Arizona

The lineman who spoke with the pilot/owner of the accident airplane before its departure reported that the pilot stated that he and the flight instructor were going out to practice for about an hour. The flight instructor had given the pilot/owner his initial instruction in the airplane and flew with the pilot/owner regularly. The flight instructor had also given the pilot/owner about 58 hours of dual instruction in the accident airplane. The pilot/owner had accumulated about 51 hours of pilot-in-command time in the airplane make and model. It is likely that the pilot/owner was the pilot flying. Several witnesses reported observing the accident sequence. One witness reported seeing the airplane pull up into vertical flight, bank left, rotate nose down, and then impact the ground. One witness reported observing the airplane go from east to west, turn sharply, and then go north of the runway. He subsequently saw the airplane hit the ground. One witness, who was a pilot, stated that he observed the airplane enter a left bank and then a nose-down attitude of about 75 degrees at an altitude of about 300 feet above ground level, which was too low to recover. It is likely that the pilot was attempting a go-around and pitched up the airplane excessively and subsequently lost control, which resulted in the airplane impacting flat desert terrain about 100 feet north of the active runway at about the midfield point in a steep nose-down, left-wing-low attitude. The airplane was destroyed by postimpact forces and thermal damage. All components necessary for flight were accounted for at the accident site. A postaccident examination of the airframe and both engines revealed no anomalies that would have precluded normal operation. Additionally, an examination of both propellers revealed rotational scoring and twisting of the blades consistent with there being power during the impact sequence. No anomalies were noted with either propeller that would have precluded normal operation. Toxicological testing of the pilot was negative for drugs and alcohol. The flight instructor’s toxicology report revealed the presence of tetrahydrocannabinol (THC). Given the elevated levels of metabolite in the urine and kidney, the absence of quantifiable THC in the urine, and the low level of THC in the kidney and liver, it is likely that the flight instructor most recently used marijuana at least several hours before the accident. However, the effects of marijuana use on the flight instructor’s judgment and performance at the time of the accident could not be determined. A review of the flight instructor’s personal medical records indicated that he had a number of medical conditions that would have been grounds for denying his airman medical certificate. The ongoing treatment of his conditions with more than one sedating benzodiazepine, including oxazepam, simultaneously would also likely not have been allowed. However, none of the prescribed, actively sedating medications were found in the flight instructor’s tissues, and oxazepam was only found in the urine, which suggests that the flight instructor used the medication many hours and possibly several days before the accident. The toxicology findings indicate that the flight instructor likely did not experience any impairment from the benzodiazepine medication itself; however, the cognitive effects from the underlying mood disturbance could not be determined.

The pilot began flying the twin piston-engine airplane model for the cargo airline about 11 months before the accident. Although he had since upgraded to one of the airline’s twin turboprop airplane models, due to the airline’s logistical needs, the pilot was transferred back to the piston-engine model about 1 week before the accident. The flight originated at one of the airline’s outlying destination airports and was planned to stop at an interim destination to the southwest before continuing to the airline’s base as the final destination. The late afternoon departure meant that the flight would arrive at the interim destination about 10 minutes after sunset. That interim destination was situated in a sparsely populated geographic bowl just south of terrain that was significantly higher, and the ceilings there included multiple broken and overcast cloud layers near, or lower than, the surrounding terrain. Although not required by Federal Aviation Administration (FAA) regulations, the airline employed dedicated personnel who performed partial dispatch-like activities, such as providing relevant flight information, including weather, to the pilots. Before takeoff on the accident flight, the pilot conferred briefly with the dispatch personnel by telephone, and, with little discussion, they agreed that the flight would proceed under visual flight rules to the interim destination. Information available at the time indicated that the cloud cover almost certainly precluded access to the airport without an instrument approach; however, the airplane was not equipped to conduct the only available instrument approach procedure for that airport. Additionally, the pilot did not have in-flight access to any GPS or terrain mapping/database information to readily assist him in either locating the airport or remaining safely clear of the local terrain. Although the airplane was not being actively tracked or assisted by air traffic control (ATC) early in the flight, review of ground tracking radar data showed that the flight initially headed directly toward the interim destination but then began a series of turns, descents, and climbs. The airplane then disappeared from radar as the result of radar coverage floor limitations due to high terrain and radar antenna siting. The airplane reappeared on radar about 24 minutes after it disappeared and about 9 minutes after the FAA-defined beginning of night. Based on the flight track, it is likely that the pilot made a dedicated effort to access the airport, while concurrently remaining clear of the clouds and terrain, strictly by visual means. This task was made considerably more difficult and hazardous by attempting it in dusk conditions, and then darkness, instead of during daylight hours. About 15 minutes after the airplane reappeared on radar, when it was at an altitude of about 13,500 ft, the pilot contacted ATC and requested and was granted an instrument flight rules clearance to his final destination. About 3 minutes later, the controller cleared the flight to descend to 10,000 ft, and the airplane leveled off at that altitude about 6 minutes later. However, upon reaching 10,000 ft, the pilot requested a lower altitude to escape “heavy” upand down-drafts, but the controller was unable to comply because the ATC minimum vectoring altitude was 9,700 ft in that region. About 1 minute later, radar contact was lost. Shortly thereafter, the airplane impacted terrain in a steep nose-down attitude in a near-vertical trajectory. Although examination of the wreckage did not reveal any preimpact mechanical deficiencies that would have prevented normal operation and continued flight, the extent of the damage precluded, except on a macro scale, any determination of the preimpact integrity or functionality of any systems, subsystems, or components, including the ice protection systems, autopilot, and nose baggage door. Analysis of the radar data indicated that the airplane was above 10,000 ft for at least 41 minutes (possibly in two discontinuous periods) and above 12,000 ft (in two discontinuous periods) for at least 18 minutes. Although the airplane was reportedly equipped with supplemental oxygen, the investigation was unable to verify either its presence or its use by the pilot. Lack of supplemental oxygen at those altitudes for those periods could have contributed to a decrease in the pilot’s mental acuity and his ability to safely conduct the light. Analysis of air mass data revealed that mountain-wave activity and up- and downdrafts with vertical velocities of about 1,000 ft per minute (fpm) were present near the accident site and that the largest and most rapid transitions from up- to down-drafts occurred near the accident site, which was also supported by the airplane’s altitude data trace. The analysis also indicated that the last radar target from the airplane was located in a downdraft with a velocity of between 600 and 1,000 fpm. Other meteorological analysis indicated that the airplane encountered icing conditions, likely in the form of supercooled large droplets (SLD), several minutes before the accident. Aside from pilot reports from aircraft actually encountering SLD, no tools currently exist to detect airborne SLD. Further, the tools and processes to reliably forecast SLD do not exist. SLD is often associated with rapid ice accumulation, especially on portions of the airplane that are not served by ice protection systems. Airframe icing, whether due to accumulation rates or locations that exceed the airplane’s deicing system capabilities, mechanical failure, or the pilot’s failure to properly use the system, can impose significant adverse effects on airplane controllability and its ability to remain airborne. Because of the pilot’s recent transition from the Beechcraft BE-99, in which the pitot heat was always operating during flight, he may have forgotten that the accident airplane’s pitot heat procedures were different and that the pitot heat had to be manually activated when the airplane encountered the icing conditions. If the pitot heat is not operating in icing conditions, the airspeed information becomes unreliable and likely erroneous. Erroneous airspeed indications, particularly in night instrument meteorological conditions when the pilot has no outside references, could result in a loss of control. The investigation was unable to determine whether the pitot heat was operating during the final portion of the flight. The investigation was unable to determine whether the pilot used the autopilot during the last portion of the flight. If he was using the autopilot, it is possible that, at some point, he was forced to revert to flying the airplane manually due to the unit’s inability and to a corresponding Pilot’s Operating Handbook prohibition against using it to maintain altitude in the strong up- and downdrafts, which would increase the pilot’s workload. Another possibility is that the autopilot was unable to maintain altitude, and, instead of disconnecting it, the pilot overpowered it via the control wheel. If that occurred and the pilot overrode the autopilot for more than 3 seconds, the pitch autotrim system would have activated in the direction opposite the pilot’s input, and, when the pilot released the control wheel, the airplane could have been significantly out of trim, which could result in uncommanded pitch, altitude, and speed excursions and possible loss of control. Whether the pilot was hand-flying the airplane or was using the autopilot, the encounter with the strong up- and downdrafts and consequent altitude loss likely prompted the pilot to input corrective actions to regain the lost altitude, specifically increasing pitch and possibly power. Such corrections typically result in airspeed losses; those losses can sometimes be significant as a function of downdraft strength and the airplane’s climb capability. If that capability is compromised by the added weight, drag, and other adverse aerodynamic effects of ice, aerodynamic stall and a loss of control could result. Radar tracking data and ATC communications revealed that another, similar-model airplane flew a very similar track about 6 minutes behind the accident airplane, except that that other airplane was at 12,000 ft not 10,000 ft. The 10,000-ft ATC-mandated altitude placed the accident airplane closer to the underlying high terrain and into the clouds with the icing conditions and the strong vertical air movements. In contrast, the pilot of the second airplane reported that he was in and out of the cloud tops and did not report any weather-induced difficulties. The accident pilot did not have any efficient in-flight means for accurately determining the airborne meteorological conditions ahead, and the ATC controller did not advise him of any adverse conditions. Therefore, the pilot did not have any objective or immediate reason to refuse the ATC-assigned altitude of 10,000 ft. Ideally, based on both the AIRMET and the ambient temperatures, the pilot should have been aware of the likelihood of icing once he descended into clouds. That, particularly combined with his previously expressed lack of confidence in the airplane’s capability in icing conditions, could have prompted him to request either an interim stepdown altitude of 12,000 ft or an outright delay in a direct descent to 10,000 ft, but, for undetermined reasons, the pilot did not make any such request of ATC. Based on the available evidence, if the ATC controller had not descended the airplane to 10,000 ft when he did, either by delaying or by assigning an interim altitude of 12,000 ft, it is likely that the airplane would not have encountered the icing conditions and the strong up- and downdrafts. In addition, if the presence of SLD and/or strong up- and downdrafts had been known or explicitly forecast and then communicated to the pilot either via his weather briefing, his onboard equipment, or by ATC, it is likely that the pilot would have opted to avoid those phenomena to the maximum extent possible. The flight’s encounter with airframe icing and strong up-and downdrafts placed the pilot and airplane in an environment that either exacerbated or directly caused a situation that resulted in the loss of airplane control.

Several witnesses observed the airplane before and during its takeoff roll on the morning of the accident. One witness observed the airplane for the entire event and stated that the run-up of the engines sounded normal. During the takeoff roll, the acceleration of the airplane appeared a little slower but the engines continued to sound normal. Directional control was maintained, and at midfield, the airplane had still not rotated. As the airplane continued down the 5,132-foot-long runway, it did not appear to be accelerating, and, about 100 yards from the end of the runway, it appeared that it was not going to stop. The airplane maintained contact with the runway and turned slightly right before it overran the end of the runway. The airplane was subsequently destroyed by impact forces and a postaccident fire. The wreckage was located at the bottom of a deep gully off the end of the runway. Postaccident examination of the area at the end of the runway revealed two distinct tire tracks, both of which crossed the asphalt and dirt overrun of 175 feet. A review of the airplane's weight and balance and performance data revealed that it was within its maximum gross takeoff weight and center of gravity limits. At the time of the accident, the density altitude was calculated to be 7,100 feet; the airport's elevation is 4,830 feet. For the weight of the airplane and density altitude at the time of the accident, it should have lifted off 2,805 feet down the runway; the distance to accelerate to takeoff speed and then to safely abort the takeoff and stop the airplane was calculated to be 4,900 feet. It is unknown whether the pilot completed performance calculations accounting for the density altitude. All flight control components were accounted for at the accident site. Although three witnesses indicated that the engines did not sound right at some point during the runup or takeoff, examination of the engine and airframe revealed no evidence of any preexisting mechanical malfunctions or failures that would have precluded normal operation. Propeller signatures were consistent with rotational forces being applied at the time of impact. No conclusive evidence was found to explain why the airplane did not rotate or why the pilot did not abort the takeoff once reaching the point to safely stop the airplane.

The aircraft was destroyed when it impacted terrain in the Superstition Mountains near Apache Junction, Arizona. The commercial pilot and the five passengers were fatally injured. The airplane was registered to Ponderosa Aviation, Inc. (PAI) and operated by PAI under the provisions of 14 Code of Federal Regulations (CFR) Part 91 as a personal flight. Night visual meteorological conditions (VMC) prevailed, and no flight plan was filed. The airplane had departed Falcon Field (FFZ), Mesa, Arizona, about 1825 and was destined for Safford Regional Airport (SAD), Safford, Arizona. PAI’s director of maintenance (DOM) and the director of operations (DO), who were co owners of PAI along with the president, conducted a personal flight from SAD to FFZ. The DO flew the leg from SAD to FFZ under visual flight rules (VFR) in night VMC. After arriving at FFZ and in preparation for the flight back to SAD, the DOM moved to the left front seat to act as the pilot flying. The airplane departed FFZ about 12 minutes after it arrived. According to a witness, engine start and taxi-out appeared normal. Review of the recorded communications between the pilot and the FFZ tower air traffic controllers revealed that when the pilot requested taxi clearance, he advised the ground controller that he was planning an "eastbound departure." The flight was cleared for takeoff on runway 4R, and the pilot was instructed to maintain runway heading until advised, due to an inbound aircraft. About 90 seconds later, when the airplane was about 1.1 miles from the departure end of the runway, the tower local controller issued a "right turn approved" advisory to the flight, which the pilot acknowledged. Radar data revealed that the airplane flew the runway heading for about 1.5 miles then began a right turn toward SAD and climbed through an altitude of about 2,600 feet mean sea level (msl). About 1828, after it momentarily climbed to an altitude of 4,700 feet, the airplane descended to an altitude of 4,500 feet, where it remained and tracked in an essentially straight line until it impacted the mountain. The last radar return was received at 1830:56 and was approximately coincident with the impact location. The impact location was near the top of a steep mountain that projected to over 5,000 feet msl. Witnesses reported seeing a fireball, and law enforcement helicopters were dispatched.

Following an uneventful flight, the flight crew briefed the arrival to the destination airport and set the calculated landing speeds. The captain and the first officer reported that during final approach, it felt like the airplane was “pushed up” as the wind shifted to a tailwind or updraft before landing near the runway number markings. Upon touchdown, the captain applied the brakes and thought that the initial braking was effective; however, he noticed the airplane was not slowing down. The captain applied maximum braking, and the airplane began to veer to the right; he was able to correct back to the runway centerline, but the airplane subsequently exited the departure end of the runway and traveled down a steep embankment. A pilot-rated passenger reported that throughout the approach to landing, he thought the airplane was high and thought that the excessive altitude continued through and into the base-to-final turn. He added that the bank angle of this turn seemed greater than 45 degrees. Recorded communication from the cockpit voice and data recorder (CVDR) revealed that during the approach to landing, the flight crew performed the landing checks, and the captain noted difficulty judging the approach. About 1 minute later, the recording revealed that the ground warning proximity system reported “five hundred” followed by a “sink rate, pull up” alert about 16 seconds later. Data from the CVDR revealed that about 23 seconds before weight-on-wheels was recorded, the airplane was at an indicated airspeed of about 124 knots and descending. The data showed that this approximate airspeed was maintained until about 3 seconds before weight-on-wheels. The recorded data further showed that the approach speed was set to 120 knots, and the landing reference speed (vREF) was set to 97 knots. Using the reported airplane configuration and the 3.5-knot headwind that was reported at the time of the approach and landing, calculations indicate that the vREF speed should have been about 101 knots indicated airspeed, which would have required a landing distance of about 3,112 feet. Utilizing the same airplane configuration and wind condition with the flight’s reported 124 knot indicated airspeed just before touchdown, the landing distance was calculated to be about 5,624 feet. The intended runway for landing was 5,132-feet long with a 1.9 percent downward slope gradient, and a 123-foot long overrun area. A postaccident examination of the airplane, including the braking system, revealed no evidence of mechanical malfunctions or failures that would have precluded normal operation. The pilot misjudged the airplane’s speed during the final approach, which resulted in runway overrun.

The captain initially flew the GPS (global positioning system) runway 2 approach down to minimums and executed a missed approach. The approach chart listed the minimum visibility for the straight-in approach as 1 mile, the minimum descent altitude (MDA) as 6,860 feet mean sea level (329 feet above ground level), and the missed approach point as the runway threshold. The audio information extracted from the CVR indicated the flight crew listened to the automated weather station at the airport twice during the second approach; both times the report stated, in part, "visibility one half [mile] light snow sky conditions ceiling two hundred broken one thousand overcast." At 0744:09, the first officer said, "there's MDA," and at 0744:27, "there's the runway right below ya." The CVR recorded the ground proximity warning system (GPWS) audio alert "sink rate, sink rate, sink rate, sink rate" at 0744:37, the sound of touchdown at 0744:52, and the sound of impact at 0745:00. According to both pilots, the airplane touched down even with the midfield windsock. The captain applied brakes and full reverse on both propellers; however, the airplane did not slow down and continued off the end of the runway, impacted and knocked down a chain link fence, and continued into downsloping rough terrain. The landing gear collapsed and the airplane slid to a stop. The operator reported that there was 2 to 3 inches of slush on the runway. The runway was equipped with pilot activated medium intensity runway lights, runway end identifier lights, and a visual approach slope indicator. The first officer said that on both approaches, he attempted to turn on the lights, but the lights did not activate. The Federal Aviation Regulation that specifies the instrument flight rules for takeoff and landing states, in part, that no pilot may operate an aircraft below the authorized MDA unless (1) the aircraft is continuously in a position from which a descent to a landing on the intended runway can be made at a normal rate of descent using normal maneuvers, and (2) the flight visibility is not less than the visibility prescribed in the standard instrument approach being used. The regulation further states that if these conditions are not met when the aircraft is being operated below the MDA or upon arrival at the missed approach point, the pilot shall immediately execute an appropriate missed approach procedure. In this case, the minimum required visibility was 1 mile versus the 1/2- mile visibility reported by the automated weather station. Additionally, the activation of the GPWS "sink rate" audio alert indicates a normal rate of descent was exceeded during the landing. Both of these conditions should have prompted the flight crew to execute a missed approach, which would have prevented the accident.

While on downwind the airplane experienced a loss of engine power and collided with houses and other obstacles during a forced landing on a residential neighborhood street. The pilot stated that he took off to troubleshoot a landing gear anomaly. He departed the airport area to the south. He cycled the landing gear and upon getting questionable indications in the cockpit of gear position he requested another aircraft confirm his landing gear configuration. Once he got the confirmation that all three wheels were down he proceeded back to the airport. About 2 miles away and approximately 1,800 feet agl the right engine began to lose power. He troubleshot the engine by attempting a restart, cycling the fuel pump off then on, and selected the right auxiliary fuel tank. The right engine did regain some power. He had lost some altitude during the process of troubleshooting the engine. He raised the landing gear to reduce drag, and entered right hand traffic for runway 17. At this point the left engine lost power, the airplane turned left, and he entered a descent to help maintain airspeed. He put the left propeller in feather, and switched to a new fuel tank, but the engine did not regain power. He did not have any altitude to exchange for airspeed and steered the airplane towards a clear residential street. The airplane impacted the roofs of at least two houses before colliding with the street. The pilot egressed through the rear of the airplane. An FAA inspector that examined the airplane wreckage stated that there was very little evidence of fuel onboard the airplane. The pilot stated that the left engine had failed due to fuel starvation and that he had fuel onboard but it was not in the right places.

The pilot of a MiG 21 and the pilot of a Piper PA-42 Cheyenne III met just prior to the flight to discuss the flight in which the Cheyenne pilot would be taking aerial photos of the MiG. The two pilots established a minimum altitude of 2,500 to 3,000 feet agl and 200 knots as their minimum airspeed. The pilots did not establish a minimum separation distance, as it was not intended to be a formation flight. The MiG pilot reported that after takeoff the aircraft experienced a problem with the landing gear retraction. The pilot recycled the landing gear and a successful gear retraction was indicated. The MiG pilot notified the Cheyenne pilot of the situation and the Cheyenne pilot indicated that they would join up with the MiG, look it over and check-out the landing gear, and let the MiG pilot know what they saw. The MiG pilot flew at 9,000 feet msl in a 30-degree right hand turn at 200 knots (about 90 percent power set) with approach flaps selected (approximately 25 degrees) until the Cheyenne met up with the MiG. The MiG pilot reported that he observed the Cheyenne meet up with him at his 5 o'clock position about 300-400 feet behind him and about the same altitude. In this position, the Cheyenne was in the direct path of the high velocity jet core exhaust from the MiG. The MiG pilot looked forward and when he looked back, he could not see the Cheyenne. The Cheyenne pilot then contacted the MiG pilot and made a comment about the right landing gear or gear door, but the statement was not completed. The MiG pilot did not hear back from the Cheyenne pilot. The MiG pilot then observed smoke rising from the desert terrain and notified air traffic control. The airport manager that was monitoring the conversation between the two aircraft stated that he heard the Cheyenne pilot indicate that he would "drop down and go underneath and let you know how it looks." Wreckage documentation noted that the main wreckage was located in an inverted position on flat terrain. The T-tail, which consisted of the upper half of the vertical stabilizer, horizontal stabilizer, and elevator had separated in flight and was located about 1/2 mile south of the main wreckage. Inspection of the upper portion of the aft vertical spar displayed a right bend and twist at the point of separation. No evidence of pre-existing cracks, corrosion or wear was noted to the material. Inspection of the MiG aircraft found no evidence of contact between the two aircraft.

The airplane impacted a road and scrub brush during a forced landing, which was preceded by a total loss of engine power. According to the pilot, he heard a loud "thunk" during takeoff climb and noted a loss of engine power. He manipulated the power lever from the full forward position to the full aft position ("stop-to-stop") and noted he had no power. Post-accident examination of the Pratt & Whitney Canada PT6A -114A engine revealed that the compressor turbine (CT) vane's outer rim liberated a section of metal that damaged the turbine blades downstream. The area of liberated material from the CT vane outer rim was examined by the manufacturer's metallurgists. The fracture surface of the outer rim showed evidence of fatigue with signs of oxidation in some areas indicating the crack had been in existence for some time. The liberated material impact damaged the CT blades and resulted in a loss of power. Review of the operator's records revealed that the engine was approved for an extension beyond the normally recommended 3,600-hour overhaul period, to 5,100 hours. The engine had accumulated 4,461.3 hours at the time of the accident. In addition, the turbine section (hot section) had a recommended overhaul period of 1,800 hours; however, the operator instead elected to utilize an engine trend monitoring program in accordance with a manufacturer issued service bulletin. Many errors were noted with the operator's manually recorded data utilized for the trend monitoring. However, it is not likely that the engine trend data, even had it been correctly recorded and monitored, would have depicted the fatigue cracking in the CT vane outer rim. As a result, the manufacturer issued a service information letter (SIL) PT6A116 in January 27, 2003 (following a similar investigation), which reminded operators to conduct borescope inspections of the CT vane during routine fuel nozzle maintenance, as the manufacturer's maintenance manual recommended. Review of the maintenance record entries for the accident engine revealed no evidence that a borescope inspection had been conducted in conjunction with the fuel nozzle checks.

The airplane descended to ground impact while maneuvering during a go-around. The pilot was meeting friends at the airport. The friends and their pilot arrived first, and were waiting at the departure end of runway 03. The airplane approached on a straight-in to runway 03. They thought that everything looked good on the approach. Due to a hump in the runway, they lost sight of the airplane just before it would have touched down. They then saw the airplane climbing back up on a go-around. As the airplane came abeam of their position, they saw it enter a steep banked left turn at an angle of bank they estimated between 60 and 80 degrees. At this point the landing gear was still down and the altitude was 200 feet above the ground. The witnesses saw the airplane's nose suddenly drop and the airplane then descended rapidly to the ground. No evidence of a preimpact mechanical malfunction or failure was found during detailed examination of the airframe systems and engines.