180 (Seminole) airplanes. The pilot, age 20, held a Private Pilot certificate with a single-engine land airplane rating. He was issued a Second-Class Airman Medical certificate on July 27, 2007. The medical certificate was issued without limitations. According to university records, the pilot had accumulated 171.5 hours total flight time, with 13.0 hours in multi-engine airplanes. All of the multi-engine flight time was as dual instruction in a Piper PA-44-180. He had accumulated 18.4 hours of night and 50.9 hours of cross-country flight time. The records indicated that the pilot had 37.6 hours of instrument flight time. In addition, the pilot had acquired 10.7 hours of time in a multi-engine flight-training device. Of that total, 5.8 hours were on instrument flight procedures. The two flights prior to the accident flight (GFK to GAF, and GAF to STP) and the accident flight totaled approximately 2.8 hours of additional flight time. This was split with about 1.2 hours under day/dusk lighting conditions and 1.6 hours of night conditions. AIRCRAFT INFORMATION The accident airplane was a 2003 Piper PA-44-180 Seminole, serial number 4496174, certificated by the FAA under Type Certificate A19SO. The airplane was a four-place, low-wing, T-tail design, with a retractable, tricycle landing gear configuration. A cockpit/cabin door was located on the right side of the airplane adjacent to the forward passenger’s seat. The left side window adjacent to the pilot’s seat could be separated from the airframe for use as an emergency exit. The airplane was powered by two wing-mounted reciprocating engines. The left engine was a Lycoming O-360-A1H6, serial number L-39103-36A. The right engine was a Lycoming LO-360-A1H6, serial number L-769-71A. They were four-cylinder, normally aspirated, carbureted engines, capable of developing 180 horsepower each. The airplane was equipped with Hartzell HC-C2YR-2CEUF, serial number AU10422B, and HC-C2YR-2CLEUF, serial number AU11265B, adjustable pitch, constant speed propellers. The accident airplane was issued a normal category, standard airworthiness certificate on June 30, 2003. The airplane was subsequently purchased by the University of North Dakota on July 15, 2003, and registered as N327ND. It was placed on an experimental airworthiness certificate on September 7, 2005, for research and development purposes. The airplane was equipped with the Avidyne Entegra avionics suite, to include a Primary Flight Display and Multifunction Flight Display. The airplane was returned to a normal category, standard airworthiness certificate on June 13, 2006. The airplane was maintained under the University of North Dakota Progressive Inspection Program. Review of the maintenance records indicated that the most recent progressive inspection was a Phase 2 procedure, which was completed on October 1, 2007. The airframe had accumulated 1,801.6 hours total flight time as of that inspection. A Phase 1 inspection was completed on September 10, 2007, at 1,740.0 hours total airframe time. According to the university personnel, the airplane experienced a bird strike event the day prior to the accident. Damage was limited to the left engine. Maintenance records indicated that the left engine mufflers, both forward and aft, were subsequently replaced the morning of the accident. The airframe had accumulated 1,849.7 hours total flight time at the time of the maintenance work. METEOROLOGICAL INFORMATION The National Weather Service (NWS) Surface Analysis Chart and Weather Depiction Chart indicated Visual Flight Rules (VFR) conditions along the route of flight from STP to GFK, with generally clear skies and sustained north-northwesterly winds at 10 to 15 knots. VFR conditions are defined as cloud ceilings greater than 3,000 feet above ground level (agl) and visibilities greater than 5 miles. In addition, satellite imagery depicted clear skies over the site about the time of the accident. The closest weather reporting facility to the accident site was Staples Municipal Airport (KSAZ), Staples, Minnesota, located approximately 14 miles north-northwest of the accident site at an elevation of 1,287 feet msl. The airport was equipped with an Automated Weather Observation System (AWOS-3) and reported the following conditions surrounding the time of the accident. At 2155, winds from 340 degrees at 13 knots, gusting to 19 knots, visibility 10 miles, clear skies, temperature 8 degrees Celsius, dew point 2 degrees Celsius, and altimeter 30.11 inches of mercury. At 2215, winds from 340 degrees at 13 knots, visibility 10 miles, clear skies, temperature 7 degrees Celsius, dew point 2 degrees Celsius, and altimeter 30.12 inches of mercury. At 2237, winds from 350 degrees at 9 knots, visibility 10 miles, clear skies, temperature 7 degrees C, dew point 2 degrees C, altimeter 30.13 inches of mercury. The next closest weather reporting facility to the accident site was from Little Falls/Morrison County Airport – Lindberg Field (KLXL), Little Falls, Minnesota, located approximately 18 miles southeast of the accident site at an elevation of 1,122 feet msl. The airport was equipped with an AWOS-3 system and reported the following weather conditions surrounding the time of the accident: At 2155, wind from 300 degrees at 4 knots, visibility 10 miles, clear skies, temperature 6 degrees C, dew point 0 degrees C, altimeter 30.09 inches of mercury. At 2215, winds from 320 degrees at 6 knots, visibility 10 miles, clear skies, temperature 7 degrees C, dew point temperature 0 degrees C, altimeter 30.09 inches of mercury. At 2235, winds from 330 degrees at 11 knots, gusting to 17 knots, visibility 10 miles, clear skies, temperature 7 degrees C, dew point temperature 0 degrees C, altimeter 30.10 inches of mercury. An Airman’s Meteorological Advisory (AIRMET) for turbulence (AIRMET Tango Update 3) was issued at 1545 and was valid until 2200. The advisory warned of the possibility of moderate turbulence below 8,000 feet. The accident site was located within the boundaries of the advisory. At 2145, AIRMET Tango was re-issued and was valid until 0400 the following morning. The advisory noted the possibility of moderate turbulence below 15,000 feet. The accident site was located within the boundary of the advisory. There were no Severe Weather Forecast Alerts, Significant Meteorological Advisories (SIGMETs), Convective SIGMETs, or Center Weather Advisories applicable to the accident flight. Several pilot reports (PIREPs) noting turbulence across the region were on file. Between 1500 and 0100, fourteen PIREPs were filed – nine of them noted the presence of turbulence or low-level wind shear below 10,000 feet. At 1701, a report for moderate-to-severe turbulence between 4,000 feet and 6,000 feet in the vicinity of Minneapolis, southeast of the accident site, was filed. However, at 1946, a PIREP from a pilot in the vicinity of Marshall, Minnesota, noted negative turbulence between 4,000 feet and 9,000 feet. Sunset was at 1820 on the day of the accident, and civil twilight ended at 1950. The moon rose at 1639, and was approximately 45.6 degrees above the horizon at the time of the accident. About 98-percent of the moon’s visible disk was illuminated. WRECKAGE AND IMPACT INFORMATION The accident site was located in a sparsely populated, rural area northeast of Browerville, Minnesota. The airplane came to rest inverted in a shallow bog, about 15 to 20 feet deep. A portion of the tail of the airplane, including the lower rudder was visible above the water. The remainder of the airplane was submerged. The airplane was recovered to a hangar at the Little Falls-Morrison County Airport where a post accident examination was performed. The aircraft was recovered as a single unit; however, the aft fuselage was dislocated tail downward relative to the cabin area and wings. In addition, the upper portion of the nose separated from the airframe and was not recovered from the bog. The aft fuselage and empennage were separated from the forward fuselage to facilitate recovery. The lower portion of the nose structure was also separated from the fuselage in order to facilitate recovery. At the time of the post accident examination, the airplane structural components consisted of the nose; wings and center cabin, with the cockpit floor and instrument panel; and the aft fuselage and empennage, with the cockpit/cabin roof still attached. The nose section was separated from the airframe. The upper, hinged fiberglass nose cone was separated from the lower nose aluminum structure. The nose cone was not recovered from the bog. The nose landing gear remained attached to the trunnion fittings. The strut and wheel assemblies appeared intact. The cabin heater exhibited damage consistent with impact forces. The burner can was intact with the exception of weld fractures adjacent to deformed areas. No anomalies consistent with a pre-impact malfunction were observed. The cockpit floor was bent downward approximately 90 degrees near the leading edge of the wings. The cabin floor area and wing carry-through spars were intact. The pilot and passenger seats remained secured to the seat tracks. The instrument panel and flight controls remained attached to the floor structure. Damage to the cockpit flight and engine controls was consistent with impact forces. Flight control continuity was confirmed from the cockpit to the ailerons and the fuselage separation point at the aft cabin. Engine control continuity was confirmed from the throttle pedestal to the wing engine mounts. The fuel system exhibited continuity throughout the system. The fuel selectors were in the ON position when observed during the post accident examination. The left and right engine electric fuel pumps operated when energized, with no anomalies. The wings remained attached to the center cabin structure. Both wings were twisted leading edge down approximately 30 degrees along the entire span. The upper skins were deformed downward against the internal structure of the wings. The location of the spars and ribs were evident due to the skin deformation. The leading edge upper skin between the fuselage and the engine nacelles was deformed downward to the extent that it had torn through. The upper and lower wing skins were also torn through along the outboard sides of the engine nacelles. The left upper wing skin immediately inboard of the wing tip exhibited a crescent-shaped depression forward of the spar. The upper wing skin was torn through along the aft edge of this depression, adjacent to the spar. (A

Probable Cause and Findings

An in-flight collision with at least one Canada goose, and the resulting damage to the left stabilator that caused the airplane to become uncontrollable. Contributing to the accident was the night lighting condition, which precluded any possibility of the flight crew seeing the bird(s) prior to impact.

 

Source: NTSB Aviation Accident Database

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