Accident Case Study: High Aspirations

foreign [Music] [Music] on a hot summer afternoon July 25th 2020 the pilot of November 7677 Charlie a normally aspirated Piper pa-32 Cherokee Lance gets ready to depart South Valley Regional Airport a small non-towered airport just Southwest of Salt Lake City Utah South Valley Regional is located about 10 nautical miles south of Salt Lake City International Airport below Salt Lake City's class Bravo airspace floor and just about a mile and a half outside the airspace inner core which extends from the surface to 12 000 feet MSL the pilot recently obtained his instrument rating and he has filed an instrument flight plan for the cross-country flight South to Page Arizona he then plans to conduct a sightseeing flight over the Grand Canyon he's looking forward to offering his passengers an aerial view of the canyon a treat that will cap his family's Utah vacation at around 12 30 the FBO receives a call to top off the airplane with fuel about half an hour later between 1 10 and 1 20 PM the pilot and passengers arrive at the airport and a security camera captures them as they reach the airplane the video appears to show the pilot performing a pre-flight inspection of the aircraft once the pilot and passengers board the plane the pilot starts the engine the automated weather observation at 1 15 PM shows clear skies 10 miles visibility and the wind at six knots with a wind direction of 150 degrees the temperature is 32 degrees Celsius or 90 degrees Fahrenheit the airport elevation at 4606 feet MSL measures a density altitude of 7292 feet MSL earlier that day the pilot and his wife talked about the planned flight and they discussed the weight and balance and the high temperature and high altitude he assured her that everything was fine and he asked her to sit up front to help him navigate over the Grand Canyon now with the PreFlight completed the pilot taxis to Runway 1-6 which has a hard surface and is 5862 feet long on board the airplane are the pilot and his wife and their two small children seated behind them a family friend and her 12 year old daughter have settled in the back of the plane just before 1 37 PM a second security camera located Midfield the airport captures November 7677 Charlie as it lifts off about 3 700 feet down the runway with 2162 feet of Runway remaining it shows the windsock With the Wind coming out of the North creating a Tailwind takeoff the airplane departs straight out to the South Southeast on a magnetic heading of about 170 degrees November 7677 Charlie begins a series of shallow climbs and descents then disappears from the video shortly thereafter about 75 seconds after takeoff the airplane reappears on the video as it descends at a steep angle crashing into a residential neighborhood followed by a large plume of black smoke the airplane strikes a tree and three structures before it comes to rest in a backyard [Music] the post-crash fire engulfs most of the airplane's Wings its cabin and a residence causing four fatal injuries two serious injuries and one minor injury the Pilot's Wife their toddler son and the family friend's daughter survive 17 minutes after the accident the automated weather for South Valley Regional Airport reported the wind as 320 degrees at seven knots and three zero zero degrees at 10 knots with 10 miles visibility clear skies and the temperature at 32 degrees Celsius or 90 degrees Fahrenheit overall favorable weather conditions with a gentle to near moderate Breeze from the north however the density altitude at the airport elevation of 4606 feet MSL measured 7292 feet MSL this in combination with the Tailwind would certainly have impacted the airplane's ability to accelerate during the takeoff role and climb out that hot afternoon the airplanes wait at takeoff would have been about 3531 pounds according to the NTSB calculated weight and balance showed the center of gravity at 92.84 inches aft of datum the pilot operating handbook listed the maximum aft center of gravity as 95 inches and the maximum gross weight as 3 600 pounds precariously heavy for the high density altitude conditions review of performance charts indicated that the airplane should have been able to climb at a rate of around 500 feet per minute with the gear up based on the weight and environmental conditions at the time of takeoff however the surveillance camera video evidenced quite a different story that of an airplane having difficulty establishing climb performance this illustrates the sometimes Stark difference between book Numbers calculated by manufacturers and actual performance the typical Pilots can expect to achieve according to the flight instructors who had provided the Pilot's instrument Flight Training in the Lance the pilot handled the airplane without difficulty they recalled that the pilot had about 800 hours of flight time one of the instructors mentioned that the pilot was a conscientious responsible sort of guy and that he had no doubt in his ability to fly the airplane the designated pilot examiner who conducted the Pilot's instrument rating check ride mentioned that he did talk to the pilot quite a bit about pressure altitude and density altitude as he had missed one of those questions on his instrument written test and because he previously had made multiple cross-country flights to Utah he also discussed density altitudes effect on normally aspirated engines and how it can be a recipe for disaster in high density altitude conditions during a post-accided interview the Pilot's wife indicated that the pilot had taken the high temperature and high airport altitude into consideration she also said that he would meticulously do a full run-up including a propeller and flap check because it was a safety thing and for him it was something that he did every time the family friend's daughter said that before the flight the pilot asked about everyone's weight and that the bags were weighed in high density altitude conditions such as existed that afternoon the airplane may have seemed capable of takeoff even if well below the recommended AirSpeed due to reduced drag and ground effect this may have permitted the aircraft to become airborne but it wouldn't have been able to sustain flight out of ground effect according to the NTSB it is likely that after losing ground effect and while experiencing degraded climb performance due to the high density altitude the pilot responded by repeatedly pitching the nose down to gain air speed and then pitching the nose up to climb according to the NTSB data recovered from the engine data monitor showed that the pilot apparently manipulated the mixture lever to gain power but soon afterward the airplane exceeded its angle of attack engine data revealed that just after takeoff the exhaust gas temperatures of all cylinders increased rapidly and the fuel flow decreased five seconds later the exhaust gas temperatures for all cylinders decreased and the fuel flow increased fluctuations consistent with adjustments made to the mixture control the family friend's daughter mentioned that the pilot pulled a lever the flap handle between the pilot and co-pilot seats when they were still on the ground the first time the pilot tried to pull the lever it would not move then he tried it again and it started to move during the investigation the airplane manufactures representative observed the right flap in the 10 degree first Notch position consistent with that flap setting the left flap could not be inspected as it had been destroyed in its final report the NTSB determined that the pilot failed to maintain the airplane's speed during takeoff in high density altitude conditions and near the airplane's maximum gross weight the report concluded that the airplane exceeded its critical angle of attack which led to an aerodynamic stall loss of control and subsequent impact with structures and Terrain as the pilot of Cherokee November 7677 Charlie experienced high density altitude robs an airplane of power thrust lift and flight control effectiveness the thinner air results in longer takeoff and Landing distances and causes degraded climb performance that results in Shallow climb gradients the airplane was within Weight and Balance limits and near gross weight but the pilot could not seem to replicate performance numbers found in the pilot operating handbook perhaps it was technique perhaps it was the difference between test parameters and a real world operational situation the flight took off from Runway one six putting it on an almost direct course with the destination the winds out of the North were variable and close to a moderate Breeze in a high density altitude takeoff at nearly maximum gross weight such a Tailwind would certainly contribute to an even longer takeoff role and worse performance during the climb out did the pilot want to avoid the class Bravo airspace above the airport and to the North or was he misguided by the initial Asos report and didn't notice the wind direction had shifted from the south to the north before takeoff the flight took off during the afternoon Mountain flying guidance especially at airports exposed to high-density altitude conditions stresses taking off and landing in the early morning hours during cool temperatures that temper the ill effects of high density altitude in addition it's essential to reduce weight as much as possible to help alleviate sluggish aircraft performance in high density altitude conditions the pilot had previously made multiple cross-country flights to Utah perhaps those multiple successful flight routines bolstered his confidence in the Cherokee's performance during high density altitude conditions and as a result he overestimated the airplane's capabilities according to the Pilot's Wife and the flight instructors Who provided his instrument training and check ride the pilot was a conscientious person who took his flying seriously about seven months before the accident he had also received a high performance and complex endorsement and he eagerly looked forward to enjoying his certificate this accident had a devastating impact on many lives the pilot his family their friends and a person who perished in her house others affected by this tragedy are the close community of neighbors who came together to try and save the lives of those impacted by the disaster high density altitude and its effect on airplanes with normally aspirated engines is critical for us to understand as this accident illustrates significantly degraded aircraft performance can catch us off guard at precisely the most important time during our takeoffs and Landings performance data found in the pilot operating handbook can also mislead us this is why the aopa air safety Institute recommends padding performance numbers by 50 percent to account for differences between the manufacturer's published numbers and what we can expect in actual operational conditions attempting a takeoff close to gross weight at a high altitude in high temperatures and with an unfavorable Tailwind has serious implications sadly in this case the decision to take off under those circumstances ended in disaster thank you [Music] foreign [Music]

Channel: Air Safety Institute

Views: 260,700

Keywords: institute, aopa, aviation, pilot, fly, flying, flight, plane, airplane, airport, air, safety, asi, air safety, training, aircraft, owners, pilots

Id: sTo4GGRExGE

Length: 14min 15sec (855 seconds)

Published: Thu Aug 24 2023