The Crash of Atlas Air Flight #3591
Atlas Air Flight #3591 Crash Executive Summary:
On February 23, 2019, 12:39 central standard time, Atlas Air flight #3591 (Atlas 3591) operating on behalf of Amazon Prime Air, Amazon.coms’ newly founded package delivery carrier, crashed into Trinity Bay in Baytown, Texas (TX); United States of America (U.S.A.)1. The aircraft was “destroyed and highly fragmented”1. Three fatal injuries were confirmed to be the two pilots operating the flight and one non-revenue jumpseat pilot1. The flight had originated from Miami International Airport (KMIA) in Florida; U.S.A. with a destination of George Bush Intercontinental Airport (KIAH) in Houston, Texas; U.S.A. Atlas 3591 was operating under United States (U.S.) Title 14 Code of Federal Regulations (C.F.R.) Part 121 as domestic cargo flight1. The aircraft was a Boeing 767-375 Boeing Converted Freighter (B.C.F. ), with a U.S. Federal Aviation Administration (F.A.A.) registration identification N1217A1. The aircraft was powered by two General Electric (G.E.) CF-6 engines and had accumulated 91,063 flight hours, inclusive of 23,316 cycles (flights), during its lifespan, since its production in 19921.
The Crash Event:
At approximately 12:39 Central Standard Time (C.S.T.) (local time)(all times are in 24-hour format) radar and radio contact with Atlas 3591 were lost and the F.A.A. issued an Alert Notice (AL.NOT.) for the aircraft3. At the time of communication loss, the aircraft was approximately 40 miles southeast of George Bush Intercontinental Airport (KIAH), Houston, Texas; U.S.A. Shortly after the AL.NOT. was issued, the U.S. National Transportation Safety Board (N.T.S.B.) “Go–team” of investigators were launched along with F.A.A. investigators into Trinity Bay in Baytown, TX (U.S.A.)1. At approximately 13:45 C.S.T. (local time), the F.A.A. and Chambers County Sheriff’s Office confirmed the aircraft had indeed crashed.
The aircraft was piloted by Captain Ricky Blakely and First Officer Conrad Jules Aska, both Atlas Air pilots. Onboard in the cockpit jumpseat, or rear observation seat, was Captain Sean Archuleta, a Mesa Airlines pilot, whom had recently accepted a pilot position as a First Officer with United Airlines. Sadly, all three were confirmed fatalities of the crash3.
Timeline of the Atlas 3591 Crash:
Atlas 3591 took off from Miami International Airport (KMIA) at 11:33 local time (16:33 UTC) enroute to Houston’s George Bush Intercontinental Airport (KIAH)2. Approximately 20 minutes later, the aircraft reached a cruise altitude of 40,000 feet Mean Sea Level (M.S.L.)2. After an uneventful cruise phase, the aircraft started its descent into Houston at 12:07 local time (18:07 Coordinated Universal Time [U.T.C.])2.
At approximately 12:30, the pilots contacted Houston Terminal Radar Approach Control (T.R.A.C.O.N.) to report their descent through 17,800 feet M.S.L. along with their intent to land on runway 26L at Houston’s George Bush Intercontinental Airport (KIAH)1. At 12:34, Houston approach informed Atlas 3591 that there was light to heavy precipitation in the vicinity of the planned approach. One minute later at 12:35, the pilots were passed to the T.R.A.C.O.N. final controller1. The Atlas 3591 pilots informed the controller that they had received the latest weather report via the Automatic Terminal Information System (A.T.I.S.)1. The T.R.A.C.O.N. controller then advised the Atlas 3591 pilots to expect to be vectored to runway 26L at KIAH and asked if they would like to be routed to the west or north of the band of “light to heavy” precipitation1. The Atlas 3591 pilots informed the T.R.A.C.O.N. controller that they would like to be routed to the west of the precipitation1. At this time, the aircraft was still descending normally through 12,000 feet M.S.L. and with a groundspeed of 290 knots1.
The T.R.A.C.O.N. controller advised the Atlas 3591 pilots that to avoid the “light to heavy” precipitation, an expedited descent to 3,000 M.S.L. was necessary1. At 12:37 the controller instructed the Atlas 3591 pilots to turn to heading 270 degrees1. Automatic dependent surveillance-broadcast (ADS-B) flight data shows that the aircraft did exactly that as it passed through 8,500 feet1. One minute later at 12:38 the controller informed the crew that they would be clear of the storms in approximately 18 miles and they could expect a turn to the north to set them up for a base leg to runway 26L at KIAH1. The Atlas 3591 pilots acknowledged, however at this point the radar data started to indicate problems.
The aircraft leveled out at 6,200 feet M.S.L. before reaching 6,300 feet M.S.L. in a “slight climb,” according to the ADS-B flight data1. The Flight Data Recorder (F.D.R.), which was recovered from the crash site, indicated vertical accelerations that were consistent with that of an aircraft penetrating turbulent air1. The F.D.R. data showed a sudden maximal engine thrust increase suddenly, resulting in an increased aircraft wing airfoil lift and subsequent four degree (approximately) aircraft nose pitch up1. Over the course of the next eighteen seconds, the aircraft pitched approximately 49-degrees nose-down1. The overall aircraft nose pitch-down was 53-degrees. “FDR, radar, and ADS-B data indicated that the airplane entered a rapid descent on a heading of 270-degrees, reaching an airspeed of about 430 knots”1. The pilot’s flight controller yoke stick shaker, a device that warns pilots of an imminent stall, did not activate1. In the final seconds of the descent, the aircraft reached a speed of about 430 knots (495 miles per hour) and pitched up 29-degrees, to about 20-degrees nose-down, during the final decent before impacting Trinity Bay in a wings level attitude1. Security camera footage was released that captured the impact and validated the F.D.R. data.
The Crash Investigation:
The N.T.S.B. immediately began their investigation into the crash using drones and airboats to survey the debris field since the location of the crash site is a marshy area. In addition, representatives from the F.A.A., Atlas Air, General Electric (G.E.) Aviation, Boeing, the International Brotherhood of Teamsters, National Air Traffic Controllers Association and the Texas Game Warden also arrived on site to assist investigators1. The full force of the F.A.A. and N.T.S.B. included all resources, including attainable resources, and expertise were intensely focused on crash, which included the major investigation divisions and specialists in structure, systems, powerplants, Air Traffic Control (A.T.C.), and meteorology, to name a few1. “Specialists in operations, human factors, maintenance records, and flight recorders supported the investigation from other locations”1. Numerous other federal, state, and local law enforcement and public safety agencies also assisted the crash investigation teams1.
The Atlas 3591 crash wreckage “main debris field was oriented east to west about 350 yards long by about 200 yards wide”1. “One engine and some landing gear components were found beyond the main debris field to the west”1. Light weight components and cargo from the Atlas 3591 wreckage floated southward and were recovered up to twenty miles away1. The wreckage laid in one to three feet of dark murky and swampy water that made the Atlas 3591 crash debris “very difficult”1. The muddy bottom of Trinity Bay did not provide a suitable foundation for heavy recovery equipment, thus airboats, barges, and amphibious equipment was brought in to search for the recorders and harvest aircraft wreckage debris1.
On March 1, the Cockpit Voice Recorder (C.V.R.) was recovered and transported to the N.T.S.B. laboratory in Washington D.C. The initial review of the C.V.R. was completed the next day (3-2-2019) by the engineers at the N.T.S.B. Office of Research and Engineering Vehicle Recorder Division4. More information on the N.T.S.B. Office of Research and Engineering can be found by clicking here. On March 3, the aircraft’s critical flight data recorder, or “Black Box”, was recovered by investigators. The audio recovered from the C.V.R. indicates the following4:
Images Source: N.T.B.S. Flickr website: https://www.flickr.com/photos/ntsb/sets/72157689995919483/
- The length of the recording is approximately two hours.
- The recording includes the final moments of the flight, but audio is poor.
- There are periods where the crew discussion content is hard to determine.
- The Atlas 3591 were in communication with air traffic control (A.T.C.) and were being provided radar vectors to runway 26L at George Bush Intercontinental Airport (KIAH) in Houston, Texas; U.S.A.
- “Crew communications consistent with a loss control of the aircraft began approximately 18 seconds prior to the end of the recording”.
The Flight Data Recorder (F.D.R.) arrived at the N.T.S.B. ’s Recorder Lab Sunday (3-3-2019) at 11:45 p.m.4. “The memory module was disassembled, cleaned and dried, and download of the data was achieved Monday afternoon”4. After examination of the flight data recorder data, investigators determined they had captured data approximately fifty-four hours of data including: the Atlas 3591 flight and from the seventeen prior flights of the aircraft4. Additionally, “There were approximately 350 parameters recorded by the FDR detailing the motion of the aircraft and operation of its engines, flight controls and other systems”4. The initial N.T.S.B. website posted press-release regarding the status of the C.V.R. and F.D.R. can be viewed by clicking here.
On March 12, 2019 the N.T.S.B. released an investigative update on the accident detailing the chain of events, as well as how the wreckage was situated1. Also, included in the update was detailed information about the aircraft and the crew. The current status of the N.T.S.B. investigation can be viewed by clicking here.
The Boeing 767 aircraft has been in operation since the 1970’s, according to Boeing7. “The Boeing 767, built in Everett, Wash., alongside the 747, can carry from 200 to 300-plus passengers”7. “In 1985, as the pioneer for ETOPS (for “Extended-range Twin-engine Operational Performance Standards”), the 767 was certified for extended flights that would make it the first commercial twin jet to fly regular routes across the Atlantic”7. “The 767-200 was first ordered in 1978, and the last was delivered in 1994”7. Boeing has recently delivered its 100th dedicated production Boeing 767-300 friegher and the model has accumulated over two million flight hours, according to Boeing8. The Boeing 767 has historically and actively been a mainstay in airline passenger transport oprations globally for decades. A crash of a Boeing 767 is an unusually rare event.
There has been no further information made public by the N.T.S.B. since the March 12, 2019 investigation update. Regardless, there is still much debate about what could have possibly caused Atlas 3591 to crash. At this stage of the investigation very few factors can be ruled out. The presence of thunderstorms in the vicinity has some wondering if severe turbulence might have contributed to the pilots losing control of the aircraft. However, aviation safety experts disagree with the theory and say there is no evidence to suggest it was a contributing factor in the crash. In fact, turbulence hasn’t been the cause of an accident involving a large airline and/or transport category aircraft since the 1960s5. It is also possible an undetected meteorological event like a major “Microburst” and/or series of Microbursts, which are very strong and persistent downward flows of air. Microbursts can be dangerous during the takeoff and landing phases of flight and have been adequately addressed by the F.A.A., N.T.S.B., and aircraft operators.
What is more intriguing to investigators is the engine surge that occurred in the final moments before the accident. The General Electric (G.E.) CF6 engines are well seasoned and battle tested with forty-five years of operational experience, according to General Electric (2019)6. “CF6 engines have compiled nearly 430 million flight hours since they first entered commercial revenue service in 1971,” according to General Electric (2019)6. Certified to power more than 13 different aircraft types, the CF6 has accumulated more than 115 million flight cycles in service,” according to General Electric (2019)6. The stability and reliability of the G.E. CF6 engines have been proven and demonstrated to any potential lay person reading this article that is reasonable. Why did both engines suddenly go to maximum power during a controlled descent, when there was no indication of a stall? Did one of the pilots accidently activate the Maximum Takeoff and Go Around (M.T.G.O.) button on the engine throttle controls or the forward flight panel? Did one of both of the pilots have a sudden medical emergency such as a seizure(s), stroke(s), heart attack(s), or and uncontrollable psychotic episode(s)? Data shows the aircraft was steady and stable at about 230 knots when the engines went to full power1,2,5. Whatever the cause, this anomaly is the first in the fatal chain of events, as aircraft crashes and incidents typically have a compounding chain of events. The second puzzling event troubling investigators is the downward deflection of the elevators that put the aircraft in a 49-degree nose-down attitude1,2,5. Was this event a response from the pilots following the engine surge? If so, why did the pilots react in such an extreme way? Was the a major problem and/or failure of the autopilot system and/or the elevator pitch trim system that physically decreases the mechanical force pilots need exert on the pilots control column? Did a hydraulics system failure associated with the elevator flight controls contribute to the loss of aircraft control? Remember, the data shows that the increased output of thrust resulted in the aircraft transitioning to a four-degree nose-up attitude1,2,5. That would certainly not warrant such a drastic response that resulted in a very unusual nose-down attitude. And third, what caused the aircraft to slowly pull up to the final attitude of 20 degrees nose-down prior to impact? Was the crew desperately trying to recover the aircraft after suffering a catastrophic systems failure?
Experts believe the dive was the result of several possibilities: a major mechanical or computer malfunction, pilot error, or a deliberate act5. Since the U.S. Federal Bureau of Investigation (F.B.I. ) is not involved at this point in the investigation, it is unlikely that this accident was an intentional act and/or an external criminal act(s). Personally, I believe this accident is likely the result of some sort of flight control or systems malfunction. It is conceivable that the elevator trim system went into a completely out of control, or “Rogue“, and the pilots of Atlas 3591 could not overcome the event. A complete loss of all hydraulic systems, including backup systems, could explain the initial 53-degree aircraft nose-down pitch event over eighteen seconds. However, this does not explain the 29-degree aircraft nose-up pitch prior Atlas 3591 impacting the ground. These conditions could explain the erratic changes in pitch and the pilot’s inability to recover the aircraft. What completely baffles me however, is the engine surge. Surges in jet engines are usually the result of internal failures, compressor stalls, pneumatic malfunctions, or bird strikes, the latter of which is a common occurrence. The possibility of both engines on a 767 suffering a compressor stall or internal failure at the same exact time seems very unlikely. Also, the N.T.S.B. has not indicated that the aircraft suffered a bird strike in any way, although it is a more likely scenario, given the altitude of the aircraft at the time of the surge.
In time, I’m confident the N.T.S.B. will definitively elucidate the exact cause(s) of this tragic Atlas 3591 crash. Until then, all you and I can do is wait for more information from investigators. In the meantime, I hope the families of the three men killed in this accident can somehow find their peace. It’s certainly a challenging time for them right now while they continue to wait for answers. It’s a troubling time for the aviation community as whole, in fact. Three Boeing aircraft have gone down in matter of months, and the company is certainly getting some unfavorable attention, to say the least. More of that to come, but for now let’s keep the families of victims in our minds, and hope that we receive answers to the tragedies we have witnessed lately.
- National Transportation Safety Board. (2019, March 12). Atlas Air #3591 crashed into Trinity Bay. Retrieved on June 13, 2019; from: https://www.ntsb.gov/investigations/Pages/DCA19MA086.aspx
- Ranter, H. (2019, February 23). ASN Aircraft accident Boeing 767-375ER (BCF) (WL) N1217A Trinity Bay, near Anahuac, TX. Retrieved on March 28, 2019; from: https://aviation-safety.net/database/record.php?id=20190223-0
- Aviation Tribune. (2019, March 17). Atlas Air Boeing 767 Operating for Amazon Prime Air Crashes. Retrieved on March 26, 2019; from: http://aviationtribune.com/safety/atlas-air-boeing-767-operating-for-amazon-prime-air-crashes/
- National Transportation Safety Board. (2019, March 5). NTSB Laboratory Completes Initial Review of Cockpit Voice Recorder, Recovers Flight Data Recorder. Retrieved on March 29, 2019; from: https://www.ntsb.gov/news/press-releases/Pages/mr20190305.aspx
- Transport Topics. (2019, March 14). Experts Doubt Turbulence Caused Crash of Cargo Jet in Texas. Retrieved on March 29, 2019; from: https://www.ttnews.com/articles/experts-doubt-turbulence-caused-crash-cargo-jet-texas
- General Electric. (2019). The CF6 Engine. http://www.geaviation.com. Retrieved on June 13, 2019; from: https://www.geaviation.com/commercial/engines/cf6-engine
- Boeing. (2019). 767 Comercial Transport. Retrieved on June 14, 2019; from: https://www.boeing.com/history/products/767.page
- Boeing. (2019). Boeing 767. Retrieved on June 14, 2019; from: https://www.boeing.com/commercial/767/