By this point the amount of force he needed to apply to the control column to keep the nose level was pushing him to the limit of his physical ability. Kick! he shouted. A new jackscrew has a gap less than 0.010-inch. The 2 pilots, 3 cabin crewmembers, and 83 passengers on board were killed, and the airplane was destroyed by impact forces. On 31 January 2000, Alaska Airlines Flight 261's trimmable horizontal stabilizer jams and breaks free from its control system. In fact, by now there were several other airplanes in the area that were keenly watching the unfolding situation. Like the end play check intervals, Alaska Airlines received FAA permission to extend their jackscrew lubrication intervals four times from 1987 to 1996 with no supporting data. N963AS nearly made it anyway its next jackscrew inspection was scheduled for March 2000. It really wants to pitch down., Alaska two six one, said the controller, Say your condition?, Two six one, we are at 24,000 feet, kinda stabilized, said Thompson. Robo ^Tir in Autos & Vehicles. Thompson along with Captain Bill Tansky had just pulled out of an uncommanded dive from 31,000 feet to 23,000 feet. Thus the fundamental principle of redundancy was violated. Alaska Airlines' maintenance and inspection of its horizontal stabilizer activation system were poorly conceived and woefully executed. The threads eventually lost up to 90% of their thickness, compared to 22% at the maximum wear depth of one millimeter. The McDonnell Douglas MD-8-61 was made in Long Beach and was then . The stop nut was not designed to hold the aerodynamic tail loads. The only layer of protection against a catastrophe was therefore the assumption that poorly trained, low-paid maintenance workers would apply enough grease. For the relatives of the victims, this fact made it all the more important that Alaska Airlines pay for its negligence. The grease was green in color and differed from Boeings specified grease, Mobilegrease 28, which was red. It was found that the use of Aeroshell 33 was not a factor in this accident. In NTSB board member John J. Goglia's statement for the final report, with which the other three board members concurred, he wrote: This is a maintenance accident. The design of the jackscrew on the MD-80 series was identical to that of the original 1960s-era Douglas DC-9, which was certified to meet requirements stating that no reasonably probable single failure of the control system could jeopardize the controllability of the airplane. The block-on-ring test rigs were lubricated with grease where they made contact. how to print presenter notes in canva alaska airlines flight 261 pilot drunk. [5] Captain Theodore "Ted" Thompson, 53, had accrued 17,750 flight hours, and had more than 4,000 hours experience flying MD-80s. Some applied grease only through the single zirk fitting of the acme nut we learned that numerous pumps of the grease gun did not provide enough grease on the jackscrew after it was run up and down. It was really tough there for a while.. Performing an upset recovery maneuver, the captain commanded to "push and roll, push and roll," managing to increase the pitch to -28 degrees, he stated, "ok, we are invertedand now we gotta get it. The anger he must have felt is difficult to fathom. What I want to do is get the nose up, and then let the nose fall through and see if we can stab it when its unloaded. It was his belief that the stabilizer might move nose up if there was no aerodynamic force pushing it upward into the nose down position. More than half of these were directly related to jackscrew lubrication and end-play measurement. This is the only time the award has ever been given posthumously. When the stabilizer moves upward, downforce on the tail decreases, and the nose pitches down; similarly, when the stabilizer moves downward, downforce increases, and the nose pitches up. Whatever we did is no good, dont do that again, said Tansky. [15], Alaska Airlines Flight 261 departed from Puerto Vallarta's Licenciado Gustavo Daz Ordaz International Airport at 13:37 PST (21:37 UTC), and climbed to its intended cruising altitude of flight level310 (31,000 feet or 9,400m). The mechanic went to federal authorities in late 1998 claiming the airline was cutting back on maintenance and falsifying records to get planes back into operation faster. At 16:09, he said, Im gonna click it off. More importantly, investigators felt that the pilots should not have attempted to troubleshoot the problem after exhausting the procedures in the checklist, considering that they didnt know the extent of the damage. These aircraft immediately contacted the controller. The criminal investigation also proved to be a disappointment. Having decided not to touch the trim system anymore, the crew now performed some final tests of the airplanes low speed handling. [27], In 1998, an Alaska Airlines mechanic named John Liotine, who worked in the Alaska Airlines maintenance center in Oakland, California, told the FAA that supervisors were approving records of maintenance that they were not allowed to approve or that indicated work had been completed when, in fact, it had not. [26], The investigation then proceeded to examine why scheduled maintenance had failed to adequately lubricate the jackscrew assembly. A flight traveling from Mexico crashed into the Pacific Ocean on Jan. 31, 2000. [19]:69 During this time, the flight crew considered, and rejected, any further attempts to correct the runaway trim. I clicked it off, Thompson said. Okay, we had a big bang back there, said the flight attendant. Yeah, I heard it, said Thompson. Just before plunging into the Pacific Ocean, the crew of Alaska Airlines Flight 261 flew upside down while desperately trying to regain control of the passenger jet, investigators confirmed Thursday. Performing maintenance less frequently saved on labor costs and kept the planes in the air longer, thus increasing revenue. Home From C-Check to Tragedy: Lessons Learned from Alaska flight 261. Folks, we have had a flight-control problem up front here, first officer Ted Thompson told the passengers over the PA system. [6]:9 The crippled plane had been given a block altitude,[20] and several aircraft in the vicinity had been alerted by ATC to maintain visual contact with the stricken jet. An Alaska Airlines pilot, involved in the investigation of the horrific crash of Alaska Flight 261, has listened to the cockpit voice recorder from the downed plane and he reported that for the . When he measured the wear on the jackscrew nut and found it to be exactly one millimeter (0.040in), he concluded that the nut had reached the end of its service life and issued a work card ordering its replacement. I cant reach it! said Tansky. A special inspection by the FAA after the accident found further evidence of a massively deficient safety culture at Alaska Airlines. The longer it went without being greased properly, the faster the jackscrew wore down the threads on the nut. If youve got any hidden circuit breakers wed love to know about em. Over the next couple minutes the pilots reported to maintenance that electrical current was present when they activated the trim motors, but that the motors nevertheless could not move the stabilizer. Hands clenching my headphones, I listened to the crew talk among themselves, with airline dispatch and to air traffic controllers in an attempt to keep the airplane kinda stabilized as they put it. Flight 261 was on its way from Puerto Vallarta to San Francisco when a mechanical failure caused it to plunge into the ocean, killing all 88 people on board. The basic design of the stabilizer is relatively simple. Increasing the interval between lubrications meant that every lubrication had to be done correctly in order to prevent accelerated wear and tear. They sounded experienced, calm and professional. Finally, at 16:19 and 21 seconds, the stop gave way with a faint thump. The horrific crash killed all 88 people on board and raised troubling questions about one of Americas largest airlines. As flight 261 climbed through 23,400 feet at approximately 13:49 that day, the badly worn threads started to tear away from the nut, wrapping themselves around the jackscrew and causing the stabilizer to jam. Investigators later uncovered a critical maintenance issue with the aircraft, which meant that even after the flight crew deployed the speed brakes and control surfaces on the wings, they still could not stop the tragic crash.Join aviation engineers and experts to uncover the reasons behind some of the worlds most unforgettable plane crashes. The last minutes of those on board the doomed MD-83 would have been sheer hell, as the plane went inverted, corkscrewed, pirouetted, and spun like a top during its final dive. [6], Systemic problems were identified by the investigation into the FAA's oversight of maintenance programs, including inadequate staffing, its approval process of maintenance interval extensions, and the aircraft certification requirements. Alaska flight 261 departed Puerto Vallarta, Mexico at 1:37 pm on January 31, 2000 destined for San Francisco. The aircraft designers assumed that at least one set of threads would always be present to carry the loads placed on it; therefore, the effects of catastrophic failure of this system were not considered, and no "fail-safe" provisions were needed. This movement occurs via an electrical motor that turns a two-foot-long steel jackscrew through an aluminum-bronze acme nut held fixed within the vertical fin. Keep in mind that the pitch of the stabilizer itself is actually inverse to the pitch of the airplane.). Were pretty busy up here working this situation. The tests also simulated the acme nut wear process by using blocks milled from a scrap acme nut and rings turned from a jackscrew forging. Saudi Arabian Airlines Flight 763/Kazakhstan Airlines Flight 1907 Crash Documentary - Sigh. [6], Between 1985 and 1996, Alaska Airlines progressively increased the period between both jackscrew lubrication and end-play checks, with the approval of the Federal Aviation Administration (FAA). 0:27. Over the course of the investigation, the NTSB considered a number of potential reasons for the substantial amount of deterioration of the nut thread on the jackscrew assembly, including the substitution by Alaska Airlines (with the approval of the aircraft manufacturer McDonnell Douglas) of Aeroshell 33 grease instead of the previously approved lubricant, Mobilgrease 28. Bouquets of flowers started arriving at the company's headquarters in SeaTac, Washington the day after the crash. The acme nut was constructed from a softer copper alloy containing aluminum, nickel, and bronze. If the end play is over 0.040 inch, the $80,000 jackscrew/nut assembly must be replaced. Around that time, Alaska Airlines agreed to settle the libel suit by paying about $500,000; as part of the settlement, Liotine resigned.[28]. Nevertheless, investigators praised the pilots for their heroic last-ditch efforts to save their aircraft, even attempting to fly upside down when they found they could not level the plane. The effect was immediate and catastrophic, as his inputs ripped out whatever threads remained on the jackscrew nut. Unfortunately, these components that I needed to examine were laying under 200 feet of water. N963AS, the plane that would later become Alaska Airlines flight 261, was one of many in the airlines fleet that was subject to these marginal maintenance practices. To evaluate what role grease played in the accelerated wear of the jackscrew, the NTSB formed a Grease Group and conducted standardized tests on both Aeroshell 33 and Mobilgrease 28. A flight attendant opened the cockpit door, and Captain Thompson briefed her on the situation. [6], Beginning at 16:19 (00:19 UTC), the CVR recorded the sounds of at least four distinct "thumps", followed 17 seconds later by an "extremely loud noise", as the overstrained jackscrew assembly failed completely and the jackscrew separated from the acme nut holding it in place. So theyre trying to put pressure on you, said Tansky. The trim might be, and then it might be uh, if somethings popped back there. The seemingly simple task of greasing the jackscrew was not immune to this degradation of the maintenance environment. The US aviation industry has nevertheless managed to go a long time without another major crash, but as for whether something like Alaska 261 could happen again well, never say never. Were going to LAX, Thompson told the dispatcher. And while the airline did eventually settle the suits, it did so only after dragging the families through what many described as a legal hell in which Alaskas lawyers tried to downplay the monetary value of their deceased loved ones. Alaska Airlines' extension of its lubrication interval for its McDonnell Douglas MD-80 horizontal stabilizer components, and the FAA's approval of that extension, the last of which was based on McDonnell Douglas's extension of the recommended lubrication interval, increased the likelihood that a missed or inadequate lubrication would result in the near complete deterioration of the jackscrew-assembly acme-nut threads, and therefore, was a direct cause of the excessive wear and contributed to the Alaska Airlines Flight 261 accident; Alaska Airlines's extended end-play check interval and the FAA's approval of that extension, allowed the acme-nut threads to deteriorate to the point of failure without the opportunity for detection; The absence on the McDonnell Douglas MD-80 of a fail-safe mechanism to prevent the catastrophic effects of total acme nut loss. And so it was that on a sunny day in January 2000, 83 passengers and five crew boarded Alaska Airlines flight 261 in the resort city of Puerto Vallarta, Mexico, bound for San Francisco, California. Sometime before 15:49 (23:49 UTC), the flight crew contacted the airline's dispatch and maintenance-control facilities in SeaTac, Washington, on a company radio frequency shared with operations and maintenance facilities at Los Angeles International Airport (LAX), to discuss a jammed horizontal stabilizer and a possible diversion to LAX. [6] The captain replied: "I need to get down to about ten, change my configuration, make sure I can control the jet and I'd like to do that out here over the bay if I may. Nearly three years after the accident the NTSB determined that the probable cause of the flight 261 tragedy was a loss of airplane pitch control resulting from the in-flight failure of the horizontal stabilizer trim system jackscrew assemblys acme nut threads due to excessive wear resulting from Alaska Airlines insufficient lubrication of the jackscrew assembly. The Board also ruled that factors contributing to the accident were the airlines extended lubrication interval and the FAA approval of that extension, which increased the likelihood that a missed or inadequate lubrication would result in excessive wear of the acme nut threads. The same was cited for the airlines extended end play check interval which allowed the excessive wear of the acme nut threads to progress to failure without the opportunity for detection. Boeing also was cited as a factor due to the absence of a fail-safe mechanism to prevent the catastrophic effects of total acme nut thread loss.. Brand new season of Air Crash Investigation, Mondays at 8pm, only on National Geographic UK The UK home of National Geographic. As any good crew should do, Thompson and Tansky then pulled out the checklists for a runaway or inoperative stabilizer. The turn of the millennium had just come and gone, and the future again seemed limitless. Over time, this minute difference will cause the jackscrew to wear away the threads on the nut if metal-on-metal contact is allowed to occur. [6], The jackscrew assembly was designed with two independent threads, each of which was strong enough to withstand the forces placed on it. This and other evidence suggested to the NTSB that "the SFO mechanic who was responsible for lubricating the jackscrew assembly in September 1999 did not adequately perform the task". From the best and brightest scientists, explorers, photographers, and filmmakers, Nat Geo is the world's premium destination for science, exploration, and adventure. Navy. [6], A special inspection conducted by the NTSB in April 2000 of Alaska Airlines uncovered widespread significant deficiencies that "the FAA should have uncovered earlier". Holy shit, said Thompson, pulling back hard on the controls. citizens. We also discovered that the airline, with no objection from the FAA, was allowed to extend the end play check interval years before the accident (see graphic 9). The scenes in this video are from the documentary series Air Crash Investigation.None of them belong to me.https://en.m.wikipedia.org/wiki/Alaska_Airlines_Fl. "[6]:8 Later, during the public hearings into the accident, the request by the pilot not to overfly populated areas was mentioned. Stepping on the rudder pedals while upside down was no easy task. They've. Salvage vessels had to be brought in to raise the rest of the plane from the bottom of the Pacific Ocean. [44][45], As of May 2022, Flight 261 no longer exists, and Alaska Airlines no longer operates the Puerto VallartaSan FranciscoSeattle/Tacoma route. [6], Using side-scan sonar, remotely operated vehicles, and a commercial fishing trawler, workers recovered about 85% of the fuselage (including the tail section) and a majority of the wing components. [32][33], Captain Thompson and First Officer Tansky were both posthumously awarded the Air Line Pilots Association Gold Medal for Heroism, in recognition of their actions during the emergency. When greased regularly, the nut on the MD-80 series is designed to last for 30,000 flight hours before requiring replacement long enough that most planes will see only two or three different jackscrew nuts during their entire time in service. Fuck me!. Only by applying a continuous maximum nose up elevator input on his control column, a task which required enormous physical effort, was Captain Thompson able to maintain level flight.
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