CLA-2:CO:R:C:G 087979 JAS

District Director of Customs
110 S. Fourth St., rm. 137
Minneapolis, Minnesota 55401

RE: Slat-Flap Control Computer (SFCC); Aircraft Wing Slat/ Flap Positioning Device; Programmed Base for Electric Control; Navigational Instrument; Automatic Regulating or Controlling Instrument; Civil Aircraft Agreement; 8537.10.00, 8803.30.00, 9014.20.60, 9031.80.00, 9032.89.60, HTSUS

Dear Sir:

This is our decision on Application for Further Review of Protest No. 3501-0-000096, dated April 25, 1990, filed by counsel on behalf of Northwest Airlines, Inc., Minneapolis, Minnesota. Additional arguments were made by NWA's counsel in a meeting at Headquarters on February 27, 1991, and confirmed in a brief dated March 22, 1991.


The Slat/Flap Control Computer (SFCC) from Germany is described as a device used to set and monitor the wing slats and flaps of the NWA A320 twin turbo-fan passenger aircraft. It regulates and monitors the flow of fluid in a hydraulic actuator which positions the slats and flaps in accordance with the pilot's command.

In operation, when the pilot activates the flap control lever the Command Sensor Unit sends an electronic signal containing the positioning information to the SFCC. The SFCC then relays the signal to the hydraulic actuator (Power Control Unit). The PCU turns a drive shaft that moves a screw jack which in turn mechanically positions the flaps and slats. Counsel states that once positioned, the SFCC utilizes data generated by feedback position pick off sensors located on the wings that report slat/flap position to the SFCC. In the event the slats and flaps move into an asymmetric position the SFCC will automatically return them to the original position designated by the pilot. - 2 - It is stated that the SFCC interfaces with other devices on the aircraft which flash a warning to the pilot if the slats and flaps are positioned incorrectly. Counsel also maintains the SFCC has pilot override capability. This allows the SFCC to analyze information from other on-board systems monitoring speed, angle of travel, etc. If it determines from this analysis that an unsafe condition will result from the indicated slat/flap position, the SFCC will override the pilot's command.

You describe the SFCC as a box that controls a hydraulic actuator that positions the plane's slats and flaps. Accordingly, you liquidated the entries in question under the provision for boards, panels, consoles, and other bases for electric control or the distribution of electricity [programmable controllers], in subheading 8537.10.00, HTSUS.

Counsel claims that the SFCC is classifiable under the duty- free provision for other parts of airplanes for use in civil aircraft, in subheading 8803.30.00, Harmonized Tariff Schedule of the United States (HTSUS). Alternatively, he proposes classification in subheading 9032.89.60, HTSUS, automatic regulating or controlling instruments and apparatus, in subheading 9031.80.00, as other measuring or checking instruments, appliances and machines, or in subheading 9014.20.60, HTSUS, other electrical instruments and appliances for aeronautical or space navigation. The rate of duty for these provisions under the Agreement on Trade in Civil Aircraft is free.


Whether the SFCC is a base for electric control of heading 8537, either programmed or programmable; if it is either, whether the claimed alternative classifications, or any of them, are relatively more specific.


Merchandise is classifiable under the Harmonized Tariff Schedule of the United States Annotated (HTSUSA) in accordance with the General Rules of Interpretation (GRIs). GRI 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.

The Harmonized Commodity Description and Coding System Explanatory Notes (ENs) constitute the Customs Cooperation Council's official interpretation of the Harmonized System. While not legally binding on the contracting parties, and - 3 -

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.

Initially, articles of chapter 90 are precluded from classification in heading 8537, assuming that provision applies. Section XVI, Note 1(m), HTSUS. Therefore, if any of headings 9031, 9032 or 9014 apply, the SFCC must be classified therein. We will discuss each of these claims in the order presented by counsel.

Initially, we believe the SFCC is provided for in heading 8537. Goods of heading 8537 vary from small switchboards with only a few switches, fuses, etc. to complex control panels for large installations. These include, for example, numerical control panels, programmed switchboards that control apparatus, programmable controllers, and other bases for electric control or the distribution of electricity. Therefore, heading 8537 includes both programmed and programmable bases for electric control.

Relevant ENs under (3) at p. 1391, indicate that "Programmable controllers" of heading 8537 are digital apparatus using a programmable memory for the storage of instructions for implementing specific functions such as logic, sequencing, timing, counting, and arithmetic, to control, through digital analog/output modules, various types of machines. A programmable controller's ultimate purpose is to control output devices. It does this by reading input signals from pushbuttons, contacts or switches and deciding what the outputs should be, based on the user's program logic. It then takes the logic-level signals from the program logic solver and converts them to output signals which it then sends to output devices such as solenoids, valves, etc. The SFCC functions precisely in this manner with its principal purpose being to control the hydraulic actuator which positions the plane's wing slats and flaps.

The heading 9032 classification is based on two alternative claims. The first claim is that the purpose of the SFCC is to control the movement of a non-electric quantity (the hydraulic fluid) through an electrical control device, the operation of which depends on the transmission of an electrical signal which varies according to the factor to be controlled. We disagree. The principal purpose of the SFCC is to control or adjust the position of the wing slats and flaps. Controlling the fluid distribution in the hydraulic actuator is merely an intermediate process by which this primary purpose is accomplished. - 4 -

Alternatively, counsel claims that the basic function of the SFCC is to control the flow and pressure of air (a gas) over the surface of the A320's wings. Pursuant to Chapter 90, Note 6, HTSUS, instruments and apparatus of heading 9032 include those which control the flow, level, pressure and other variables of liquids or gases. Relevant ENs, at pp. 1533 and 1534, indicate that such apparatus usually consists of three devices forming a single entity: a device for measuring the variable to be controlled, a control device - sometimes optional - which compares the measured value with the desired value and a starting, stopping or operating device actuated by the control device. The ENs state further that automatically controlling instruments and apparatus of heading 9032 are connected to an appliance such as a pump, compressor or valve which carries out the orders. By function and design, the SFCC controls a sequence of mechanical movements in the wings' slats and flaps, which proximately alter the flow and pressure of air over the wings. However, because the SFCC neither incorporates a device for measuring the variable (air) to be controlled nor a control device for comparing the measured value with the desired value, we conclude it is not within the instruments and apparatus encompassed by heading 9032.

The 9031 claim is based on counsel's contention that the SFCC not only positions the slats and flaps but continuously monitors their position and repositions them if they become asymmetrical. In addition, the SFCC is said to interface with other navigational computers on board the aircraft by feeding them slat/flap positions so that airspeed, rate of ascent/ descent, ailerons, etc. can be modified. Our interpretation of the available information is that these other navigational computers may measure, check and, if necessary, adjust the function or variable they are designed to control utilizing data received from the SFCC. There is no evidence that the SFCC independently measures or checks anything.

Regarding the heading 9014 claim, the common meaning of the terms navigate or navigation connotes the science or art of conducting aircraft from one place to another; especially, the method of determining position, course and distance travelled over the surface of the earth by the principles of geometry and astronomy, and by reference to instruments used as aids. The ENs, at p. 1481, (C)(1) through (7), list various meters and indicators which measure or determine aerodynamic variables and provide the pilot with information from which he can determine, maintain or alter the plane's course. The exemplars, however, are noninclusive. The correct positioning and maintaining of the slats and flaps determines the plane's proper rate of ascent and descent, and therefore relates to the plane's course or position. - 5 -

The SFCC's function of warning the pilot if the slats/flaps become asymmetrical certainly qualifies as a navigational aid. We conclude that the SFCC is provided for in heading 9014. As a historical note, devices that primarily control a plane's horizontal movements and have the capacity to correct a deviation if the aircraft is flying at a wrong angle, have been regarded as navigational instruments under the TSUS, provided they are not also electric measuring, checking, analyzing or automatically controlling instruments or apparatus. Ruling 067317, dated June 10, 1982.


The Slat/Flap Control Computer (SFCC) in issue here is described by heading 8537, HTSUS. However, because of Section XVI, Note 1(m), HTSUS, it cannot be classified in chapter 85. Under the authority of GRI 1, the SFCC is provided for in heading 9014. Actual classification is in subheading 9014.20.60, HTSUS, other electrical instruments and appliances for aeronautical or space navigation. The rate of duty on such instruments and appliances under the Agreement on Trade in Civil Aircraft is free. The protest should be allowed. A copy of this decision should be attached to the Customs Form 19 and mailed to the protestant, through counsel, as part of the notice of action on the protest.


John Durant, Director
Commercial Rulings Division