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HQ 958076

OCTOBER 19, 1995

CLA-2 R:C:M 958076 JAS


TARIFF NO.: 7019.20.40

Mr. D. E. Adams
Boeing Commercial Airplane Group
P.O. Box 7730
Wichita, KS 67277-7730

RE: Insulation Blankets for Aircraft Engine Thrust Reversers and Struts; Contoured Articles of Thin Gauge Stainless Steel and Silica Powder Wrapped in Fiberglass Cloth; Thermal Blankets, Parts of Turbojets, Subheading 8411.91.90; Accessories; Other Parts of Airplanes, Subheading 8803.30.00, Civil Aircraft Agreement (CA); Composite Good Made Up of Different Components, GRI 3

Dear Mr. Adams:

Your letter of June 9, 1995, concerns the tariff status of thermal insulating blankets for aircraft engine thrust reversers and struts. You submitted additional information in facsimile transmittals, dated September 28 and October 2, 1995.


The articles in question are thermal insulation blankets composed of thin gauge stainless steel, fiberglass cloth, and Min-K, a micro-porous silica material in fine white powdered form. The Min-K is placed between two pieces of flexible fiberglass cloth which is stitched horizontally and vertically to form a blanket. The stainless steel is formed into a contoured, crest-like shape, then folded under and spot welded to encase the blanket on both sides in the manner of a frame.

These blankets function primarily to provide thermal protection for thrust reversers and support struts against the heat generated by Rolls Race engines for the Boeing 757 class aircraft. Complete insulation blankets are cut-to-size and contoured and are mechanically fastened to the inner wall of a thrust reverser and at the point where a strut pylon joins the nacelle. Thrust reversers are attached to cowlings or nacelles, which are the outer metal covers that house the plane's engines - 2 -
but are not integral to the engines. Struts are structural members that connect the engine to the wings.

To decrease airspeed in preparation for landing, the pilot deploys the thrust reversers located in the nacelle/cowling housing. This reposition movable doors incorporated in the thrust reverser that diverts air entering the front of the nacelle over contoured vanes or louvers called cascades to produce reverse thrust.

You state that the thermal insulation blankets are not parts of the aircraft engine. Rather, they are integral to nacelles and struts. Because nacelles and struts are aircraft parts provided for in subheading 8803.30.00, Harmonized Tariff Schedule of the United States (HTSUS), a duty-free provision for other parts of airplanes or helicopters, you contend the insulation blankets should be similarly classified.

The provisions under consideration are as follows:

6815 Articles of stone or of other mineral substances (including articles of peat), not elsewhere specified or included:

Other articles:

6815.99 Other:

6815.99.40 Other...3.6 percent

7019 Glass fibers (including glass wool) and articles thereof (for example, yarn, woven fabrics):

7019.20 Woven fabrics, including narrow fabrics:

Narrow fabrics:


7019.20.40 Other...8.2 percent

7326 Other articles of iron or steel:

7326.90 Other:

7326.90.85 Other...5.1 percent

8803 Parts of goods of heading 8801 or 8802:

8803.30.00 Other parts of airplanes or helicopters...Free


Whether the thermal insulation blankets are parts of airplanes or accessories.


Merchandise is classifiable under the Harmonized Tariff Schedule of the United States (HTSUS) in accordance with the General Rules of Interpretation (GRIs). GRID 1 states in part that for legal purposes, classification shall be determined according to the terms of the headings and any relative section or chapter notes, and provided the headings or notes do not require otherwise, according to GRIs 2 through 6. GRID 3(b) states in part that composite goods consisting of different materials or made up of different components which cannot be classified under 3(a) shall be classified as if consisting only of the material or component which gives them their essential character, insofar as this criteria is applicable. GRI 3(c) provides that goods which cannot be classified by reference to 3(a) or 3(b) shall be classified under the heading which occurs last in numerical order among those which equally merit consideration.

The Harmonized Commodity Description And Coding System Explanatory Notes (ENs) constitute the official interpretation of the Harmonized System. While not legally binding on the contracting parties, and therefore not dispositive, the ENs provide a commentary on the scope of each heading of the Harmonized System and are thus useful in ascertaining the classification of merchandise under the System. Customs believes the notes should always be consulted. See T.D. 89-80, 54 Fed. Reg. 35127, 35128 (Aug. 23, 1989).

Heading 8803 provides for parts of goods of heading 8801 or 8802. It does not provide for accessories. The term "accessory" is not defined either in the HTSUS or in the Explanatory Notes. However, Webster's Third New International Dictionary (1961) defines an accessory as "an object or device that is not essential in itself but adds to the * * * effectiveness of something else." Webster's New International Dictionary, Second - 4 -

Edition (1954) provides a nearly identical definition. The fact that these thermal insulation blankets may be certified by the Federal Aviation Administration for use in civil aircraft is not legally relevant if they are not parts in a tariff sense. The plane's engines are complete and fully functional as a means of propulsion or thrust, and the struts are structural members, both without regard to the thermal insulation blankets. There is no compelling argument that these articles are parts for tariff purposes because neither the engine nor strut depends on a thermal insulation blanket for its completeness or function. The insulation blankets are accessories for tariff purposes.

The thermal insulation blankets consist of different materials and/or components for which no HTSUS heading provides a specific description. The contoured stainless steel frame is provided for in heading 7326, as an article of iron or steel; the powdered silica is provided for in heading 6815, as an article of stone; and the fiberglass cloth is provided for in heading 7019 as an article of glass fibers. Under GRI 3(b) the thermal insulation blankets are to be classified as if consisting only of the material or component that gives them their essential character.

The contoured steel frame provides rigidity, form and shape to the insulation blanket and is the means for attaching the insulation blanket to the thrust reverser. Its insulation capability, however, is minimal. Technical information you made available to us indicates that while the woven fiberglass cloth is a thermal barrier, its main function is to contain or give form and shape to the silica. It is the silica, we are informed, that is the primary insulating material because of its low thermal conductivity. The silica does not absorb the heat, rather it dissipates the heat around the thrust reverser and out nearby ducts. However, another source of technical information indicates that the silica has minimal thermal insulating capability, and acts primarily as a heat sink to radiate heat throughout the entire mass of the silica. This prevents too much heat from building up in any one part of the silica. This source indicates it is the fiberglass cloth that is the primary insulant. Certainly, the fiberglass is the more costly component and provides greater mass or bulk to the blanket. In resolving issues of essential character the ENs, at p. 4, authorize us to consider the nature of a material or component, its bulk, quantity, weight or value among other relevant factors.

Nevertheless, we conclude that the evidence available at this time is inconclusive as it relates to the issue of essential character. For this reason, under the authority of GRI 3(c), the thermal insulation blankets are to be classified in heading 7019, as this is the heading which occurs last in numerical order from - 5 -
among those that equally merit consideration. We do not consider heading 7326 to merit equal consideration.


Under the authority of GRI 3(c), the thermal insulation blankets are provided for in heading 7019 as glass fibers and articles thereof. They are classifiable in subheading 7019.20.40, HTSUS.


John Durant, Director
Tariff Classification
Appeals Division

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