jm + flight   7

Autonomous Precision Landing of Space Rockets - Lars Blackmore
from 'Frontiers of Engineering: Reports on Leading-Edge Engineering' from the 2016 Symposium, published by the National Academies Press, regarding the algorithms used by SpaceX for their autonomous landings:
The computation must be done autonomously, in a fraction of a second. Failure to find a feasible solution in time will crash the spacecraft into the ground. Failure to find the optimal solution may use up the available propellant, with the same result. Finally, a hardware failure may require replanning the trajectory multiple times.

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Suggested Citation:"Autonomous Precision Landing of Space Rockets - Lars Blackmore." National Academy of Engineering. 2017. Frontiers of Engineering: Reports on Leading-Edge Engineering from the 2016 Symposium. Washington, DC: The National Academies Press. doi: 10.17226/23659. ×

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A general solution to such problems has existed in one dimension since the 1960s (Meditch 1964), but not in three dimensions. Over the past decade, research has shown how to use modern mathematical optimization techniques to solve this problem for a Mars landing, with guarantees that the best solution can be found in time (Açikmeşe and Ploen 2007; Blackmore et al. 2010).

Because Earth’s atmosphere is 100 times as dense as that of Mars, aerodynamic forces become the primary concern rather than a disturbance so small that it can be neglected in the trajectory planning phase. As a result, Earth landing is a very different problem, but SpaceX and Blue Origin have shown that this too can be solved. SpaceX uses CVXGEN (Mattingley and Boyd 2012) to generate customized flight code, which enables very high-speed onboard convex optimization.
spacex  blue-origin  convex-optimization  space  landing  autonomous-vehicles  flight  algorithms 
10 days ago by jm
Flawed analysis, failed oversight: How Boeing, FAA certified the suspect 737 MAX flight control system
omg this article is absolutely horrific. Boeing are in deep shit if this is borne out.
Like all 737s, the MAX actually has two of the sensors, one on each side of the fuselage near the cockpit. But the MCAS was designed to take a reading from only one of them.

Lemme said Boeing could have designed the system to compare the readings from the two vanes, which would have indicated if one of them was way off. Alternatively, the system could have been designed to check that the angle-of-attack reading was accurate while the plane was taxiing on the ground before takeoff, when the angle of attack should read zero.

“They could have designed a two-channel system. Or they could have tested the value of angle of attack on the ground,” said Lemme. “I don’t know why they didn’t.”

The black box data provided in the preliminary investigation report shows that readings from the two sensors differed by some 20 degrees not only throughout the flight but also while the airplane taxied on the ground before takeoff.
faa  aviation  boeing  737max  safety  fail  sensors  flight  crashes  mcas 
5 weeks ago by jm
Germanwings flight 4U9525: what’s it like to listen to a black box recording?
After every air disaster, finding the black box recorder becomes the first priority – but for the crash investigators who have to listen to the tapes of people’s final moments, the experience can be incredibly harrowing.
flight  disasters  metrics  recording  germanwings  air-travel  black-box-recorder  flight-data-recorder  death 
april 2015 by jm
Should Airplanes Be Flying Themselves?
Excellent Vanity Fair article on the AF447 disaster, covering pilots' team-leadership skills, Clipper Skippers, Alternate Law, and autopilot design: 'There is an old truth in aviation that the reasons you get into trouble become the reasons you don’t get out of it.'

Also interesting:

'The best pilots discard the [autopilot] automation naturally when it becomes unhelpful, and again there appear to be some cultural traits involved. Simulator studies have shown that Irish pilots, for instance, will gleefully throw away their crutches, while Asian pilots will hang on tightly. It’s obvious that the Irish are right, but in the real world Sarter’s advice is hard to sell. The automation is simply too compelling. The operational benefits outweigh the costs. The trend is toward more of it, not less. And after throwing away their crutches, many pilots today would lack the wherewithal to walk.'

(via Gavin Sheridan)
airlines  automation  flight  flying  accidents  post-mortems  af447  air-france  autopilot  alerts  pilots  team-leaders  clipper-skippers  alternate-law 
november 2014 by jm
Accident: Ryanair B738 and American B763 at Barcelona on Apr 14th 2011
An accident report concerning a Ryanair flight.

An American Airlines Boeing 767-300, registration N366AA performing flight AA-67 from Barcelona,SP (Spain) to New York JFK, NY (USA), had taxied to the holding point runway 25L and was holding short of the runway.

A Ryanair Boeing 737-800, registration EI-EKB performing flight FR-8136 from Barcelona,SP (Spain) to Ibiza,SP (Spain) with 169 passengers and 6 crew, was taxiing along Barcelona's taxiway K for departure from runway 25L and was maneouvering to pass behind the Boeing 767-300.

A number of passengers on board of the Boeing 737-800 observed the right hand wing of the aircraft contact the tailplane of the Boeing 767-300 and rose out of their seats attracting the attention of a flight attendant. A passenger told the flight attendant, that their aircraft had hit the aircraft besides them. The flight attendant contacted the purser, who instructed her to contact the flight deck, she contacted the flight deck and informed the captain that passengers had seen their aircraft had hit another aircraft. The captain responded however everything was fine and she continued with the takeoff about 2 minutes after the Boeing 767.

Immediately after departure the passengers insisted the flight was not safe and they had collided with another aircraft, one of the passengers identified himself as an engineer. The flight attendant told the engineer that the captain had been informed and had told everything was fine. No further information was forwarded to the flight deck.

After landing in Ibiza, while disembarking, the passengers again spoke up claiming the flight had been unsafe.

During the turnaround the flight attendant informed the purser that one of the passengers observing the collision was an engineer. Neither approached the flight crew however.

Following the return flight FR-8137 the purser talked to the captain and informed her that one of the passengers observing the collision was an engineer.

In the following it was identified that the right hand winglet of the Boeing 737-800 had received damage, the Boeing 767-300 was found with damage to the left hand stabilizer following landing in New York.


According to the story, it appears the AA flight crew were not informed of the potential damage to their plane before or during their transatlantic flight to JFK. (via Juan Flynn)
via:juanflynn  flight  travel  safety  ryanair  collisions 
july 2012 by jm
Air France 447 Flight-Data Recorder Transcript - What Really Happened Aboard Air France 447 - Popular Mechanics
The (comp.)risks of overautomation strike again. "When trouble suddenly springs up and the computer decides that it can no longer cope—on a dark night, perhaps, in turbulence, far from land -- the humans might find themselves with a very incomplete notion of what's going on. They'll wonder: What instruments are reliable, and which can't be trusted?"
aviation  crash  flight  flying  autopilot  stalls  warnings  alarms  ui  af447  risks  automation 
december 2011 by jm
747s using VLANs to secure in-flight access to engine management systems
'I was contracted to test the systems on a Boeing 747. They had added a new video system that ran over IP. They segregated this from the control systems using layer 2 VLANs. We managed to break the VLANs and access other systems and with source routing could access the Engine management systems.' (via Risks)
scary  aviation  flight  security  boeing  747  via:risks 
november 2011 by jm

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