The University of Sheffield Department of Automatic Control and Systems Engineering Course Description and Requirements., (629,13236R) B McLean, D. Automatic Flight Control Systems, Prentice-Hall, 1990 (629.135M) B Hull, D. Fundamentals of Airplane Flight Mechanics, Springer-Verlag Berlin Heidelberg, 2007.

• Aircraft Flight Control Systems
• Automatic Control Systems Pdf Free

A parking lot at in Seattle, Washington, filled with undelivered aircraftDate. Lion Air accident: October 29, 2018.

Ethiopian Airlines accident: March 10, 2019. First grounding: March 10, 2019 ( 2019-03-10) by. Effectively a worldwide grounding: March 13, 2019 ( 2019-03-13) by the (FAA)DurationOngoing. 7 months and 10 days (since March 10, 2019)CausePrecautionary measure following two similar crashes less than five months apartDeaths346:. 189 on.

157 onIn March 2019, and airlines around the world the passenger after two MAX 8 aircraft crashed, killing all 346 people aboard. The accidents befell on October 29, 2018 and on March 10, 2019.

Ethiopian Airlines was first to ground its MAX fleet, effective the day of its accident, and one day later, March 11, China's ordered the first regulatory grounding. Most other agencies and airlines followed suit over the next two days. (FAA) initially reaffirmed airworthiness of the MAX on March 11, but grounded it on March 13. The groundings affected 387 MAX aircraft serving 8,600 weekly flights for 59 airlines.In each accident, the aircraft experienced repeated nose dives and crashed soon after takeoff.

Unofficially, the cause is attributed to the airplane's new automated flight control, the (MCAS), acting on erroneous data to force the aircraft down. Pilots were unaware of MCAS, which Boeing did not describe in the airplane manuals. In November 2018, in response to the first accident, Boeing issued a referring pilots to an existing recovery procedure, and the FAA issued an mandating revisions to the crew manual. Boeing began changes to the MCAS software, flight control computer system and cockpit displays. In April 2019 the company admitted that MCAS was activated in both accidents.After the second accident, the (DOT), and a nine-member Joint Authorities Technical Review (JATR) team investigated FAA of the MAX, particularly whether the FAA delegated excessive authority to Boeing to.

The probes revealed MCAS weaknesses and instrument failures that Boeing knew of but withheld from the FAA. In September 2019, the U.S. (NTSB) faulted Boeing's assumptions that any pilot could quickly counter MCAS by using existing flight control procedures. The JATR criticized the FAA's incomplete understanding of MCAS and how interacted with automation.Boeing suspended deliveries and reduced production of the MAX, and airlines canceled thousands of flights that used the aircraft. After repeated delays in recertification, several airlines, including in the U.S. And Canada, announced MAX flights would not resume until early 2020. As of September 2019, the grounding cost Boeing up to $8 billion in revenue and compensation to airlines and bereaved families.

Boeing also faced lawsuits from airline pilots and families of victims. PK-LQP, the aircraft involved in the crash ofOn October 29, 2018, Indonesian from in to in crashed into the 12 minutes after takeoff. All 189 passengers and crew were killed in the accident. The preliminary report tentatively attributed the accident to the erroneous angle-of-attack data and automatic nose-down commanded by MCAS. The defective angle-of-attack vane was a 'dubious' used part that had been replaced on the captain's side.

The 737 MAX aircraft was delivered 2 months and 16 days prior, on August 13, 2018. This is the deadliest crash involving the Boeing 737 regardless of variant.Boeing published a supplementary service bulletin addressing the AoA warning and the pitch system's potential for repeated activation, all without referring to MCAS by name. The bulletin describes warnings triggered by erroneous AoA data, and referred pilots to a 'non-normal runaway trim' procedure as resolution, specifying a narrow window of a few seconds before the system's next application. The FAA issued an 2018-23-51, requiring the bulletin's inclusion in the flight manuals, and that pilots immediately review the new information provided.

Ethiopian Airlines Flight 302. ET-AVJ, the aircraft that crashed asOn March 10, 2019, from in to in, Kenya, crashed six minutes after takeoff near, killing all 157 passengers and crew aboard the aircraft. The 737 MAX was delivered 3 months and 23 days prior, on November 15, 2018, two weeks after the Lion Air accident.Initial reports indicated that the Flight 302 pilot struggled to control the airplane, in a manner similar to the circumstances of the Lion Air crash. A stabilizer trim found in the wreckage was set to put the aircraft into a dive.

Experts suggested this evidence further pointed to MCAS as at fault in the crash. After the crash of flight ET302, Ethiopian Airlines spokesman Biniyam Demssie said in an interview that the procedures for disabling the MCAS were just previously incorporated into pilot training. 'All the pilots flying the MAX received the training after the Indonesia crash,' he said.

'There was a directive by Boeing, so they took that training.' Despite following the procedure, the pilots could not recover. Grounded by government regulatorVoluntarily grounded by all operating airlinesEthiopian Airlines grounded its fleet on March 10. The ordered all MAX aircraft grounded in the country on March 11, stating its zero tolerance policy and the similarities of the crashes. Most other regulators and airlines individually grounded their fleets in the next two days.On March 11, the FAA issued a (CANIC) for operators. The CANIC set out the activities the FAA had completed after the Lion Air accident in support of continued operations of the MAX and listed the 59 affected operators of 387 MAX aircraft around the world.On March 13, Canada received new information suggesting similarity between the crashes in Ethiopia and Indonesia.

Canadian Transport Minister informed U.S. Transportation Secretary of his decision to ground the aircraft. Hours later, President Trump announced U.S.

Groundings, following consultation among Chao, acting FAA administrator and Boeing CEO Dennis Muilenburg. The FAA issued an official grounding order, citing the new evidence and acknowledging the 'possibility of a shared cause for the two incidents'. The U.S., Canadian, and Chinese regulators oversee a combined fleet of 196 aircraft, more than half of all 387 airplanes delivered.

Impact on airborne flights Upon groundings About 30 Boeing 737 MAX aircraft were flying in U.S. Airspace when the FAA grounding order was announced. The airplanes were allowed to continue to their destinations and were then grounded.

In Europe, several flights were diverted when grounding orders were issued. For example, an Israel-bound 737 MAX aircraft returned to Stockholm, and two Turkish Airlines MAX aircraft flying to Britain, one to Gatwick Airport south of London and the other to Birmingham, turned around and flew back to Turkey.Upon groundings, the MAX was operated on 8,600 weekly flights. During groundings On June 11, Flight DY8922 attempted a from to.

Such flights can only be flown by pilots meeting a certain (EASA) qualification, and with no other cabin crew or passengers. The contained specific parameters to avoid MCAS intervention, flying at lower than normal with extended, and autopilot on.

However, the aircraft was refused entry into German airspace, and to, France.In a rare exemption, Transport Canada approved 11 flights in August and September, partly to maintain the qualifications of senior Air Canada training pilots, because the airline has no earlier-generation 737s within its fleet. The airline used the MAX during planned maintenance movements, and ultimately flew it to in Arizona for storage.To prepare for ferry flights of its five MAX 8s for winter storage in the milder climate of, France, Icelandair pilots trained in a flight simulator. Scheduled for early October, the aircraft will have the wing flaps out as little as possible and will fly at a lower than usual speed and at an altitude not exceeding 20,000 feet, resulting in the flights taking two hours longer than normal.

The demanded that the flights avoid urban areas. Regulators. Covers the and the members. Taiwan CAA announced airspace closures similar to Japan, stating that the FAA grounding would affect all operators. March 11.

China: The orders all domestic airlines to suspend operations of all 737 MAX 8 aircraft by 18:00 local time (10:00 GMT), pending the results of the investigation, thus grounding all 96 Boeing 737 MAX planes (c. 25% of all delivered) in China. United States: The FAA issued an affirmation of the continued airworthiness of the 737 MAX. As many airlines and regulators began grounding the MAX, the FAA issued a 'continued airworthiness notification', stating that it had no evidence from the crashes to justify regulatory action against the aircraft.

Indonesia: Nine hours after China's grounding, the issued a temporary suspension on the operation of all eleven 737 MAX 8 aircraft in Indonesia. A nationwide inspection on the type was expected to take place on March 12 to 'ensure that aircraft operating in Indonesia are in an airworthy condition'. Mongolia: (MCAA) said in a statement 'MCAA has temporarily stopped the 737 MAX flight operated by from March 11, 2019.' — Paytrick Ky, director. Canada: said it was premature to consider groundings and that, 'If I had to fly somewhere on that type of aircraft today, I would.' . Australia: The banned Boeing 737 MAX from Australian airspace.

Malaysia: The suspended the operations of the Boeing 737 Max 8 aircraft flying to or from Malaysia and transiting in Malaysia. March 13. Canada:, prompted by receipt of new information, said 'There can't be any MAX 8 or MAX 9 flying into, out of or across Canada', effectively grounding all 737 MAX aircraft in Canadian airspace. United States: announced on March 13, that United States authorities would ground all 737 MAX 8 and MAX 9 aircraft in the United States. After the President's announcement, the FAA officially ordered the grounding of all 737 MAX 8 and 9 operated by U.S.

Airlines or in the United States airspace. See also:After the Ethiopian Airlines crash, some airlines proactively grounded their fleets and regulatory bodies grounded the others. (This list includes MAX aircraft that have powered on their, but may not yet have been delivered to an airline. Some pre-delivered aircraft are located at, and airports). The tracking data of Lion Air Flight 610 from Flightradar24The (MCAS) was introduced on the 737 MAX to mitigate the aircraft's tendency to because of the aerodynamic effect of its larger, and heavier, and more powerful CFM and nacelles. The stated goal of MCAS, according to Boeing, was to make the 737 MAX perform similarly to its immediate predecessor, the. The FAA and Boeing both refuted media reports describing MCAS as an system, which Boeing asserted it is distinctly not.

The aircraft had to perform well in a low-speed stall test.Investigators suspect that MCAS was triggered by falsely high (AoA) inputs, as if the plane had up excessively. On both flights, shortly after takeoff, MCAS repeatedly actuated the motor to push down the airplane nose. For the flights, and, showed that the planes struggled to gain altitude. Pilots reported difficulty controlling the airplane and asked to return to the airport. On April 4, 2019 Boeing publicly acknowledged that MCAS played a role in both accidents.After the Lion Air crash, Boeing told airlines that MCAS could not be overcome by pulling back on the control column to stop a runaway trim as on previous generation 737s. Nevertheless, confusion continued: the safety committee of a major U.S.

Airline misled its pilots by telling that the MCAS could be overcome by 'applying opposite control-column input to activate the column cutout switches'. Former pilot and aviation & safety expert testified, 'The logic was that when MCAS was activated, it had to be, and must not be prevented.' On March 11, 2019, after China had grounded the aircraft, Boeing published some details of new system requirements for the MCAS software and for the cockpit displays, which it began implementing in the wake of the prior accident five months earlier:.

If the two AOA sensors disagree with the flaps retracted, MCAS will not activate and an indicator will alert the pilots. If MCAS is activated in non-normal conditions, it will only 'provide one input for each elevated AOA event.' .

Flight crew will be able to counteract MCAS by pulling back on the column.On March 27, Daniel Elwell, the acting administrator of the (FAA), testified before the Senate Committee on Commerce, Science, and Transportation, saying that on January 21, 'Boeing submitted a proposed MCAS software enhancement to the FAA for certification. The FAA has tested this enhancement to the 737 MAX flight control system in both the simulator and the aircraft. The testing, which was conducted by FAA flight test engineers and flight test pilots, included aerodynamic stall situations and recovery procedures.' After a series of delays, the updated MCAS software was released to the FAA in May 2019.

On May 16, Boeing announced that the completed software update was awaiting approval from the FAA. The flight software underwent 360 hours of testing on 207 flights.

Boeing also updated existing crew procedures. The implementation of MCAS has been found to disrupt autopilot operations. Angle of attack sensor system architecture The sensors measure an aircraft's pitch relative to oncoming winds. Though there are two sensors, only one of them is used at a time to trigger MCAS activation on the 737 MAX. The angle of attack system is not robust to the AoA sensor, thus activating MCAS under a single point of failure. Redundancy is a technique that may be used to achieve the quantitative safety requirements per recognized development practices of aircraft systems, such as. The sensors themselves are under scrutiny.

Sensors on the Lion air aircraft were supplied by United Technologies' Rosemount Aerospace. A company based in Florida, XTRA Aerospace Inc., had worked on the 737 MAX AoA sensor of the Lion Air accident.The (USAF) has tankers on order, which is based on a. MCAS, as designed on the KC-46, compares both sensors, and allows pilots to retake control of the airplane.In September 2019, the (EASA) said it prefers triple-redundant Angle of Attack sensors rather than the dual redundancy in Boeing's proposed upgrade to the MAX. Installation of a third sensor could be expensive and take a long time. The change, if mandated, could be extended to thousands of older model 737s in service around the world. Angle of attack display.

This section may be in need of reorganization to comply with Wikipedia's. Please help by to make improvements to the overall structure. ( August 2019) The (DOT) opened an investigation into FAA approval of the Boeing 737 MAX aircraft series, focusing on potential failures in the. The day after the Ethiopian Airlines crash, a issued a on behalf of the for documents related to development of the 737 MAX. On March 19, 2019, the U.S.

Requested the to conduct an audit on the 737 MAX certification process. The has joined the criminal investigation into the certification as well. FBI agents reportedly visited the homes of Boeing employees in.On July 17, representatives of crash victims' families, in testimony to the House Transportation and Infrastructure Committee Aviation Subcommittee, called on regulators to re-certificate the MAX as a completely new aircraft. They also called for wider reforms to the certification process, and asked the committee to grant protective subpoenas so that whistle-blowers could testify even if they had agreed to a as a condition of a settlement with Boeing.In a July 31 senate hearing, the FAA defended its administrative actions following the Lion Air accident, noting that standard protocol in ongoing crash investigations limited the information that could be provided in the airworthiness directive. The agency had recognized that pilot actions played a significant role in the Lion Air accident, and did not dispute that FAA officials believed a recurrence of MCAS malfunction was likely, as reported by.Boeing's former Chief Technical pilot Mark Forkner has invoked the Fifth Amendment right against self-incrimination, to avoid submitting documents to federal prosecutors investigating the crashes. On October 17, Boeing turned over some 10 pages of Forkner's correspondence showing concern with MCAS operation in 2016. The next day, FAA Administrator Dickson, in a strongly worded letter, ordered Muilenburg to give an 'immediate' explanation for delaying disclosure of these documents for months.

Congress In March 2019, announced an investigation into the FAA approval process.Members of Congress and government investigators expressed concern about FAA rules that allowed Boeing to extensively 'self-certify' aircraft. FAA acting Administrator Daniel Elwell said 'We do not allow self-certification of any kind'.In September, a U.S.

Congress panel asked Boeing's CEO to make several employees available for interviews, to complement the documents and the senior management perspective already provided.In September 2019, frustration with Boeing is mounting in Washington, and in the FAA and in international regulators. Representative Peter DeFazio, Chair of the House Committee on Transportation and Infrastructure, said Boeing declined his invitation to testify at a House hearing.

'Next time, it won't just be an invitation, if necessary,' he said. Hearings on October 29 and 30 will be the first time that Boeing executives address Congress about the MAX accidents. In September, U.S. House Transportation and Infrastructure Committee announced that Boeing CEO Muilenburg will testify before Congress accompanied by John Hamilton, chief engineer of Boeing's Commercial Airplanes division and Jennifer Henderson, 737 chief pilot. Hamilton may also appear at the Senate hearing.

The hearings come on the heels of the removal of Mr. Muilenburg's title as chairman of the Boeing board last week. They are expected to cover everything from the design, certification and marketing of the 737 Max to what happened on the flights that crashed.In October, the House Transportation and Infrastructure Committee asked Boeing to allow a flight deck systems engineer who filed an internal ethics complaint to be interviewed.

Office of Special Counsel investigation On April 2, 2019, after receiving reports from whistle-blowers regarding the training of FAA inspectors who reviewed the 737 MAX type certificate, the Commerce Committee launched a second Congressional investigation; it focuses on FAA training of the inspectors.The FAA provided misleading statements to Congress about the training of its inspectors, most possibly those inspectors that oversaw the Max certification, according to the findings of an investigation released in September. The Office of Special Counsel is an organization investigating whistleblower reports. Its report infers that safety inspectors 'assigned to the 737 Max had not met qualification standards'.The OSC sided with the whistleblower, pointing out that internal FAA reviews had reached the same conclusion. In a letter to President Trump, the OSC found that 16 of 22 FAA pilots conducting safety reviews, some of them assigned to the MAX two years ago, 'lacked proper training and accreditation.' Safety inspectors participate in Flight Standardization Boards, that ensure pilot competency by developing training and experience requirements. FAA policy requires both formal classroom training and on-the-job training for safety inspectors.Special Counsel Henry J.

Kerner wrote in the letter to the President, 'This information specifically concerns the 737 Max and casts serious doubt on the FAA's public statements regarding the competency of agency inspectors who approved pilot qualifications for this aircraft'.In September, disputed the conclusions of the OSC, which found that aviation safety inspectors (ASIs) assigned to the 737-MAX certifications lacked sufficient training requirements. To clarify the facts, lawmakers asked the FAA to provide additional information:We are particularly concerned about the Special Counsel's findings that inconsistencies in training requirements have resulted in the FAA relaxing safety inspector training requirements and thereby adopting 'a position that encourages less qualified, accredited, and trained safety inspectors.' We request that the FAA provide documents confirming that all FAA employees serving on the FSB for the Boeing 737-MAX and the Gulfstream VII had the required foundational training in addition to any other specific training requirements.

Aircraft Flight Control Systems

Joint Authorities Technical Review On April 19, a 'Boeing 737 MAX Flight Control System Joint Authorities Technical Review' (JATR) team was commissioned by the FAA to investigate how it approved MCAS, whether changes need to be made in the FAA's and whether the design of MCAS complies with regulations. On June 1, Ali Bahrami, FAA Associate Administrator for Aviation Safety, chartered the JATR to include representatives from FAA, NASA and the nine s of Australia, Brazil, Canada, China, Europe (EASA), Indonesia, Japan, Singapore and UAE.On September 27, the JATR chair said that FAA's process for certifying new airplanes is not broken, but needs improvements rather than a complete overhaul of the entire system. He added 'This will be the safest airplane out there by the time it has to go through all the hoops and hurdles'.According to the final report, FAA failed to properly review MCAS. About the nature of MCAS, 'the JATR team considers that the STS/MCAS and EFS functions could be considered as stall identification systems or stall protection systems, depending on the natural (unaugmented) stall characteristics of the aircraft'.The report recommends that FAA reviews the jet's stalling characteristics without MCAS and associated system to determine the plane's safety and consequently if a broader design review was needed.' The JATR team identified specific areas related to the evolution of the design of the MCAS where the certification deliverables were not updated during the certification program to reflect the changes to this function within the flight control system. In addition, the design assumptions were not adequately reviewed, updated, or validated; possible flight deck effectswere not evaluated; the SSA and functional hazard assessment (FHA) were not consistently updated; and potential crew workload effects resulting from MCAS design changes were not identified.'

Nor has Boeing carried out a thorough verification by stress-testing of the MCASBoeing exerted 'undue pressures' on Boeing ODA engineering unit members (who had FAA authority to approve design changes). Reactions Aircraft manufacturers Boeing Accidents and grounding. The Boeing 737 MAX 8 aircraft roll-out at Renton factory, December 2015Boeing issued a brief statement after each crash, saying it was 'deeply saddened' by the loss of life and offered its 'heartfelt sympathies to the families and loved ones' of the passengers and crews. It said it was helping with the Lion Air investigation and sending a technical team to assist in the Ethiopia investigation.As non-U.S.

Countries and airlines began grounding the 737 MAX, Boeing stated: 'at this point, based on the information available, we do not have any basis to issue new guidance to operators.' Boeing said 'in light of' the Ethiopian Airlines crash, the company would postpone the scheduled March 13 public roll-out ceremony for the first completed.When the FAA grounded the MAX aircraft on March 13, Boeing stated it 'continues to have full confidence in the safety of the 737 MAX. However, after consultation with the U.S. Federal Aviation Administration (FAA), the U.S. National Transportation Safety Board (NTSB), and aviation authorities and its customers around the world, Boeing has determined — out of an abundance of caution and in order to reassure the flying public of the aircraft's safety — to recommend to the FAA the temporary suspension of operations of the entire global fleet of 737 MAX aircraft.' After the grounding, Boeing suspended 737 MAX deliveries to customers, but continued production at a rate of 52 aircraft per month. In mid-April, the production rate was reduced to 42 aircraft per month.

In May 2019, Boeing reported a 56% drop in plane deliveries year on year. In July 2019, after reporting its financial results, Boeing stated that it would consider further reducing or even shutting down production if the grounding lasts longer than expected. On August 23, Boeing announced that if the FAA clears the aircraft to return to service by October 2019, production would return from 42 aircraft per month to 52 by the end of February, and then climb to 57 per month by summer 2020.On October 11, 2019, Boeing's board ceased Dennis Muilenburg as chairman and replaced him with Dennis Calhoun. Muilenburg himself will continue to run the company as CEO with the goal of getting the Boeing 737 MAX back in service. The decision was taken after the JATR released a report in the same day saying that FAA's 'limited involvement' and 'inadequate awareness' of the automated MCAS safety system 'resulted in an inability of the FAA to provide an independent assessment'. The panel report added that Boeing staff performing the certification were also subject to 'undue pressures.

Which further erodes the level of assurance in this system of delegation'. Investigation feedback Between the Ethiopian accident and US groundings, Boeing stated that upgrades to the MCAS flight control software, cockpit displays, operation manuals and crew training were underway due to findings from the Lion Air crash.Boeing anticipated software deployment in the coming weeks and said the upgrade would be made mandatory by an FAA. The FAA stated it anticipated clearing the software update by March 25, 2019, allowing Boeing to distribute it to the grounded fleets. On April 1, the FAA announced the software upgrade was delayed because more work was necessary.On March 14, Boeing reiterated that pilots can always use manual trim control to override software commands, and that both its Flight Crew Operations Manual and November 6 bulletin offer detailed procedures for handling incorrect angle-of-attack readings.On April 4, 2019, Boeing acknowledged that MCAS played a role in both crashes. His comments came in response to public release of preliminary results of the Ethiopian Airlines accident investigation, which suggested pilots performed the recovery procedure. Muilenburg stated it was 'apparent that in both flights' MCAS activated due to 'erroneous angle of attack information.' He said the MCAS software update and additional training and information for pilots would 'eliminate the possibility of unintended MCAS activation and prevent an MCAS-related accident from ever happening again'.

Boeing reported that 96 test flights were flown with the updated software.In an that took place on April 24, 2019, Muilenburg said the aircraft was properly designed and certificated, and denied that any 'technical slip or gap' existed. He said there were 'actions or actions not taken that contributed to the final outcome'.

On April 29, he claimed that the pilots did not 'completely' follow the procedures that Boeing had outlined. He said Boeing was working to make the airplane even safer.On May 5, Boeing asserted that 'Neither the angle of attack indicator nor the AOA Disagree alert are necessary for the safe operation of the airplane. They provide supplemental information only, and have never been considered safety features on commercial jet transport airplanes.' On May 29, Muilenburg acknowledged that the crashes had damaged the public's trust.Before the June, Muilenburg said, regarding the AoA disagree indicator, that Boeing made 'a mistake in the implementation of the alert' and the company's communication 'was not consistent. And that's unacceptable.' On August 4, 2019, Boeing stated they conducted around 500 test flights with updated software, and reported that one test flight involved multiple altitude changes. Corporate structure and new safety practices Following panel review recommendations, Boeing has strengthened its engineering oversight.

As of August 2019, Muilenburg receives weekly reports of potential safety issues from rank-and-file engineers - thousands will report to chief engineers rather than to separate programs, helping them reach senior management more effectively.On September 2019, reported that Boeing board will call for structural changes after the 737 Max crashes: changing corporate reporting structures, a new safety group, future plane cockpits designed for new pilots with less training. The committee, established in April, did not investigate the Max crashes, but produced the first findings for a reform of Boeing's internal structures since then. It will recommend engineers to report to the chief engineer rather than business management, to avoid pressure from business leaders against engineers who identify safety issues. The committee found that inter-group communication was lacking within engineering and between Seattle offices and corporate headquarters during the certification work. The safety group will ensure information is shared and the certification work is independent. The group will report to senior leadership and a new permanent committee on the board.The board said in September that Boeing should also work with airlines to 're-examine assumptions around flight deck design and operation' and recommend pilot training criteria beyond traditional training programs 'where warranted'. Key positions In July 2019, Boeing announced the retirement of 737 program leader Eric Lindblad, the second person to depart that post in two years.

He held the job less than a year, but was not involved in development of the MAX. His predecessor, Scott Campbell, retired in August 2018, amid late deliveries of 737 MAX engines and other components. Lindblad assumed the role shortly before the program became embattled in two accidents and ongoing groundings. He will be succeeded by Mark Jenks, vice president of the program and previously in charge of the. – In October 2019, on the day the JATR published its report, Boeing announced the separation of the CEO and chairman roles, allowing Muilenburg to focus on getting the MAX back in the air.

The board elected to serve as non-executive chairman; he is an independent lead director, and former boss of GE Aviation and potential Boeing CEO. Boeing has resisted earlier calls from shareholder activists to split the roles.

Current and former employees In May 2019, engineers said that Boeing pushed to limit safety testing to accelerate planes certification, including 737 MAX. FAA said it has 'received no whistleblower complaints or any other reports. Alleging pressure to speed up 737 MAX certification.' Former engineers at Boeing blamed company executives of cost-cutting, over more than a decade, yielding to low morale and reduced engineering staffing, which 'they argue contributed to two recent deadly crashes involving Boeing 737 Max jets.' In June 2019, Boeing's software development practices came under criticism from current and former engineers.

Software development work for the MAX was reportedly complicated by Boeing's decision to outsource work to lower-paid contractors, including Indian companies and, though these contractors did not work on MCAS or the AoA disagree alert. Management pressure to limit changes that might introduce extra time or cost was also highlighted.On October 2, 2019, and reported that a Boeing engineer, Curtis Ewbank, filed an internal complaint alleging that company managers rejected a backup system for determining speed, which might have alerted pilots to problems linked to two deadly crashes of 737 Max. A similar backup system is installed on the larger Boeing 787 jet, but it was rejected for 737 Max because it could increase costs and training requirements for pilots. Ewbank said the backup system could have reduced risks that contributed to two fatal crashes, though he could not be sure that it would have prevented them. He also said in his complaint that Boeing management was more concerned with costs and keeping the Max on schedule than on safety. An attorney representing families of the Ethiopian crash victims will seek sworn evidence from the whistleblower.On October 18, Boeing turned over a discussion from 2016 between two employees which revealed prior issues with the MCAS system.

Co-ordinated Turn Systems10.5 CO-ORDINATED TURN SYSTEMS10.5.1 IntroductionA co-ordinated turn is one in which both the lateral acceleration, a, and thesideslip velocity, v, are zero. In such a turn the lift vector is perpendi&!lar to theaircraft axis OY. Co-ordinated turns reduce adverse sideslip and, therefore, rollhesitation. In such turns, there is minimum coupling of rolling and yawingmotions.

Provided that the side force due to aileron, Y:, and the side force dueto the yaw rate, Y, are both negligible, then zero sideAslip angle (P = 0), zerosideslip velocity (v = P/Uo = O), and zero lateral acceleration (a, = 0) areall equivalent conditions. Sometimes, particularly in early textbook? On flyingtechniques, a co-ordinated turn was assumed to be one in which the lateralacceleration experienced in the cockpit was zero - a condition displayed to pilotsby the turn-and-bank indicator, with its black ball centred between the verticallines. However, this condition is not one which finds much use in AFCS studiessince the acceleration at the cockpit is a function of the distance from theaircraft's c.g. Generally, the acceleration at the pilot's station features in AFCSwork only in relation to ride control systems, which are dealt with in Chapter 12.10.5.2 Conditions Needed for a Co-ordinated TurnFor a body axis system the side force equation is: Y = m ( W- P + UR)Following the development detailed in Section 2.4 of Chapter 2, it can be seenthat the rate of change of sideslip angle can be expressed as in eq.

(2.75), i.e.:If R0 = 0, WdUo = a0and, if a co-ordinated turn is achieved, i.e. If: p =0then:If the aircraft has been trimmed so that olo is zero, then:336 Attitude Control SystemsTherefore, in a co-ordinated turn, the rate of turn develops in proportion to thebank angle, 4. Of course, neither Yv nor YzA is generally zero, nor may they beneglected. Consequently, if p is to be zero, so that eq. (10.35) obtains, a steadydeflection of the ailerons is required to maintain the co-ordinated turn. The valueof aileron deflection required is given by:There are a number of factors which may delay the establishment of a co-ordinated turn. They include the following:1.

Automatic Control Systems Pdf Free

An aileron deflection usually induces a yawing moment.2. The build-up of yaw rate, as a result of any change in bank angle, is delayed by aerodynamic lag.3. The action of the yaw damper, which is commonly fitted to aircraft, tends to reduce any transient yaw rate.As an illustration of how these factors affect the turn, consider an aircraft, such asCHARLIE in Appendix B, in which:NkA 0 (10.37)Whenever a positive roll rate is required i.e. BA 0and N$ 0, it is then evident that the sideforce contributions of the tyres ofthe undercarriage contribute to the damping of the motion during groundroll. However, suppose V represents the ground speed and Vw represents thecomponent of headwind which arises when the aircraft is moving on the runway inthe presence of a wind. Equation (10.79) then becomes:The presence of the headwind now results in the real root of the characteristiccubic being finite, rather than zero, with the possibility of some stability in track.When the headwind is positive, the real root is stable if:Therefore, it can be deduced that N b stabilizes the ground tracking mode whereasN; destabilizes it. A discussion of the dynamics of aircraft rotation and lift-off can be foundin Pinsker (1967).10.8 CONCLUSIONSAutomatic control systems for maintaining the attitude angles of an aircraft, orfor changing an aircraft's attitude to a new commanded value, are introduced.

Toemphasize the principles of negative feedback control which are common to themany varieties of attitude control system used on aircraft, the pitch attitudecontrol system is dealt with extensively. The use of a pre-filter in conjunction withthese types of AFCS to obtain the required handling qualities in the controlledaircraft is briefly dealt with, before a roll angle control system is considered.

Theuse in such systems of phase advance compensation networks, or a roll ratedamper as an inner loop to achieve the required dynamic response is dealt withand gain scheduling as a means of maintaining the same closed loop performanceover as much of the flight envelope as possible is also treated. The unwantedresults of tight roll control, such as roll ratchet or pitching motion due to rolling,are treated briefly before the means of achieving automatically controlled co-ordinated turns by a variety of methods is explained.

The chapter concluded withthe important subject of controlling direction stability during ground roll.10.9 EXERCISES+,10.1 A transport aircraft, flying at a Mach number of 0.8 and a height of 10000 m has as its transfer function, relating bank angle, to aileron deflection, SA, Gl(s) asExercises 353as defined below. When the aircraft flies at half the height and at a Mach numberof 0.4 its transfer function becomes G2(s).The block diagram of the bank angle control system used on the aircraft is shownin Figure 10.24. Controller Aircraft dynamics I m lAttitude gyroFigure 10.24 Block diagram of a bank angle control system for Exercise 10.1.+,(a) Determine the closed loop transfer function relating the bank angle, to +,-the commanded bank angle, for flight condition 1. (Hint: make reasonable simplifying assumptions.)(b) What is the effect upon the dynamic response of the bank angle control system if the aircraft flies at flight condition 2? Assume the controller gain, K+, remains unchanged.(c) If the value of K+ is 2.5, and if the value of the commanded bank angle is 5.0°, sketch the closed loop response for both flight conditions.10.2 If the experimental VTOL aircraft of Exercise 2.7 is flying at 15 m s-l, and has the same stability derivatives that were listed in that question, calculate the lateral acceleration at its c.g. For a flat, co-ordinated turn in which the yaw rate is 0.33 rad s-l.

(The aircraft may be assumed to have zero sideslip velocity.)10.3 In the sideslip suppression system, represented by the block diagram in Figure 10.25 a sideslip signal is used as feedback to drive the rudder so that sideslip is eliminated. The wash-out filter in the inner loop can be regarded as a blocking filter for constant manoeuvre commands, i.e. Yaw rate feedback operates only during changes of the flight state. The dynamics associated with the rudder servo are negligible.