Method and device for detecting that the design loads of an aircraft have been exceeded

• US 5,511,430 A
• Filed: 11/29/1994
• Issued: 04/30/1996
• Est. Priority Date: 12/06/1993
• Status: Expired due to Term

• Current Assignee: Airbus Operations SAS (Airbus SE)
• Original Assignee: Aerospatiale Societe Nationale Industrielle
• Inventors: Regis, Olivier, Delest, Thierry, Schuster, Patrick
• Primary Examiner(s): Chilcot, Richard
• Assistant Examiner(s): NOORI, MAX H
• Application Number:
  US08/350,082
• Time in Patent Office: 518 Days
• Field of Search: 73/802, 73/178 R, 73/178 T
• US Class Current: 73/802
• CPC Class Codes: G01G 19/07 for weighing aircraft
• CPC Class Codes: G05D 1/0066 for limitation of acceleration or stress

Abstract

The invention relates to a method for detecting that the design loads of an aircraft have been exceeded during landing.

According to the invention:

--in a preliminary step:

the load criteria (C1, C2, . . . , Cp) are defined; and

the laws of variation of the allowable values (C1ad, C2ad, . . . , Cpad) of these load criteria (C1, C2, . . . , Cp) are determined, as a function of input parameters (P1, P2, . . . , Pn); and

--at the moment of landing:

the values of the said input parameters (P1, P2, . . . , Pn) and of the said load criteria (C1, C2, . . . , Cp) are measured;

the allowable values (C1ad, C2ad, . . . , Cpad) of the said load criteria (C1, C2, . . . , Cp) are calculated;

for each of the said load criteria (C1, C2, . . . , Cp), the measured effective value (C1m, C2m, . . . , Cpm) is compared with the calculated allowable value (C1ad, C2ad, . . . , Cpad); and

it is determined whether a structural inspection must be carried out.

Claims

1. Method for detecting that design loads of an aircraft have been exceeded during moment of landing, necessitating a structural inspection of the said aircraft being invoked, comprising:

in a step preliminary to the moment of landing;

defining load criteria (C1, C2, . . . , Cp), which are measurable on ,the aircraft and representative of effective loads to which the aircraft is subjected; and

determining laws of variation of allowable values (C1ad, C2ad, . . . , Cpad) of these load criteria, (C1, C2, . . . , Cp) as a function of input parameters (P1, P2, . . . , Pn) measurable on the aircraft; and

at the moment of landing;

measuring values of the said input parameters (P1, P2, . . . , Pn) and of the said load criteria (C1, C2, . . . , Cp);

calculating, on the basis of the said laws of variation and of the said measured values of the input parameters, allowable values (C1ad, C2ad, . . . , Cpad) of the said load criteria (C1, C2, . . . , Cp);

comprising for each of the said load criteria (C1, C2, . . . , Cp), measured effective value (C1m, C2m, . . . , Cpm) with calculated allowable value (C1ad, C2ad, . . . , Cpad); and

determining, on the basis of the result of the various comparisons, whether a structural inspection has to be carried out.

2. Method according to claim 1, characterized in that, on the basis of the result of the various comparisons, the type of structural inspection to be carried out is determined as appropriate.

3. Method according to claim 2, characterized in that, according to the type of structural inspection to be carried out, one or more of the following parts of the aircraft are checked:

the nose landing gear, the main landing gear, the central landing gear, the wings, the fuselage and the engine pylons.

4. Method according to claim 1, characterized in that, in order to determine the law of variation of the allowable values (Ciad) of a load criterion (Ci) as a function of an input parameter (Pi), the corresponding allowable value (Ciad) of the load criterion is sought for various values of the said input parameter (Pi), by carrying out the following steps, for each of the said various values of the input parameter:

a) an assumed value of the load criterion is chosen;

b) the said assumed value of the load criterion and the said value of the input parameter are inserted into a landing model;

c) with the aid of this landing model, the effective loads to which the aircraft is subjected are determined;

d) these effective loads determined are compared with the design limit loads; and

e) if the said loads are equal, the said assumed value of the load criterion is defined as allowable value, corresponding to the said value of the input parameter;

otherwise, steps a) to e) are repeated, choosing a different assumed value of the load criterion.

5. Method according to claim 4, characterized in that the law of variation of the allowable values (Ciad) of a load criterion (Ci), as a function of an input parameter (Pi), is of the form

6. Method according to claim 4, characterized in that, in order to determine the law of variation of the allowable values (Cjad) of a load criterion (Cj), as a function of several input parameters (P1, P2, . . . , Pn), the corresponding allowable value (Cjad) of the load criterion (Cj) is sought for different combinations of values of the said input parameters (P1, P2, . . . , Pn), by carrying out the said steps a) to e), for each of the said combinations, for which the chosen values of all the said input parameters (P1, P2, . . . , Pm) are input each time into the landing model.

7. Method according to claim 6, characterized in that the law of variation of the allowable values (Cjad) of a load criterion (Cj), as a function of input parameters (P1, P2, . . . , Pn), is of the form

8. Method according to claim 1, characterized in that, as input parameters (P1, P2, . . . , Pn), at least some of the said following parameters are used:

the mass of the aircraft, the centre of gravity of the aircraft, the acceleration at the moment of landing, the maximum acceleration recorded in the course of the landing, the attitude of the aircraft, the roll-off speed and the roll speed.

9. Method according to claim 1, characterized in that, as load criteria (C1, C2, . . . , Cp), at least some of the said following criteria are used:

the vertical speed, the vertical acceleration, the lateral acceleration and the vertical load on the nose gear.

10. Device (1) for implementing the method specified under one of claims 1 to 9, characterized in that it includes:

--a first set (E1) of sensors (D1, D2, . . . , Dn) intended to measure the values of the said input parameters (P1, P2, . . . , Pn);

--a second set (E2) of sensors (F1, F2, . . . , Fp) intended to measure the values (C1m, C2m, . . . , Cpm) of the said load criteria (C1, C2, . . . , Cp);

--a computer (CAL) linked to the said first set (E1) of sensors, including the laws of variation of the allowable values of the load criteria, receiving the measured values of the input parameters (P1, P2, . . . , Pn) and determining the corresponding allowable values (C1ad, C2ad, . . . , Cpad) of the load criteria (C1, C2, . . . , Cp); and

--a comparison device (DC), linked to the said second set (E2) of sensors and to the said computer (CAL), comparing the measured effective value (C1m, C2m, . . . , Cpm), for each load criterion (C1, C2, . . . , Cp), with the calculated allowable value (C1ad, C2ad, . . . , Cpad), determining, from the said comparisons, whether a structural inspection has to be carried out and communicating the type of structural inspection to be carried out, as appropriate.