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On September 9, 2009, about 0945 mountain standard time, a Cessna 152, N94741, and a Piper PA-18-161, N994T, collided about 4,500 feet mean sea level (MSL) while located about one-half mile east of Coolidge, Arizona. Neither the flight instructor nor his dual student in the PA-28-161 were injured, but one of the private pilots in the Cessna 152 received serious injuries, and the second private pilot in the Cessna 152 was killed during the accident sequence. The Cessna 152, which was operated by Air Safety Flight Academy (ASFA), was substantially damaged by the mid-air collision and the subsequent ground impact. The Piper PA-28-161, which was operated by Oxford Airline Training Center, sustained substantial damage as a result of the mid-air collision and an off-airport power-out forced landing. At the time of the accident, the Piper PA-28 was in the process of entering the holding pattern associated with the GPS approach to runway 23 at Casa Grande Airport, Casa Grande, Arizona, and the Cessna 152 was in an en route climb after departing Coolidge Municipal Airport, Coolidge, Arizona. The Cessna 152 flight originated at Glendale Municipal airport, Glendale, Arizona, about 0700. The PA-28 flight originated at Goodyear Airport, Goodyear, Arizona, at 0830. Both airplanes were operating under the provisions of 14 Code of Federal Regulations, Part 91, and both airplanes were in visual meteorological conditions. Neither flight crew had filed a Federal Aviation Administration (FAA) flight plan.
According to the pilots in the PA-28, after departing Goodyear Airport, they proceeded to the Stanfield VOR (VHF Omni-directional Radio Range), where the dual student practiced holding before shooting two ILS (Instrument Landing System) approaches to Runway 05 at Casa Grande, Arizona (KCGZ). After the second ILS approach, the student executed a touch and go landing on Runway 05, and then after entering the Runway 05 upwind, announced on the KCGZ Common Traffic Advisory Frequency (CTAF) that they were on the upwind and would be tracking outbound to AYZUT (the initial approach fix (IAF) for the Global Positioning System (GPS) approach to runway 23 at Casa Grande). While passing through about 500 feet above ground level (agl), the crew of the PA-28 made another call on the KCGZ CTAF frequency, stating that they would be climbing to 4,500 feet to enter the hold at AYZUT. About that time, they also entered the frequency for the Arizona Fight Training Workgroup's (AFTW's) southeast practice area (122.85) in their number 2 communications radio. [Note: Both airplanes were operated by flight schools that are voluntary participants in AFTW. Among other things, AFTW provides an on-line Phoenix Area Terminal Area Chart that depicts AFTW-defined practice areas, within which the airplanes of participants transmit, receive, and monitor activity on specific AFTW designated frequencies (see aftw.org).] As they passed through 3,500 feet, the dual student made a call on the KCGZ CTAF, stating that they would be entering the hold at AYZUT in about one minute and thirty seconds. He then repeated that same call on the southwest practice area frequency. Upon reaching 4,500 feet, the dual student again transmitted on the KCGZ CTAF that he would be entering the hold at AYZUT. When the airplane was about 30 seconds from the IAF, the dual student made another call on the KCGZ CTAF, stating that he would be entering the hold in 30 seconds. Reportedly, up to that point in time, the crew of the PA-28 had heard a few other airplanes make calls on the KCGZ CTAF, but the advisory calls from these other airplanes indicated that their activities did not involve the area near the holding pattern at AYZUT or the inbound GPS approach course to Runway 23 at Casa Grande. The two crew members also heard a few calls from airplanes on the southeast practice area frequency, but all of those airplanes were near Phoenix-Mesa Gateway Airport (KIWA), which is located about 25 statute miles north-northwest of AYZUT. After reaching AYZUT at 4,500 feet, the dual student turned to a heading of 078 degrees to execute a parallel entry into the holding pattern, which had an inbound course of 258 degrees, and then made a call on the KCGZ CTAF to announce that he was entering the hold. The dual student then flew on the heading of 078 degrees for one minute, during which time neither he nor the CFI heard any calls on the southeast practice area frequency. He then turned right to a heading of about 288 degrees to intercept the inbound course. The dual student then transmitted on the KCGZ CTAF that he was "procedure turn inbound," for the GPS Runway 23 approach. Within what the occupants thought was about 10 to 15 seconds after rolling out on the intercept heading of 288 degrees; they both felt a sudden impact, followed immediately by the cessation of the rotation of the airplane's propeller.
Immediately after the impact, the airplane lost approximately 1,000 feet, in what was estimated by the occupants to be about three to four seconds. At that point in time, the CFI took control of the airplane and looked for a field in which to perform a power-off forced landing. The CFI selected a field, and as he maneuvered toward it, the dual student made emergency radio calls; first on KCGZ CTAF, then on the VHF emergency frequency of 121.5, then on 120.1 ( the tower frequency at Phoenix-Goodyear Airport; their home base), and then on the Phoenix Approach Control frequency for the area they were in (123.7). As the CFI approached the field, he slipped the airplane in order to lose more altitude without increasing his airspeed. Almost immediately after the airplane touched down, its left main gear separated from the airframe, and the airplane slid/rolled to a stop.
According to both occupants, from the time they departed Casa Grande heading to AYZUT, until the moment of impact, neither of them heard any pilots announce that they were departing Coolidge Airport, or climbing to the north after having departed Coolidge Airport. Both occupants stated that neither one of them saw the Cessna 152 prior to the collision, nor at the time of the impact did they realize that there had been a collision between themselves and another airplane. It was only after the CFI took control of the airplane that the dual student, who had been wearing a vision restricting instrument training hood prior to the impact, saw what appeared to be part of another airplane sticking out of the left side of the cowling area of the PA-28.
According to a representative of Air Safety Flight Academy (ASFA), the two private pilots in the Cessna 152 were performing a dual-crew cross county flight in accordance with the ASFA FAR Part 61 Instrument Flight Training Syllabus. The lesson requirements called for the flight to depart Glendale Municipal Airport (KGEU), Glendale, Arizona, and to proceed to Marana Regional Airport KAVQ), Marana, Arizona, with the flying pilot sitting in the left seat. During the en route portion of the flight, the flying pilot was to operate the airplane in a simulated Instrument Flight Rules (IFR) mode, while wearing an instrument training vision restricting device (instrument hood). Upon arriving in Marana, the flying pilot was to park the airplane, shut the engine down, and then after making an external inspection, the pilots were to switch seats, and the other pilot would fly a simulated IFR leg back to Glendale Municipal Airport. During both legs of the flight, the non-flying pilot was to, "…look out for traffic and act as a safety pilot." The lesson did not authorize any touch-and-go or full-stop landings at any airports except the initial point of departure (Glendale Municipal) and the planned turnaround point (Marana Regional).
According to the surviving pilot, he flew the first leg of the flight, which terminated at Marana Regional Airport, from the left seat. After landing at Marana, he switched seats with the other pilot, who was to fly the return leg to Glendale Municipal Airport. For reasons that were unable to be determined during the post-accident interview process, while en route back to Glendale, the occupants of the Cessna 152 decided to proceed to Coolidge Municipal Airport, Coolidge, Arizona, in order to, "…do some touch-and-go's." After performing an undetermined number of touch-and-go landings to Runway 05 at Coolidge, about 0937 the left seat (flying) pilot began a climb-out that started to the northeast, and according to recorded radar data, then began a turn to the left while passing through about 2,000 feet. The pilot continued the turn to the left, and initially rolled out on a ground track of about 245 magnetic degrees. Then about one minute later, when the airplane was due north of Coolidge Municipal Airport, the pilot turned slightly back to the right to a ground track of about 265 magnetic degrees. The radar data showed that the pilot maintained the track of about 265 magnetic degrees, and continued to climb, until the two airplanes collided. The radar data indicated that during the climb, the pilot was maintaining a climb rate that averaged between 700 and 750 feet per minute.
During the collision sequence, the right wing of the 152 separated about two feet outboard of the lift strut attach fitting, and the aft portion of its fuselage separated at the second bulkhead forward of the leading edge of the horizontal stabilizer. The Cessna 152 then entered an uncontrolled descent, during which the pilot in the left seat was ejected from the airplane. The airplane eventually impacted a flat open dirt field in the inverted position. When the Cessna 152 came to rest, the non-flying pilot, who ultimately recovered from the injuries he sustained during the accident sequence, was still strapped in the right seat.
In a couple of post-accident interviews with the surviving pilot in the Cessna 152, he stated that the event had been a big shock, and that he could not clearly and accurately remember most of what went on. Because of his emotional condition, and because Chinese was his primary language, he asked for the interviews to be performed through an interpreter. Although the surviving pilot later wrote a brief statement, he was unable to answer many of the interview questions, and most of the ones that he could answer were responded to in a one word response. He said that he could not remember what radio calls he had made, nor at what location or point in time might those calls have been made. He believed that he had been monitoring and transmitting on the southeast practice area frequency, but he was not sure that was the case. He could not remember exactly what airspace he had been in, or what they were doing just prior to the accident; except that they were heading back to Glendale. He believed that he had been into Coolidge Municipal Airport before, but he could not remember if that was with an instructor or not. He could not remember exactly what altitude they were at when the collision took place, but believes it might have been around 4,000 feet. He said that he did remember the "strong hit" when the two airplanes collided, and he stated that he did not remember seeing the other airplane prior to the collision. The next thing he remembered after the impact of the collision was someone on the ground telling him he was going to be alright, as they cut his seatbelt in order to facilitate his extrication.
The occupants of the Piper PA-28 were a flight instructor and a student who held a private pilot rating. The 47 year old flight instructor held a commercial pilot certificate, with airplane single-engine land and airplane multiengine land ratings, and an instrument rating. He held an instructor rating for airplane single-engine, airplane multiengine, and instrument airplane. His last FAA airman's medical, as class 3 with limitations/waivers, was on December 1, 2008. Of his 2,081 hours of total flying time, 1,250 were in a Piper PA-28.
The 20 year old student, a British national, held a private pilot certificate, with airplane single-engine land, and airplane multiengine land ratings, as well as an instrument rating in airplanes. His last FAA airman's medical, a Class 1 with limitations/waivers, was on April 23, 2009. Of his 278 hours of total flying time, 228 were in a Piper PA-28.
The occupants of the Cessna 152, both of whom were Chinese nationals, were both private pilots. The 23 year old pilot in the right seat (the survivor) held an airplane single-engine land rating, and his last FAA airman's medical, a class 1 without limitations or waivers, was on October 6, 2008. Of his 156 hours of total flying time, 127 were in a Cessna 152.
The 27 year old pilot in the left seat (the fatality) held an airplane single-engine land rating, and his last FAA airman's medical, a class 1 without waivers or limitations, was on October 6, 2008. Of his 160 hours of total flying time, 100 were in the Cessna 152.
The 1988 Piper PA-28-161, N994T, serial number 2816037, was registered to, and operated by, Oxford Airline Training Center Incorporated. Its last inspection (AAIP) was completed on September 4, 2009.
The 1983 Cessna 152, N94741, serial number 15285778, was registered to Christiansen Aviation Incorporated, and operated by Air Safety Flight Academy. Its last inspection (100 hour) was completed on June 26, 2009.
Neither airplane had a Traffic Alert and Collision Avoidance System (TCAS) installed, and neither airplane was required to have such a system.
The 0930 aviation surface weather observation (METAR) recorded at Coolidge Municipal Airport, which is located about seven statute miles southeast of the collision site, indicated clear skies, calm winds, and a visibility of 10 miles. The skies had been clear, with 10 miles visibility, in the area around Coolidge since sunrise.
The 0953 METAR recorded at Casa Grande Airport, which is located about 16 miles west of the collision site, indicated clear skies, winds from 080 degrees, and a visibility of 10 miles.
Neither airplane was in contact with Phoenix Approach Control (TRACON), and according to the FAA, Phoenix Approach does not normally provide radar traffic advisories for training flights in the Casa Grande/Coolidge area. The reason that this coverage is not normally provided is due to both the very high volume of student activity, and the fact that members of AFTW have their own clearly defined and published system of making radio calls in the blind to report their position and their intentions.
The occupants of the PA-28 reported that they had been making radio calls on the Casa Grande CTAF in order to report both their position and their intentions. They also reported that after reaching 3,500 feet, they monitored the AFTW southeast practice area frequency, and made one call on that frequency to announce their intention to hold at AYZUT. This call was made about one minute and thirty seconds prior to entering holding. They also reported that they did not hear any transmissions from airplanes announcing their position as being in the area of north of Coolidge or near AYZUT.
According to the surviving pilot in the Cessna 152, due to the traumatic nature of the events that followed the collision between the two airplanes, including the impact with the ground after the uncontrolled descent, he did not have an exact recollection of the moments leading up to the event. He believes that they were monitoring and transmitting on the AFTW southeast practice area frequency, but he was not absolutely sure. He further stated that he always makes the calls on the radio that his instructor taught him to make, but he did not specifically remember what calls were made prior to the collision.
During the post accident inspection, the Garmin GNS 430 in the PA-28 indicated that the primary frequency was set on 120.1 (Phoenix -Goodyear Tower), and the back-up frequency was 121.5 (VHF emergency). The airplane's number 2 radio, a Bendix /King KX 155, was found in the off position at the accident site, and did not illuminate or function when power was applied during the initial post-accident inspection. It was later removed from the airplane and tested by an inspector from the FAA's Scottsdale Flight Standards District Office (FSDO), and although the radio broadcast and received normally, the frequency that it was set in it at the time of the accident was not positively determined.
The number one communication radio in the Cessna 152 was found set to a primary frequency of 122.85 (the AFTW southeast practice area frequency), with a back-up of 123.07 (Coolidge CTAF).
Because neither of the subject airplanes had cockpit voice recorders, and since neither the AFTW practice area frequencies or the CTAF for Casa Grande or Coolidge are recorded at a remote location, the NTSB has no way to positively determine what transmissions were or were not made by the occupants of either airplane.
WRECKAGE AND IMPACT INFORMATION
The Cessna 152 impacted the ground inverted in a flat open dirt field about 2,290 feet southeast (117 degrees magnetic) from the intersection of Main Street and East Coolidge Avenue in Coolidge. Except for the outboard portion of its right wing, which remained attached to the PA-28, and its tail section, which had separated in flight and landed about 500 feet southeast of the main wreckage, the Cessna 152 came to rest mostly intact. The fuselage, including all three landing gear, showed little damage, except for the shattering of the windshield and some crushing of the wing spar carry-through area over the top of the cockpit. The left wing, including its lift strut, showed little damage, except for some wrinkled top and bottom skin near its root, and the bending and wrinkling of the inboard one foot of the flap. The right wing had separated at the aft spar attach fitting, and the section between its root and the lift strut attach fitting was severely crushed, torn, and twisted. The right lift strut itself was bent about 70 degrees about midpoint of its length, and all that remained outboard of the lift strut attach fitting was about two feet of main wing spar and leading edge skin. The propeller blades, which showed no cord-wise scarring, remained mostly straight, except for about the outboard 12 inches of one blade, which was bent forward about 60 degrees, and the outboard 18 inches of the other blade, which was bent forward about 45 degrees.
Both seats were still on their tracks, and the seatbelts of both occupants were still buckled, with the shoulder strap attached. One side of the survivor's seatbelt had been cut by rescue personnel.
The PA-28 forced landing took place about one and three-quarter miles east (100 degrees magnetic) from where the Cessna 152 impacted the terrain. It touched down in a field of one-foot high commercially grown crops, and came to rest about 2,240 feet east (93 degrees magnetic) from the intersection of East Starview Avenue and North Nafziger Road. Except for the separation of the left main landing gear, the slight bending of the aft edge of the left aileron, and the collision impact damage to the left side of the engine compartment, the airframe of the PA-28 showed little damage.
After being recovered to the facilities of Air Transport, in Phoenix, Arizona, both airplanes underwent further examination. There it was determined that the right wing tip of the Cessna had broken through the aft portion of the lower left engine cowl of the Piper. It then became wedged in the area aft of the Piper's engine crankcase and the nose gear strut, and forward of the engine firewall. Approximately two feet of the wing structure was wedged within the engine compartment. Most of the rest of the separated wing structure, inboard to a location near the lift strut attach fitting, was sticking out horizontally from the Piper's engine compartment. When removed, it was seen that on the portion of the wing that had been wedged within the engine compartment, the forward portion had been crashed down and aft, and the aft portion had been crushed down and forward, with the midpoint being the wing false spar to which the aileron attaches. The portion of the wing that was sticking out into the airstream after separating from the Cessna was torn, twisted, and deformed.
The three landing gear of the PA-28 were inspected for any evidence of contact with the Cessna 152. There was no such evidence on the right main gear, and the only evidence on the nose landing gear was a vertical paint smear about four inches long along the left side of the strut fork. An inspection of the left gear revealed a number of abrasions, scratches and rub marks on the left (outside) wall of the tire. One of the scratches that ran along the sidewall of the tire ended in a cut/puncture that was about one and one-half inch long (see image 15). About one-half the circumference of the wheel showed evidence of freshly scrapped or chipped paint, and a section of about 60 degrees of the wheel's perimeter had been bent inward toward the tire sidewall.
A further inspection of the Cessna 152 revealed that the separated aft fuselage and empennage section had rubber smearing marks on its skin consistent with the Piper's left main gear tire making contact with the upper portion of the right side of the Cessna fuselage adjacent to the forward end of the Cessna's vertical stabilizer dorsal fin. The fuselage skin at that location was buckled up and aft, with the rubber smears being on the forward and down side of the skin buckles. The smearing then moved aft along the right side of the dorsal fin, terminating about halfway along the fin's length. Further rubber smearing began near the base of the vertical stabilizer forward end, with the forward edge of the stabilizer being forced aft enough to create a one-half inch separation between the forward edge of the stabilizer and the aft end of the vertical stabilizer fin. Aft of that location, the Cessna's right horizontal stabilizer had been forcefully crushed in and aft, with the elevator having completely separated. The skin and internal structure of the horizontal stabilizer was buckled and accordioned tightly up against the right side of the empennage, and clearly visible on the outward facing skin buckles of that structure and the lower side of the vertical stabilizer were two concentric circular scars. The outer scar, which was created by rubber smearing and had smooth rounded edges, was about six inches outward of the inner scar (see image 11). The inner scar, which had a much more defined angular edge, transferred small amounts of white paint onto the skin of the Cessna 152. When the left main gear wheel and tire of the Piper PA-28 was placed alongside this scar, it became clear that the inner scar matched the shape and size of the Piper left main wheel, and the outer scar matched the shape and size of the Piper left main tire.
MEDICAL AND PATHOLOGICAL INFORMATION
An autopsy was performed on the pilot of the Cessna 152 under the authorization of the Pinal County Medical Examiner's Office. That autopsy determined that the cause of death was multiple blunt force injuries, and that the manner of death was accidental.
In addition, the Federal Aviation Administration's Civil Aeromedical Institute (CAMI) performed a forensic toxicology examination on samples taken from the pilot of the Cessna 152. That toxicology was negative for carbon monoxide and cyanide in the blood, and negative for ethanol and drugs in the urine.
ADDITIONAL DATA AND INFORMATION
A review of the recorded radar data revealed that about 0944:15, as the PA-28 was just short of being half way through its right turn to enter the holding pattern, as it was passing through a southeasterly heading, the Cessna 152 was located about seven tenth of a mile away, and momentarily off the PA-28's nose, about 200 feet lower (4,300 feet). At that time, the PA-28 was about 60 degrees to the right of the nose of the climbing Cessna 152, about 200 feet higher (4,500 feet). About 0944:30, the Cessna 152 was climbing straight ahead through 4,400 feet, and was about two-tenth of a mile east of where it impacted the terrain after the collision. At 0944:20, the PA-28 was in a right turn while level at 4,500 feet, and about four-tenth of a mile north northeast of where the Cessna 152 impacted the terrain.