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Ethiopian airliner down in Africa

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Ethiopian airliner down in Africa

Old 5th Apr 2019, 21:23
  #3361 (permalink)  
Join Date: Dec 2008
Location: PDX
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Originally Posted by MemberBerry View Post
Maybe they only applied as much electric trim as needed to bring it close to the green band, that starts at 2.5 on the MAX. The stick shaker suggesting they are close to a stall might have made them reluctant to use more.
[Not a pilot] Yet they had the control column way back (after the ground proximity warning) and, at times, called out, Pull together, and, Pitch together. They decided pitch was not enough.

I think it's still unclear whether they were both on the same page about elevator pitch, manual/electric pitch trim, and hand wheel pitch trim, but do stall concerns fit in with the above?

They spent a total of fifteen seconds working on pitch trim; first the FO, later, "together." It's not clear to me whether at any point they each freed up a hand to use on the hand wheels.

Last edited by fotoguzzi; 5th Apr 2019 at 21:32. Reason: typo; add timeframe info
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Old 5th Apr 2019, 21:24
  #3362 (permalink)  
Join Date: Aug 2013
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Simplicity, user friendliness and graceful degradation


Like you I have absolutely zero experience in modern liners like the MAX or NEO. But when reading accident and incident reports, I get the feeling that beside the lack of proper and sufficient training, the modern liners are needlessly over complex, not user friendly, have poor and unintuitive man-machine interphase and when their systems degrade, they degrade very ungracefully. I know both Airbus and Boeing pilots who all tell me their machines are a joy to fly when all bells and whistles are working properly, but I don’t understand why the manufactures have chosen to go down the path of complexity, when I know from personal experience that an aircraft can be built in another way.

I know that most normal pilots are in love with their specific aircraft type, but going through the types I have flown in my career so far, the F-16 stands out above all other types in the way it is designed. For some reason it appears that when the F-16 was designed, Boyd, Hillaker and the rest of the so-called Fighter Mafia members actually understood what the pilots needed both when every system was working, but also when things went bad. They managed to build a very simple, user-friendly and from a technical point of view genius aircraft.

To begin with, the flight control system, the worlds first full FBW system in a combat aircraft, was very effective, robust, simple, reliable (when the first hiccups were dealt with) and best of all, so fantastically pilot friendly, that most pilots will feel that the aircraft becomes an extension of their body after half the take-off run on their first flight in the aircraft.

I don’t understand why it is not possible to build an airliner with such a clever flight control system? As you described, who needs dedicated flap levers? You only need flaps during take-off and landings, so why not integrate the flap function with the gear handle, as you need your gear to be down when taking off or landing. Flaps that can be manually selected down without the landing gear if a situation ever arises where it is needed (intercepting a cessna at 90 knots), and flaps that will retract by themself if an overspeed is about to happen. And by the way, the system changes the control gains from take-off/landing gains to cruise gains with the gear handle position. Automatic leading edge flaps that drop down on rotation to increase lift, and instantly go up to dump lift when touching down on landing. No need to arm them like spoilers and no need to stow them in case of rejected landing. A wing that changes shape (again by the use of leading edge flaps), so as to always have the optimal shape for the actual flight regime (with an envelope much wider than the typical airliner).

And in the very rare case where the system malfunctions, it degrades so gracefully that the pilot probably wont even notice any change in flying characteristics (like when the bus changes to direct law). Loose a control surface (loose like in it has fallen off), have a runaway elevator trim go full nose down, or even worse, have a LEF pointing straight up like in gums LEF incident, and still be able to counteract the roll, pitch or yaw with less then superhuman power, by just applying a bit more force then normal on the side stick.

And all this was designed in the mid 70’s. One would think that it would be possible to make an even better flight control system today. A system that would help the pilots instead of defeating them. Of course, complex systems are fine and work well if the operators are well trained, experienced pilots that understand the systems and all of their sub modes, but the average pilot today as I see him/her, is only trained to the minimum requirements, doesn’t get a lot of stick time, and doesn’t really understand the system 100%.

Aircraft engineers, is it not possible to keep it simple stupid anymore?
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Old 5th Apr 2019, 21:29
  #3363 (permalink)  
Join Date: Jun 2006
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Originally Posted by Bleve View Post
I don’t fly the 737 Max, but after doing a bit of ‘what-if-ing’, I’ve come to the conclusion that if I were a Max pilot and had stick shaker on take-off, I would not fully retract the flaps. I would retract to Flaps 1. My experience on other Boeing’s (767 & 744) is that Flaps 1 provides the best manoeuvre margin to the stall and in the 737 Max would prevent MCAS doing it’s (evil) thing.
That's what I learned from LionAir, except that I would have left the flaps at 5 and adopted a pitch attitude of 10 degrees, confirmed that the stick shaker was false, checked for IAS disagree, and set 80% N1 (terrain permitting), flight directors and autothrottle off. Climb above a safe altitude and then carefully run the Airspeed Unreliable checklist, which would identify correct speed on the RHS. Engage autopilot B as per the checklist and return to land. Don't retract flaps. MCAS won't activate and stab trim cutout switches can remain in normal.

Now, I concluded that from the comfort of my armchair AFTER the Lion Air accident, so that if it happened to me, I would know what to do.

The Ethiopian crew obviously didn't, but neither did Boeing.

Mind you, I AM adopting a Boeing procedure here (the Airspeed Unreliable checklist) - It's just that I'm being choosey about which Boeing procedure to adopt and how, and using some additional system knowledge which we didn't have prior to the Lion Air report (i.e. flaps stops MCAS!).
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Old 5th Apr 2019, 21:35
  #3364 (permalink)  
Join Date: Jan 2008
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I think engineers have more freedom when designing fighters, then when designing airliners.
It’s all about liability.
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Old 5th Apr 2019, 21:43
  #3365 (permalink)  
Join Date: Dec 2015
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Originally Posted by astonmartin View Post
I think engineers have more freedom when designing fighters, then when designing airliners.
It’s all about liability.
I think piggybacking onto a 50 year old airframe may be more of an obstacle, than any legal liability is, when designing flight controls.
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Old 5th Apr 2019, 21:51
  #3366 (permalink)  
Join Date: Feb 2013
Location: 60 north
Age: 57
Posts: 19
ViperBoys et al

I trained 50 or 60 active Dutch F16 chaps in AMS on MCC Courses.
5 sessions in FFS A320 and later in B737-800
An absolute delight, BUT as they all remarked on the last night at the mandatory WetBrief.
" Dude, we respect You civilians a bit more now"
The thing is that the A320 was easy for them, when they realized , NO 4 handed , lightning quick selections!!
The Boeing 737 they wondered about?
"Which Museum did You steal this rig from"

In short:
Civil aviation has gone backwards since say mid 1990s.
I suspect the latest events will do to Aircraft Design and Certification what 9/11 did to Airport Security.
Without any direct comparison intended from me, of-course.
Cpt B

PS There is 9 flap settings on the 737.
I rest my case.

Last edited by BluSdUp; 5th Apr 2019 at 21:56. Reason: Added PS
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Old 5th Apr 2019, 21:53
  #3367 (permalink)  
Join Date: Apr 2008
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F-16Guy I think you really know the an$wer.
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Old 5th Apr 2019, 21:59
  #3368 (permalink)  
Join Date: Feb 2013
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Ibiza for 15£
Sorry 9£
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Old 5th Apr 2019, 22:00
  #3369 (permalink)  
Join Date: Dec 2018
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Originally Posted by BuzzBox View Post
So what happens next time somebody has a different type of problem for which they have had no specific training?
Depends on what the problem is.

If the problem is ill thought-out automation, incomplete documentation and missing training, then the answer will be fix the automation, revise the documentation and add training.

Which is what Boeing are doing here.
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Old 5th Apr 2019, 22:05
  #3370 (permalink)  
Join Date: Nov 2007
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The isolation for MCAS is the STAB OFF switches beside pilots knee. Anything that moves the stab goes through these switches. But, you would have to recognize the problem. Clearly the pilots knew nothing about MCAS like the rest of us. All they may have seen is the STAB running AND - nose down.
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Old 5th Apr 2019, 22:10
  #3371 (permalink)  
Join Date: Aug 2005
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It might be worth looking into an older crash A6-FDN. FDB 981. Strange that a 5000h PF sets 12 seconds of continuos stab down trim from which he could not recover. Was not a MAX.
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Old 5th Apr 2019, 22:39
  #3372 (permalink)  
Join Date: May 2016
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Originally Posted by Airbubba View Post
I still can't figure out why nobody pulled back the power with continuous overspeed warnings on both sides and obviously too much thrust for attempted level flight.
Attempted level was FL320 !

With stall warning and attempting to clear the terrain, more speed means more potential energy, so I think overspeed was not on top of their priorities.

If Boeing NNC for trim runaway had included "reduce speed if manual trimming is too hard", perhaps they would have done it...
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Old 5th Apr 2019, 22:50
  #3373 (permalink)  
Join Date: Apr 2015
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Originally Posted by yanrair View Post
The isolation for MCAS is the STAB OFF switches beside pilots knee.
That's not isolation, it disables all electric trim. Isolation would mean disabling MCAS only.

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Old 5th Apr 2019, 22:53
  #3374 (permalink)  
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Woof woof, it's dark here....

So the dog that hasn't barked, as far as I know, is this:

Aside from the three-crew Lion Air flight that preceded the mishap flight, where are all the crews who might have experienced an AoA failure that triggered MCAS at flaps-up, and handled the situation safely?

For this to happen means that one of the AoA sensors has to be bad from the start, that it has to be bad enough to call a spurious stall warning, and it has to be the sensor that is driving MCAS on this flight (the last being a 50:50 chance). How often has this happened in the MAX's history? I have not seen a single such account in this long thread (I stand corrected if I missed one).

Clearly, that number would provide some valuable context to the two occurrences when the result has been fatal.
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Old 5th Apr 2019, 23:02
  #3375 (permalink)  
Join Date: May 2016
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Originally Posted by nevillestyke View Post
But reducing power pitches nose down, due to the aerodynamics of the aircraft. How much would airspeed reduce? Parking brake is of little use.
The nose up moment of the engines thrust may be important at lower speeds, but negligible at higher speeds, since the thrust is constant but any other aerodynamic moments vary as the square of speed.

What about the pitch of airbrakes ?
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Old 5th Apr 2019, 23:06
  #3376 (permalink)  
Join Date: Mar 2014
Location: Birmingham, UK
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Does anyone else think that maybe the very fact that they're trying to solve this through a software update may be part of the problem?
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Old 5th Apr 2019, 23:14
  #3377 (permalink)  
Join Date: Apr 2015
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Originally Posted by AndyJS View Post
Does anyone else think that maybe the very fact that they're trying to solve this through a software update may be part of the problem?
I'm pretty sure that, as we learn more and more about the underlying issues, more people think just that, every day. I think a lot of us who have been following this closely will be surprised if the MAX gets back in the air quickly, with only a new software patch.
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Old 5th Apr 2019, 23:17
  #3378 (permalink)  
Join Date: Nov 2010
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Aviation Week: MAX Saga Spotlights Flight-Deck Human Factors

MAX Saga Spotlights Flight-Deck Human Factors

MAX Saga Spotlights Flight-Deck Human Factors

Sean Broderick, Bill Carey and Ben Goldstein Washington

Details emerging from investigations into two fatal Boeing 737-8 MAX accidents in five months are fueling a heated debate over whether the pilots involved were adequately prepared to face their inflight emergencies or simply could not overcome failure modes rooted in a flawed design. Either scenario implicates flight-deck human-factors shortcomings that will reverberate far beyond the software upgrades Boeing is counting on to help get the 737 MAX fleet flying again.

While the investigations into the Oct. 29, 2018, crash of Lion Air Flight 610 (JT610) and the March 10 Ethiopian Airlines Flight 302 (ET302) accident are ongoing, links between the two have been established. In each case, the flight crews battled to keep a new 737-8 aloft while the aircraft’s Maneuvering Characteristics Augmentation System (MCAS) pushed the nose down by applying stabilizer trim. The MCAS, which was added to the 737 speed trim system to help the new model handle like its 737NG predecessor in certain flight profiles, relies on data from one of the MAX’s two angle-of-attack (AOA) vanes. In each accident, investigators have confirmed the aircraft was getting unreliable data from an AOA vane, which triggered repeated MCAS nose-down inputs.

Boeing is developing a software upgrade that will prevent the updated system from activating if it is fed erroneous data (see page 24). It also gives pilots ultimate elevator authority by limiting the degree of automatic nose-down stabilizer. Additional training and updated flight manuals will also be provided. These changes will be part of safety regulators’ demands to lift 737 MAX revenue-service operations bans that have grounded the 376-aircraft fleet since March 13.

The changes are a de facto admission that the MCAS needed improvement. Beyond that, questions about how well-prepared pilots were to deal with the system’s failure remain paramount in many circles. Boeing did not include any MCAS information in 737 MAX flight manuals, which some point to as an egregious oversight. It was only after JT610 that Boeing provided pilots with extensive details about handling the MCAS.

Many pilots say that though they do not agree with Boeing’s philosophy of keeping the system in the background, they acknowledge Boeing’s logic that an MCAS failure would be recognized as uncommanded stabilizer input and managed via the common “stabilizer runaway” checklist was reasonable. The checklist, which is the same on the 737NG and MAX and includes a step that cuts power to the stabilizer, is supposed to be common knowledge for airline pilots.

“Pilots of large aircraft are trained from Day 1. When the pitch of the aircraft is doing something you’re not telling it to do, you do a runaway pitch trim checklist,” Acting FAA Administrator Dan Elwell, a former airline pilot, told a U.S. Senate subcommittee during a March 27 hearing about the MAX. “In every plane I’ve ever flown, it’s called a memory item. You’re not fumbling through books. It’s a time-critical procedure, and you go to that.”

The European Aviation Safety Agency Executive Director Patrick Ky, speaking to European Parliament members on March 19, said the procedure “is not that complicated.” But the fact that it was not followed by the Lion Air crew suggests they were confused. “If they knew what was really happening, they would not have done what they did, and they would not have crashed,” Ky said.

The ET302 crew had the benefit of knowing about the MCAS, and investigators determined that they followed the prescribed procedure—at least in part. The MCAS activated and pushed the aircraft’s nose down. The crew responded with manual inputs via column-mounted trim switches, which countered only a portion of the MCAS nose-down input. The automated system, still receiving erroneous data, activated two more times, dropping the nose even more. After the third MCAS nose-down input, the crew toggled the cutout switches. Struggling to maintain altitude, they turned the system back on, which triggered the MCAS again.

Investigators are looking closely at how the ET302 crew reacted, and why they reactivated a system that they identified as central to their problem. One possibility: With power to the stabilizer cut off, they would have needed to move it by cranking a center-console-mounted wheel attached to cables and pulleys. This may have taken more time than they believed they had, or been too difficult, so they opted to reengage stabilizer power and try the column-mounted switches.

Another possibility: They may not have fully understood what they were facing. Boeing’s approach of keeping the MCAS in the background means its activation did not result in any cockpit warnings. Boeing’s assumption: Unwanted nose-down inputs, signified in part by a spinning trim wheel, would alert pilots to a runaway stabilizer and prompt them to execute the checklist.

“If I had been flying a MAX with stickshaker activation at liftoff after the Lion Air accident, shutting off the trim would have been accomplished in a matter of seconds, not minutes,” says one U.S.-based MAX pilot. “I probably would have activated the stabilizer trim cutout switches before the gear was even up. Why that didn’t happen on the Ethiopian flight is a mystery to me.”

The stickshaker warning, or artificial vibrating of the control column that signifies a stall is imminent, activated on both JT610 and ET302 because of the faulty AOA data. Meant to alert pilots of a problem, it can be more of a distraction than a help in certain scenarios,the MAX pilot says.

“Not only would the noise mask the operation of the trim [wheel], it is such a significant warning that it would command a lot of attention,” the pilot says. “Ultimately, it is not telling you anything useful, but it makes recognizing the trim runaway more difficult,especially since the trim was not continually running.”

The two MAX accidents underscore a larger concern: Is automation is beginning to supplant, instead of augment, basic flying skills? While airlines have long used it safely, pilots who typically fly with automation who were involved in accidents “made errors when confronted with an unexpected event or [when] transitioning to manual flying,” the Transportation Department Inspector General’s office found in a 2016 report to Congress.

“As a result, reliance on automation is a growing concern among industry experts, who have questioned whether pilots receive enough training and experience to maintain manual flying proficiency,” Transportation Department Inspector General Calvin Scovel said in the March 27 hearing. The initial results from the ET302 accident “raise concerns about pilots’ abilities to recognize and react to unexpected events,” he added.

The FAA now requires that Part 121 pilots be trained in specific abnormal flight conditions, including stall and upset recovery and loss of reliable airspeed, and that training on the responses be performed in full-flight simulators. But the recent 737-8 accidents have raised questions about the availability and capabilities of simulators, Scovel says. According to the FAA, “existing simulators do not fully replicate the 737 MAX aircraft, and no U.S. airline currently has a MAX simulator,” he says.

Most airline standard operating procedures “recommend and encourage” using full automation to control an aircraft for safety and efficiency reasons, observes Hassan Shahidi, Flight Safety Foundation (FSF) president and CEO. Automated systems can improve pilots’ management of the flightpath, particularly during reduced weather minima, relieving them from repetitive tasks. But by depending on automation, they revert to monitoring the system rather than actively flying the aircraft. There are various theories about how complacency affects pilot performance, says Shahidi, a former Mitre Corp. senior executive who started at FSF in January.

With all of the advantages it confers, automation is not a substitute for the function of the pilot, who ultimately is responsible for flying the aircraft, says Shahidi. With respect to pilot training, “there needs to be sufficient understanding for the basis of the automation—why there is automation in the first place—and what happens with partial or full-use” of a system, he says. Also, pilots should understand the importance of monitoring an expected function so they can take timely and corrective action if there is a malfunction.

Training that focuses pilots on abnormal situations is important, whether in a simulator or non-simulator environment, Shahidi advises. For example, pilots who fly with the autothrottle engaged, even in small aircraft, may lose the habit of regularly scanning the speed indicator. When the autothrottle disengages for some reason, the pilot may not readily notice or react to even large speed

“Automation has the potential to cause significant issues if it is misunderstood,” says Shahidi. “Poor automation can reduce the pilots’ situational awareness and create significant workload as they are trying to figure out what the automation is doing, especially if the system fails. This certainly can lead to an aircraft getting into an undesirable state from which it is difficult or sometimes impossible to recover.”

The FSF issued a position paper on pilot training and competency in March 2018 saying the commercial aviation industry has reached a “crossroads” in determining how pilots should be trained and mentored and questioning whether the current approach can produce a “sustainable quantity and quality of pilots” for the expected future demand. Boeing has forecast a need for 790,000 new civil aviation pilots over the next 20 years. The Asia-Pacific region leads demand with a requirement for 261,000 new pilots over that time, the manufacturer predicts.

Shahidi concurs when asked if there is a need for more standardized pilot training across airlines that have different standard operating procedures and training requirements beyond what is minimally required by aviation authorities and manufacturers.

“Moving forward, especially in light of the fact that we’re looking at significant demand for new pilots in many of these regions, it is important to harmonize the level of training that is required,” he says.

Among the recommendations the FSF white paper calls for are “competency- or evidence-based” training programs that are not solely hours-based and for maximized use of simulation devices. Pilot performance criteria should be universally recognized, and the International Civil Aviation Organization tapped to define guidelines for the performance required of flight academies.

Shahidi points to the role of what he calls nontechnical competencies of communications, analysis, problem-solving, decision-making and leadership in piloting an aircraft. “It is not just understanding [which buttons to push] or disengage, but—as part of a holistic approach to training—these basic skills are important,” he says.

Fundamentally, mastering these skills is both more realistic and more valuable than practicing scores of failure-scenario combinations.

“We are not trained in many potential emergency situations,” says the U.S.-based MAX pilot. “But we are trained to fly the airplane, prioritize, work together and diagnose whatever problem is facing us. In fact, I think just about every diversion I’ve had for mechanical problems has been for something we did not train for.”

The FAA is working on guidance that stems from a 2013 working group report on flightpath management system usage that includes 18 recommendations. Much of the report’s focus is on how automation is both helping and hindering pilots. The anticipated guidance is expected to address several recommendations, including one on creating policy that airlines can integrate seamlessly into their own operations.

“The policy should highlight and stress that the responsibility for flightpath management remains with the pilots at all times,” the report says. “Focus the policy on flightpath management, rather than automated systems. Note that this policy would contain what has previously been named an ‘automation policy’ and would be broader, to emphasize flightpath management.”

Aviation Week & Space Technology April 8-21, 2019 page 26-28
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Old 5th Apr 2019, 23:18
  #3379 (permalink)  
Join Date: May 2016
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Originally Posted by OldnGrounded View Post
I'm pretty sure that, as we learn more and more about the underlying issues, more people think just that, every day. I think a lot of us who have been following this closely will be surprised if the MAX gets back in the air quickly, with only a new software patch.
People got used to software updates... Windows needs updates after each security fault detected, Boeings need an update after each crash
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Old 5th Apr 2019, 23:28
  #3380 (permalink)  
Join Date: Apr 2019
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Fly Dubai 981

As edlb pointed out, there are some similarities. It is, however, a non max and a 12 sec AND trim.

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