..

Federal Aviation
Administration

MMEL Policy Letter (PL) 58, Revision 4 GC

Date:

March 24, 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

MMEL GLOBAL CHANGE (GC)

This GC is an approved addendum to all existing MMEL documents.  Operators may seek use of the specific relief contained in this PL by revising their Minimum Equipment List (MEL).  In doing so, each applicable sample proviso stating the relief in this PL, must be copied verbatim in the operatorís MEL.  Approval of a revised MEL is gained utilizing established procedures, through the Operatorís assigned Principal Operations Inspector (POI). This GC Expires 3/12/2016.

SUBJECT:

Flight Deck Headsets and Hand Microphones

MMEL CODE:

23 (COMMUNICATIONS)

REFERENCE:

PL-58, Revision 3, dated July 12, 2001

PL-58, Revision 2, dated August 15, 1997

PL-58, Revision 1, dated December 3, 1993

PL-58, Original, dated October 11, 1991

PURPOSE:

To provide standardized Master Minimum Equipment List (MMEL) requirements for flight deck headsets (microphones and earphones) and hand microphones.

DISCUSSION:

Revision 4 renames PL-58 and rewrites the boom microphone relief, including relief for earphones and noise canceling/reduction functions.  This revision also incorporates hand microphones to the document.

Revision 3 corrected regulation reference from 14 Code of Federal Regulations (14 CFR) section 121.359(e) to 14 CFR section 121.359(g) and adds proviso for cockpit voice recorder (CVR) not equipped to record boom microphone.

Revision 2 reformatted PL-58 with no change to policy.

Revision 1 allowed relief for boom microphone installation not required by 14 CFR.

The original PL-58, dated October 11, 1991, provided the rationale to standardize relief for inoperative boom microphones by permitting a boom microphone to be inoperative for three (3) flight days provided the flight data recorder (FDR) was operative.

 

This policy was appropriate for aircraft required to have boom microphones by 14 CFR sections 121.359(g), 135.151(d), and 125.227(e) In addition, MMEL boom microphone relief is granted to those aircraft that are not required to have a FDR by regulation.

POLICY:

Headsets require standardized MMEL relief for both those installations that are required by 14 CFR and those not required by 14 CFR.  For installations that are not required by 14 CFR, the repair interval will be designated Category "D".  In all cases below, the Observerís seat equipment should be addressed in the associated MMEL item for Observer seat relief.

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

HOLDER OF AN AIR CARRIER OR COMMERCIAL OPERATOR CERTIFICATE

23 COMMUNICATIONS

Repair Interval

Number Installed

Number Required for Dispatch

Remarks or Exceptions

XX-X

Flight Deck Headsets Earphones/ Headphones and Boom Microphones

 

 

 

 

1)

Headset

Boom Microphones

A

-

0

May be inoperative provided:

a)            Associated hand microphone is installed and operates normally, and

b)            Repairs are made within three flight days.

 

 

D

-

-

Any in excess of those required by regulation may be inoperative.

2)

Headset

Earphones/ Headphones

C

-

1

May be inoperative provided associated flight deck speaker operates normally.

 

 

D

-

-

Any in excess of those required by regulation may be inoperative.

3)

Active Noise Canceling/Reduction Function

D

-

0

May be inoperative provided normal audio function of headset is operative.

XX-X

Flight Deck Hand Microphones

C

-

0

May be inoperative provided associated boom microphone operates normally.

 

 

D

-

0

Any in excess of those required by regulation may be inoperative.


 



OPERATOR OTHER THAN A HOLDER OF AN AIR CARRIER OR COMMERCIAL OPERATOR CERTIFICATE

23 COMMUNICATIONS

Repair Interval

Number Installed

Number Required for Dispatch

Remarks or Exceptions

XX-X

Flight Deck Headsets/ Headphones

D

-

-

Any in excess of those required by regulation may be inoperative.

1)

Headset Boom Microphones

A

-

0

May be inoperative provided:

a)          Associated hand microphone is installed and operates normally, and

b)          Repairs are made in accordance with applicable regulations.

 

 

D

-

-

Any in excess of those required by regulation may be inoperative.

2)

Headset Earphones/ Headphones

C

-

1

May be inoperative provided associated flight deck speaker operates normally.

3)

Active Noise Canceling/Reduction Function

D

-

0

May be inoperative provided normal audio function of headset is operative.

XX-X

Flight Deck Hand Microphones

D

-

-

Any in excess of those required by regulation may be inoperative.

 

 

C

-

0

May be inoperative provided associated boom microphone operates normally.

 

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

 

 

 

 

   /s/ Greg Kirkland for

 

 

John S. Duncan

Manager, Air Transportation Division