What is the required duration for supporting ultimate loads without failure as per ETSO-C25a's amendment to NAS 806 4.3(c)?

At least 3 seconds, when the ultimate loads are applied separately.

ETSO-C25a

Q: What are the minimum performance standards for aircraft seats and berths covered by ETSO-C25a?

The standards set forth in National Aircraft Standard Specification 806, revised January 1, 1956, as amended and supplemented by ETSO-C25a.

Q: What rearward load must pilot and copilot seats withstand according to ETSO-C25a, and where is it applied?

A rearward load of 450 pounds, applied 8 inches above the intersection of the seat back with the seat bottom.

Q: How is the weight of the seat or berth accounted for in the design ultimate load under ETSO-C25a?

The weight of the seat or berth times the appropriate 'g' value shall be added to the design ultimate load specified in subdivision (i) and in subparagraph 4.1.2 of NAS 806.

Q: Which aircraft seats are subject to the requirements of ETSO-C25a?

Seats used in transport category aircraft for which an application for type certificate was made prior to March 5, 1952, that are manufactured on or after the date of this ETSO.

Navigate / EASA

Ask question Discover more Add to collection

ETSO-C25a

ED Decision 2003/10/RM

Aircraft Seats and Berths (Type I Transport 6g Forward Load)

1 Applicability

This ETSO gives the requirements which seats, used in transport category aircraft for which an application for type certificate was made prior to March 5, 1952, that are manufactured on or after the date of this ETSO must meet in order to be identified with the applicable ETSO marking.

2 Procedures

2.1 General

Applicable procedures are detailed in CS-ETSO Subpart A.

2.2 Specific

None.

3 Technical Conditions

3.1 Basic

3.1.1 Minimum Performance Standard

Standards set forth in National Aircraft Standard Specification 806, revised January 1, 1956, as amended and supplemented by this ETSO:

Exceptions

(i) The ultimate loads corresponding to the aircraft reduced weight gust load factor or the airplane designer’s special requirements may exceed the ultimate down loads for Type I seats specified in subparagraph 4.1.2 of NAS 806. For the purpose of this order, in order to provide for such loading conditions, the ultimate down loads specified in table 1 of 4.1.2 for Type I seats shall be 1,000 pounds (6g) instead of 765 pounds.

(ii) To insure that pilot and copilot seats will provide for the rearwards loads resulting from the application of pilot forces to the flight controls, such seats shall withstand a rearward load of 450 pounds. The load shall be applied 8 inches above the intersection of the seat back with the seat bottom.

(iii) The weight of the seat or berth times the appropriate „g“ value shall be added to the design ultimate load specified in subdivision (i) and in subparagraph 4.1.2 of NAS 806.

(iv) For the purpose of this order, 4.3(c) of NAS 806 should read: „that the structure is capable of supporting without failure for at least 3 seconds the ultimate loads specified in this order when applied separately.“

3.1.2 Environmental Standard None.

3.1.3 Computer Software

None

3.2 Specific

None.

4 Marking

4.1 General

Marking is detailed in CS-ETSO Subpart A paragraph 1.2.

4.2 Specific

None.

5 Availability of Referenced Document

See CS-ETSO Subpart A paragraph 3.

Details

Source-Title: ETSO-C25a View latest amendments

Erulesid: ERULES-1963177438-7229 Compare versions

Domain: Initial airworthiness

Amendedby: Initial issue

Applicabilitydate: 24 October, 2003

Entryintoforcedate: 24 October, 2003

Regulatorysource: ED Decision 2003/10/RM Navigate

Regulatorysubject: CS-ETSO

Typeofcontent: CS (Certification specification)

Origin: EASA

Category: EAR