Apparatus and methods for controlling aircraft thrust during a climb

• US 5,299,765 A
• Filed: 12/23/1991
• Issued: 04/05/1994
• Est. Priority Date: 12/23/1991
• Status: Expired due to Term

• Current Assignee: The Boeing Co.
• Original Assignee: The Boeing Co.
• Inventors: Blechen, Frederick C.
• Primary Examiner(s): Huppert, Michael S.
• Assistant Examiner(s): BIDWELL, ANNE
• Application Number:
  US07/811,724
• Time in Patent Office: 834 Days
• Field of Search: 244/178, 244/180, 244/182, 244/186, 244/188, 244/194, 244/195, 364/427, 364/431.01, 364/433
• US Class Current: 244/182
• CPC Class Codes: G05D 1/0661 specially adapted for take-off

Abstract

A controller for automatically controlling aircraft thrust during a noise abatement climb operates so as to smoothly reduce aircraft thrust during a reduction in aircraft climb angle at the noise abatement altitude so as to maintain a selected noise abatement climb gradient dependent upon the pilot maintaining a recommended climb airspeed. The selected noise abatement climb gradient is compared with a measured climb gradient to generate an error term. The measured climb gradient is adjusted by a acceleration correction term in order to make the resulting measured climb gradient term independent of airspeed changes. The climb gradient error term is added to the selected climb gradient to generate a commanded climb gradient which is converted to an equivalent thrust (noise abatement thrust). The resulting noise abatement thrust is compared with measured engine thrust to generate an error term for controlling engine thrust so that the aircraft follows the noise abatement climb gradient.

Claims

1. Method for adjusting aircraft engine thrust, the method comprising the steps of:

a. selecting a climb gradient for climbing the aircraft;

b. flying the aircraft at a first climb attitude during a first climb segment;

c. reducing a climb attitude of the aircraft at an end of the first climb segment from the first climb attitude;

d. flying the aircraft at a selected airspeed during a second climb segment;

e. measuring a climb gradient of the aircraft;

f. determining a reference thrust level by (1) determining a first value which is a function of the selected climb gradient. (2) determining a second value which is independent of aircraft airspeed changes by determining an acceleration value of the aircraft and combining the acceleration value and the measured climb gradient, (3) determining a difference between the first value and the second value to generate and error value, and (4) converting the error value to a reference thrust level;

g. sensing an actual thrust level of the engine; and

h. adjusting the actual thrust level of the engine so that the actual thrust level approaches the reference thrust level during the climb attitude reduction so that the aircraft climbs at the selected climb gradient during the second climb segment.

2. The method as set forth in claim 1 additionally comprising the step of flying the aircraft at the selected airspeed during the first climb segment.

3. The method as set forth in claim 1 wherein the selected climb gradient is a noise abatement climb gradient.

4. The method as set forth in claim 1 wherein the step of converting the error value to the reference thrust level includes the steps of:

a. combining the error value with the first value to generate a third value;

b. multiplying the third value by a value which is a function of a coefficient of lift value for the aircraft so as to generate a fourth value;

c. multiplying the fourth value by a fifth value; and

d. combining the fifth value with a value which is a function of a coefficient of drag value for the aircraft.

5. The method as set forth in claim 1 wherein the reference thrust level determining step includes the steps of:

a. determining a minimum climb gradient value; and

b. comparing the minimum climb gradient value with the thrust level value and selecting one of the two values which is largest so as to generate the reference thrust level.

6. Apparatus for adjusting aircraft engine thrust, the apparatus comprising:

a. means for selecting a climb gradient for climbing the aircraft;

b. means for flying the aircraft at a first climb attitude during a first climb segment;

c. means for reducing a climb attitude of the aircraft at an end of the first climb segment from the first climb attitude;

d. means for flying the aircraft at a selected airspeed during a second climb segment;

e. means for measuring a climb gradient of the aircraft;

f. means for determining a reference thrust level including (1) means for determining a first value which is a function of the selected climb gradient, (2) means for determining a second value which is independent of aircraft airspeed changes by determining an acceleration value of the aircraft and combining the acceleration value and the measured climb gradient, (3) means for determining a difference between the first value and the second value to generate an error value, and (4) means for converting the error value to a reference thrust level;

g. means for sensing an actual thrust level of the engine; and

h. means for adjusting the actual thrust level of the engine so that the actual thrust level approaches the reference thrust level during the climb attitude reduction so that the aircraft climbs at the selected climb gradient during the second climb segment.

7. The apparatus as set forth in claim 6 additionally comprising means for flying the aircraft at the selected airspeed during the first climb segment.

8. A method for adjusting aircraft engine thrust, the method comprising the steps of:

a. selecting a climb gradient for climbing the aircraft;

b. flying the aircraft at a first climb attitude during a first climb segment;

c. reducing a climb attitude of the aircraft at an end of the first climb segment from the first climb attitude;

d. flying the aircraft at a selected airspeed during a second climb segment;

e. determining a climb thrust level which is a function of the selected climb gradient;

f. determining a minimum climb gradient level;

g. comparing the minimum climb gradient level with the climb thrust level and selecting one of the two such levels which is largest so as to generate a reference thrust level;

h. sensing an actual thrust level of the engine; and

i. adjusting the actual thrust level of the engine so that the actual thrust level approaches the reference thrust level.

9. Apparatus for adjusting aircraft engine thrust, the method comprising the steps of:

a. means for selecting a climb gradient for climbing the aircraft;

b. means for flying the aircraft at a first climb attitude during a first climb segment;

c. means for reducing a climb attitude of the aircraft at an end of the first climb segment from the first climb attitude;

d. means for flying the aircraft at a selected airspeed during a second climb segment;

e. means for determining a climb thrust level which is a function of the selected climb gradient;

f. means for determining a minimum climb gradient level;

g. means for comparing the minimum climb gradient level with the climb thrust level and selecting one of the two such levels which is largest so as to generate a reference thrust level;

h. means for sensing an actual thrust level of the engine; and

i. means for adjusting the actual thrust level of the engine so that the actual thrust level approaches the reference thrust level.