OPTIMIZED TRAJECTORY TO NOISE IMPROVEMENT WITH AUTO-TAKEOFF

Abstract

Aircraft takeoff trajectory is automatically optimized to minimize Perceived Noise Level. A flight computer automatically performs all the actions to takeoff the airplane and assure that its real takeoff trajectory is compliant with the takeoff trajectory optimized. Variability of trajectory is eliminated through automation of pilot's actions during takeoff and assurance of an optimum trajectory. The system also provides for simultaneity of actions and the changing of aerodynamic configuration during takeoff.

Claims

1. A system for automatic consistent noise abatement takeoff of an aircraft comprising: at least one sensor; and at least one processor operatively coupled to the at least one sensor, the at least one processor being configured to perform the following: (a) determine when the aircraft reaches rotation velocity VR and automatically control the aircraft to rotate exactly at the rotation velocity VR; (b) monitor the attitude of the aircraft and automatically control the aircraft to attain and maintain a takeoff pitch angle ? and pitch rate q optimized for noise abatement; and (c) monitor the altitude of the aircraft and automatically control the aircraft to cutback on thrust during climb at a predetermined altitude HCUT to abate noise.

2. The system of claim 1 wherein the at least one sensor comprises an inertial sensor and an anemometric sensor.

3. The system of claim 1 wherein the at least one processor is further configured to automatically control the aircraft to restore thrust once a restoration altitude HR is attained.

4. The system of claim 1 wherein the automation of takeoff procedures brings the possibility of simultaneity of actions and the aerodynamic configuration changes during takeoff climb so that as a consequence, the optimized trajectory of the aircraft will result in even lower perceived noise levels than the perceived noise level for an optimum trajectory based on non-simultaneous procedures.

5. The system of claim 1 wherein said control is transparent to the pilot such that the pilot does not need to perform any procedure, except for setting up the function for perceived noise optimization, to thereby reduce the pilot workload in a very demanding flight phase, as well as produce a more consistent operation.

6. A system for automatic consistent takeoff noise reduction of an aircraft comprising: at least one sensor; and at least one processor operatively coupled to the at least one sensor, the at least one processor being configured to perform the following: (a) determine when the aircraft reaches rotation velocity VR and automatically control the aircraft to rotate exactly at the rotation velocity VR; (b) monitor the trajectory of the aircraft; (c) in response to the monitoring, control the trajectory according to an optimized noise reducing trajectory; and (d) in response to the monitoring, upon the achievement of a predefined, optimized point in the trajectory, perform a thrust cutback procedure thus abating noise.

7. A system for automatic consistent takeoff noise reduction of an aircraft comprising: at least one sensor; and at least one processor operatively coupled to the at least one sensor, the at least one processor being configured to perform the following: (a) determine when the aircraft reaches rotation velocity VR and automatically control the aircraft to rotate exactly at the rotation velocity VR; (b) monitor the trajectory of the aircraft; (c) in response to the monitoring, control the trajectory according to an optimized noise reducing trajectory; and (d) in response to the monitoring, perform an optimal thrust management automatically in order to obtain noise abatement.

8. A method for automatic consistent noise abatement takeoff of an aircraft comprising: measuring with at least one sensor; in response to the measuring, determining when the aircraft reaches rotation velocity VR and automatically controlling the aircraft to rotate exactly at the rotation velocity VR; in response to the measuring, monitoring the attitude of the aircraft and automatically controlling the aircraft to attain and maintain a takeoff pitch angle and pitch rate optimized for noise abatement; and in response to the measuring, monitoring the altitude of the aircraft and automatically controlling the aircraft to cutback on thrust during climb to a predetermined altitude HR to abate noise.

9. An aircraft comprising: engines; control surfaces; a pitch guidance subsystem that generates pitch angle, pitch target and rotation trigger information; and a pitch control subsystem operatively coupled to at least the control surfaces and the pitch guidance subsystem, the pitch control subsystem being structured to receive the pitch angle, pitch target and rotation trigger information from the pitch guidance subsystem and perform noise-abatement takeoff calculations to provide the aircraft with capability to calculate and, with an automatic takeoff option, to automatically control the control surfaces so the aircraft follows noise-abatement takeoff pitch guidance as a function of the actual takeoff radiant constrained by any applicable aircraft geometric limitations.

10. The aircraft of claim 9 wherein in response to measuring aircraft pitch, the pitch control subsystem determines when the aircraft reaches rotation velocity VR and automatically controls the aircraft to rotate exactly at the rotation velocity VR.

11. The aircraft of claim 9 wherein the pitch control subsystem is configured to monitor the attitude of the aircraft and automatically controls the aircraft to attain and maintain a takeoff pitch angle and pitch rate optimized for noise abatement.

12. The aircraft of claim 9 wherein the pitch control subsystem is configured to monitor the altitude of the aircraft and automatically control the engines to cut back on thrust during climb to a predetermined altitude to abate noise.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The following detailed description of exemplary non-limiting illustrative embodiments is to be read in conjunction with the drawings of which:

[0026] FIG. 1 shows delayed rotation effect: when the rotation is delayed, the aircraft flies over the microphones at a lower altitude and, consequently, the microphones detect higher noise.

[0027] FIG. 2 shows takeoff flightpaths at London City Airport: although there is a very detailed and clear procedure for reduction of perceived noise level during takeoff, the real flightpaths show that during operation is very difficult to maintain consistency with this procedure.

[0028] FIG. 3a shows comparison between real data and optimum data of V.sub.R: this figure shows that there is a dispersion of 10 kts in terms of V.sub.R.

[0029] FIG. 3b shows comparison between real data and optimum data of pitch rate q: the real data shows that the pilots consistently perform the rotation of the airplane below the recommended pitch rate.

[0030] FIG. 3c shows comparison between real data and optimum data of pitch ?: there is clearly a lack of operational consistency in terms of pitch, which brings a penalty in terms of Perceived Noise Level when the aircraft is flying over the microphones.

[0031] FIGS. 4a and 4b show pitch rate effect in perceived noise level: if the rotation is performed one degree per second below the recomended pitch rate, there is a penalty of almost 2 dB in terms of Perceived Noise Level.

[0032] FIG. 5 shows an example non-limiting control system.

[0033] FIG. 6 shows an example non-limiting parameter development.

[0034] FIG. 7 shows a schematic of an example non-limiting data evaluation and system decision process.

DETAILED DESCRIPTION OF EXAMPLE NON-LIMITING EMBODIMENTS

[0035] Example non-limiting embodiments provide method and apparatus to optimize the takeoff trajectory to minimize Perceived Noise Level and a system to automatically perform all the actions to takeoff the airplane and assure that its real takeoff trajectory is compliant with the takeoff trajectory optimized. Such example non-limiting embodiments eliminate variability of trajectory through automation of pilot's actions during takeoff and assurance of an optimum trajectory. Example non-limiting embodiments also provide for simultaneity of actions and the changing of aerodynamic configuration during takeoff

[0036] Example Non-Limiting System Architecture

[0037] FIG. 5 shows an overview of an example non-limiting auto-takeoff system and the interfaces with other aircraft systems. As shown in FIG. 5, an aircraft 100 includes conventional sensors and voting arrays 102 that monitor parameters such as temperature, pressure altitude, speed, height and pitch angle and provide sensed (voted) values to pitch guidance subsystem 104. The sensor/voting array 102 is thus capable of measuring the response of the aircraft to control inputs from flight control system 106 such as elevator position. The pitch guidance subsystem 104 also receives pilot input 108 including V.sub.R, weight and Ni. Additionally, the pitch guidance subsystem 104 receives landing gear and flap information from a configuration subsystem 110. Pitch guidance subsystem 104 thus obtains information from aircraft sensors 102 and pilot input 108 devices, while the output of the auto-takeoff system is transmitted to the flight control system 106. For a pitch guidance indication, the pitch target is transmitted also to the aircraft display 112.

[0038] Pitch control subsystem 114 receives pitch angle, pitch target and rotation trigger information from pitch guidance subsystem 104. The pitch control subsystem 114 applies noise-optimized takeoff calculations to provide the aircraft with capability to calculate and, with an automatic takeoff option, to follow an optimum takeoff pitch guidance as a function of the actual takeoff radiant (in the conditions considered for dispatch) constrained by the aircraft geometric limitations, if applicable.

[0039] Pitch guidance subsystem 104 and pitch control subsystem 114 may each comprise at least one processor coupled to non-transitory storing instructions the processor executes to perform program controlled operations such as shown in FIG. 7. Other implementations such as hardware, hybrid hardware and software, application specific integrated circuit, etc., are also possible.

[0040] In one example non-limiting embodiment, the pitch guidance subsystem 104 uses the estimated weight, weather parameters (temperature and wind) and airport data (runway information) to calculate the related thrust and V-speeds. With parameter inputs (weight, thrust, takeoff configurationflaps positionand V-speeds), an optimum pitch rate and/or an optimum pitch is/are calculated to provide the optimum trajectory after lift-off, as well as, an optimum altitude for cutback and for thrust restoration are provided, when appropriate. In some embodiments, the FIG. 5 control system includes additional outputs used to directly control such jet engine thrust cutback and restoration.

[0041] FIG. 6 shows an example non-limiting multi-stage processing performed by the FIG. 5 control system. In FIG. 6, block 202 indicates the control system being programmed with optimal parameters such as optimal pitch rate (q.sub.OPT), optimal pitch (?.sub.OPT), optimal thrust cutback height (H.sub.CUT), and optimal thrust restoration height (H.sub.R) after thrust cutback. The control system uses a GPS (geo-positioning system) to determine V speeds such as rotation speed V.sub.R (block 204). The control system uses inertial sensors (e.g., gyrosensors, accelerometers, etc.) to determine aircraft takeoff configuration (block 206). The control system uses external sensors such as wind (anemometric) sensors to determine weather conditions including wind speed (block 208). The control system uses all of these parameters to control thrust cutback and restoration (block 210).

[0042] FIG. 7 shows how with these parameters calculated, the control system will start controlling the takeoff procedures after the brakes are released (block 302) and will perform the following actions: [0043] Runway acceleration is determined and controlled based on parameters including takeoff configuration 306, thrust 308, VSPEEDS 310 and the initial parameters described in block 202 above, based on weight, weather information and runway information (blocks 304-314); [0044] The Speed is monitored (e.g., first by a GPS system and then by an anemometric sensor 316 when the aircraft has acquired sufficient velocity for the anemometric system to function) until the speed reaches the V.sub.R value (decision block 318); [0045] When Speed=V.sub.R, the airplane is immediately rotated (e.g., by controlling the control surfaces) with optimum pitch rate q=q.sub.OPT (block 320); [0046] Pitch ? is monitored using inertial sensors 322 until it reaches optimum pitch value ?.sub.OPT (block 324); [0047] Optimum pitch ?.sub.OPT is captured and maintained (the control system controls the surface controls while monitoring aircraft attitude via the inertial sensors to maintain optimum pitch angle and pitch rate); [0048] The aircraft is controlled to climb at optimum pitch and pitch rate (block 326); [0049] Altitude is monitored (e.g., by GPS or other altitude sensor in block 328) until the aircraft reaches an optimum altitude for thrust cutback (H=H.sub.CUT) (block 330); [0050] Cutback of thrust is performed for noise abatement, by the control system automatically controlling the jet engines to reduce thrust and slow climb once a safe altitude has been reached to do so (block 334); [0051] Altitude continues to be monitored until the aircraft reaches an optimum altitude for thrust restoration (H=H.sub.R) (block 332) (i.e., once the control system determines the aircraft has climbed to a sufficient altitude such that thrust cutback for noise abatement purposes is no longer needed, it may control the engines to restore increased thrust); [0052] Thrust is restored to Climb Thrust (block 336).

[0053] The entire process is transparent to the pilot. The pilot does not need to perform any procedure, except for setting up the function for perceived noise optimization. This will reduce the pilot workload in a very demanding flight phase, as well as produce a more consistent operation.

[0054] Besides that, the automation of takeoff procedures brings the possibility of simultaneity of actions and the aerodynamic configuration changes during takeoff climb. As a consequence, the optimized trajectory will result in even lower perceived noise levels than the perceived noise level for an optimum trajectory based on non-simultaneous procedures.

[0055] The simultaneity of some actions like rotating the airplane exactly at V.sub.R with a pitch rate at or above 5 deg/s and capturing pitch at or above 18 deg would bring substantial improvement to the optimum trajectory for Perceived Noise Level in Flyover.

[0056] While the invention has been described in connection with what is presently considered to be the most practical and preferred embodiments, it is to be understood that the invention is not to be limited to the disclosed embodiments, but on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.