...

Federal Aviation
Administration

MMEL Policy Letter 112, Revision 2 

Date:

January 18, 2012

To:

All Region Flight Standards Division Managers
All Aircraft Evaluation Group Managers

From:

Manager, Air Transportation Division, AFS-200

Reply to Attn of:

Manager, Technical Programs Branch, AFS-260

SUBJECT:

Relief for 14 CFR 25.795 Compliant Flight Deck Doors

MMEL CODE:

52

REFERENCE:

PL-112, Revision 1, dated January 29, 2004

PL-112, Original, dated June 28, 2002

AC 25.795-1A

PURPOSE:

This policy letter provides guidance to Flight Operations Evaluation Board (FOEB) Chairmen for standardized Master Minimum Equipment List (MMEL) relief for 14 CFR, Section 25.795 Security considerations, compliant flight deck doors.

DISCUSSION:

Revision 2 removes Global Change and clarifies relief for flight deck doors with a decompression function that is independent of the primary door locking system.

 

Revision 1: Added title (Passenger/Combi Aircraft Only) and example provisos (Primary and Secondary Locking Systems) for new flight deck door(s) and establishes time deferral limits for use within MMELs.

 

Revision Original: As a result of the September 11, 2001 attacks by terrorists whose focus included United States aviation interest as targets, the U.S. Government, the Federal Aviation Administration, and the U.S. aviation industry joined together to increase levels of aviation security including transport airplane flight deck security.  Passage of SFAR 92 and subsequent Amendments 92-1 through 92-4, Amendments

25.106 and 121.288, along with the approval of 25.795-6?OpenDocument')">Advisory Circulars 25.795-1 and 25.795-2, highlighted some of the regulatory activities that supported increased security awareness.  The newly designed 14 CFRs provide for more robust flight deck door designs on transport aircraft that will be utilized in service by U.S. operators.  The U.S. operating rules (14 CFR) provide MMEL/MEL relief for inoperative equipment subject to specified conditions.  U.S. operating rules (14 CFR section 121.587) have required locked flight deck doors during 14 CFR part 121 operations for approximately 40 years (August 6, 1964).  Policy letters provide guidance specific to the management and oversight of the MMEL/MEL approval process.


 

POLICY:  

FOEB chairmen may not allow relief for flight deck doors, as a system, however they may allow relief for certain specific items associated with the design of flight deck doors, as has been the Flight Operations       Policy Board's (FOPB) long standing practice. The normal FOEB practice of considering the type of failure and the next probable failure in the granting of MMEL relief must be followed, and an acceptable level of safety must be maintained. In all cases the primary consideration will be the maintenance of flight deck security and the prevention of unauthorized access, as required by 14 CFR.

           

Further, any flight deck door locking device in use in 14 CFR part 121 operations must meet the requirements of 14 CFR section 25.795, as amended. The part(s) of the system that alerts the flight crew that the auto opening cycle has been activated, and that the door locking system is entering the unlocked mode, must be operative, unless the auto-opening system has been deactivated. The part(s) of the system that allows the flight crew to take immediate action to cause the door to remain locked or default to a locked mode, until positive (visual) identification of the person seeking entry can be validated,       must remain operative, unless a tertiary locking device is used that does not allow flight deck access.

 

The FOPB is aware that some designs may incorporate tertiary locking features or locking features that were originally designed for use in other than in-flight operations. These latter locking features, or       system attributes, may be accompanied by placards labeled "For Ground Use Only", etc. While Aircraft Certification may not have envisioned the use of those kinds of devices in-flight, considering that the use       of those particular systems would not meet the requirements for aircraft certification; the FOPB believes that the use of certain of these devices will enable the operator to maintain a level of safety,       considering the unauthorized entry case, by using these devices at dispatch, where certain door locking failures occur in service. Additionally, the use of certain of these features will provide safety benefits after an enroute failure of the primary locking system(s).

 

In these cases, the FOEBs are encouraged to utilize these locking system resources to good advantage. Provisos should address alternative Placarding provisions, when appropriate, that specify when the use of appropriate alternative locking subsystems may provide an additional safety benefit.

 

Inoperative components of the door locking system may be considered for MMEL/MEL relief, if it is determined that the door may be locked and the locked indication is clearly visible or discernable to the       flight crew.

 

The following standard MMEL proviso and repair category is adopted to provide standardization among all MMELs.


Passenger and Combi airplanes with decompression function Dependent of primary locking system:

52 DOORS

 

 

 

 

-XX Enhanced Flight Deck Security Door Primary Locking System

(FAR 25.795 Compliant)

***

A

1

0

(M)(O) May be inoperative provided:

a) Primary locking system is deactivated,

b) Secondary locking system operates normally and is used to lock the door,

c) Alternate procedures are established and used for locking and unlocking the door using the secondary locking system, and

d) Repairs are made within two flight days

-XX Enhanced Flight Deck Security Door Secondary Locking System

(FAR 25.795 Compliant)

***

C

1

0

May be inoperative provided primary locking system operates normally.

 

 

Passenger and Combi airplanes with decompression function Independent of primary locking system:

52 DOORS

 

 

 

 

-XX Enhanced Flight Deck Security Door Primary Locking System

(FAR 25.795 Compliant)

***

C

1

0

(M)(O) May be inoperative provided:

a) Primary locking system is deactivated,

b) Secondary locking system operates normally and is used to lock the door and

c) Alternate procedures are established and used for locking and unlocking the door using the secondary locking system.

 

-XX Enhanced Flight Deck Security Door Secondary Locking System

(FAR 25.795 Compliant)

***

C

1

0

May be inoperative provided primary locking system operates normally.

-XX  Flight Deck Door Decompression Panel Decompression Function

(FAR 25.795 Compliant)

***

A

-

0

May be inoperative provided:

a)            Panels are in the latched position, and

b)            Repairs are made within two flight days.

 

Each Flight Operations Evaluation Board (FOEB) Chairman should apply this Policy to affected MMELs through the normal FOEB process.

 

 

 

 

 

        /s/ G Kirkland for

John Duncan

Manager,

Air Transportation Division, AFS-200