Federal Aviation
Administration

MMEL Policy Letter 94 Revision 1

Date:

October 8, 2004

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:

Liquid or Paste Propeller Deicer

MMEL CODE:

61 (PROPELLERS) and 30 (ICE & RAIN PROTECTORS)

REFERENCE:

PL-13, Revision 1, dated February 23, 1984 (Item 11) signed by William T Brennan

PURPOSE:

The following guidance is to clarify the agency policy on use of liquid or paste propeller deicer.

DISCUSSION:

This policy was previously contained as the No. 11 item in former Policy Letter 13, dated February 23, 1984, which covered multiple issues.

Revision 1 provides FOEB chairmen the authority to grant MMEL relief for airplanes that have the same engine/propeller combination as an airplane that has AFM approval to use an approved liquid or paste in lieu of an operable propeller deicer system.

Previously certain MMELs permit operations under IFR and/or into known forecast icing conditions with an inoperative propeller deicing system provided an approved liquid or paste is properly applied.  The B.F.  Goodrich Company manufactures a product called "ICEX," which is designed and sold to be used with an operable deicer system.  Its sole purpose is to improve deicer performance and efficiency. Apparently, several operators are using this product and applying it to propeller deicer boots and dispatching aircraft into IFR and icing conditions with inoperative propeller heaters.  The B.F. Goodrich Company has no FAA approvals for the use of  "ICEX."  Also, the Southwest Region's Airplane Certification Branch, ASW-150, advised that no specific FAA evaluations were conducted where a liquid or paste was substituted for an operable system during icing certification tests.

However, in review of some earlier propeller aircraft MMELs, this type of liquid or paste is referenced in certain MMELs based on authority contained in the specific AFMs.

POLICY:

FOEB chairmen must ensure that MMELs for propeller aircraft only permit use of an approved liquid or paste in lieu of an operable propeller deicer system if:

1.   The Airplane Flight Manual (AFM) specifically approves its use; or

2.   The airplane has the same engine/propeller combination as an airplane that has AFM approval to use an approved liquid or paste in lieu of an operable propeller deicer system (i.e. L-188 and L-382/C-130 airplanes with Allison 501 engines and Hamilton Standard propellers).

 

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

 

Matthew Schack, Manager,

Air Transportation Division, AFS-200

 

PL-94 reformatted on 01/20/2010 with no change to content.