Federal Department of the Environment, Transport, Energy and

Communications DETEC

Federal Office of Civil Aviation FOCA
Safety Division

- Aircraft

Lufttüchtigke itsanweisung (LTA) Consigne de Navigabilité (CN)

Direttive sulla N avig abilità (DN ) Airworthiness Directive (AD) FOCA AD



## HB

- 20 1 4

- 001

Inkraftsetzung Mise en vigue u r Entrata in vigore

Effective Date 08 August 2 0 14 

### Pilatus

– PC

- 7

FOCA TC/TCDS No: F 56

- 20

1 / 2

Rechtsgrundlage: Art. 26, 51 und 51A (Verordnung über die Lufttüchtigkeit von Luftfahrzeugen: SR 748.215.1) Base juridique: Art. 26, 51 et 51A ( Ordonnance sur la navigabilité des aéronefs: SR 748.215.1) Base giuridica: Art. 26, 51 e 51A ( Ordinanza concernente la navigabilità degli aeromobili: SR 748.215.1) Legal base: Art. 26, 51 and 51A ( Ordinance on the airworthiness of aircraft: SR 748.215.1) Issue D ate: 25 July 20 1 4

ATA Chapter : ATA 51

– Standard Practices and Structures

Su bject: Standard Practices and Structures

– Aircraft Structure

– Identific a tion of Material Specification, Inspection

Su persedure / R e vi sed AD(s): Not applica ble

Type Certificate

Holder’s Name: Pilatus Aircraft Ltd.

Manufacturer(s): Pilatus Aircraft Ltd.

Applicability: Model PC

- 7 aircraft, Manufacturer Serial Numbers (MSN) 101 through

MSN 618

.

Reason: This Airworthiness Directive (AD) is prompte d due to the possibility of cracks in some critical parts. It is possible that stress corrosion cracks

may occur on various parts of the aircraft structure initially made of al umi n ium alloy AA2024

- T351 which is susceptible to Stress Corrosion Cracking (SCC ). Later in production, the material specification was changed to al u minium alloy AA2124

- T851 to decrease the risk of stress corrosion. The Part Number (P / N) of the affected structural parts are not always changed when the new material was introduced.

Suc h a condition, if left uncorrected, could lead to failure of critical parts on the aircraft structure and will prejudice the structural integrity of the

aircraft.

In order to correct and control the situation, this AD requires a one

- time check to identify the material specification and inspect the affected areas of the airframe that are made of aluminium alloy AA2024

- T351. Any stru ctural parts of the aircraft structure found to be cracked must be reported to Pilatus prior to further flight.

Required A c tion(s) and Compliance Time(s): Required as indicated below, unless already accomplished , within the next 365 days after the effective date of this AD :

(1) P erform a one time conductivity test of items 6 thru 9 and 11 thru 13 (both on aircraft and those held in stores) as listed in p ara graph (§)

. 1.A.(2) of PILATUS PC

- 7 Service Bulletin No. 51

- 001, to check the material of the parts.Lufttüchtigkeitsanweisung (LTA) Consigne de Navigabilité (CN) Direttive sulla Navigabilità ( DN )

Airworthin ess Directive (AD) FOCA AD



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- 20 1 4

- 001

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Rechtsgrundlage: Art. 26, 51 und 51A (Verordnung über die Lufttüchtigkeit von Luftfahrzeugen: SR 748.215.1) Base juridique: Art. 26, 51 et 51A ( Ordonnance sur la navigabilité des aéron efs: SR 748.215.1) Base giuridica: Art. 26, 51 e 51A ( Ordinanza concernente la navigabilità degli aeromobili: SR 748.215.1) Legal base: Art. 26, 51 and 51A ( Ordinance on the airworthiness of aircraft: SR 748.215.1) (2) If the parts are made of aluminium alloy AA2124

- T851, make an entry in the aircraft logbook as required by § 3.D.(3) of PILAT US PC

- 7 Se rvice Bulletin No. 51

- 001

.

(3) Because it is difficult to inspect for cracks on the elevator center co ntrol

- rods (Item 3 as listed in § 1.A.(2) of PILATUS PC

- 7 Service Bull etin No. 51

- 001 ), these type of control rods will be r e placed.

(4) Parts (Items 1, 2, 4, 5 and 10 as listed in § 1.A.(2) of PIL A TUS PC

- 7
Service Bulletin No. 51

- 001 ) are made of aluminium alloy AA2024

- T351. Therefore:

• Do a one time inspection for cracks of Items 1, 2, 4 and 10

• Replace Item 5

(5) If the conductivity test shows the parts a re made of aluminium alloy

AA2024

- T351:

a) For Items 7 thru 9 and 11 thru 13 as listed in § 1.A.(2) of P ILATUS PC

- 7 Service Bulletin No. 51

- 001 , do a one time i nspection for cracks. If cracks are found, contact P i latus.

NOTE: Repetitive mandatory inspection s will be added to Chapter 5 of the Aircraft Maintenance Manual (AMM). The i nspections will give instructions on how to examine the parts for cracks. The inspections will only be applicable to parts made

from AA2024

- T351.

b) For Item 6 as listed in § 1.A.(2) of PILATUS PC

- 7 Service Bu lletin No. 51

- 001, replace the part with a part made of alumi nium alloy AA2124

- T851.

Ref. Public a tion(s): PILATUS PC

- 7 Service Bulletin No. 51

- 001, initial issue.

The use of later approved revisions of this document is accep table for compliance with the r e quirements of this AD.

For further inform a tion

co n tact: The applicable manufacturer’s documentation may be obtained directly

from:

PILATUS AIRCRAFT LTD. Customer Technical Support (MCC)

P.O. Box 992

CH

- 6371 Stans, Switz erland

Tel.: +41 (0)41 619 67 74 Fax: +41 (0)41 619 67 73

E

- mail: Techsupport@pilatus

- aircraft.com

For further information contact:

FEDERAL OFFICE OF CIVIL AVIATION (FOCA) Design and Production (ST EH)

CH

- 3003 Bern, Switzerland

Fax: +41 (0) 31 322 59 18

E

- mail: airdir@bazl.admin.ch