NPFC - MIL-HDBK-274
ELECTRICAL GROUNDING FOR AIRCRAFT SAFETY
| Organization: | NPFC |
| Publication Date: | 29 June 1990 |
| Status: | inactive |
| Page Count: | 295 |
scope:
Purpose. The purpose of this handbook is to provide aircraft maintenance personnel with the information required for electrical safety grounding of each type of operational aircraft in the U .S. Navy inventory." In addition, this handbook provides background information pertaining to the operational concerns for aircraft grounding,.static electricity theory and how it affects aircraft, and techniques used for measurement of grounding points. This handbook is divided into five sections as follows:
SECTION 1 - SCOPE
SECTION 2 - AIRCRAFT GROUNDING AND BONDING METHODS
SECTION. 3 - OPERATIONAL GROUNDING CONCERNS
SECTION 4 - THEORETICAL BASIS FOR AIRCRAFT GROUNDING
SECTION 5 - TESTING AND IDENTIFICATION OF GROUND POINTS
This handbook is intended for use by U .S. l Naval aircraft operational and maintenance personnel including maintenance officers and public works officials for the purpose of ensuring that each aircraft is properly grounded and that the grounding system is adequate for this purpose.. Sec1t ainodn s 2 are intended primarily for use by line maintenance personnel. Section3o and 4 contain material intended for those desiring to obtain additional theoretical and background information. Section 5 is essential for public works department personnel. Each section is designed to stand alone.
The information contained in Section 2 is s intended t o be used by line maintenance personnel. This section provides step-by-step instructions for grounding each of the aircraft in the Navy inventory during each of the following evolutions: parked, fueling/defiling, maintenance, and stores loading/ unloading. Each evolution is shown in a separate illustration depicting the particular aircraft with proper grounding/bonding cables connected. The illustrations show primary grounding points and also provide alternate grounding points should the primary grounding points be inaccessible. Also provided on the illustrations are pertinent cautions and warnings to be observed during the grounding procedure. Accompanying each illustration is a step-by-step procedure for grounding/bonding the particular aircraft.
Section 3 provides background and general information necessary to understand the rationale behind the requirements for grounding and bonding. This section also discusses- the grounding problems and hazards encountered in the everyday ground handling of aircraft during flight operations. Energy sources and grounding effects are identified. The aircraft scenarios or servicing situations (evolutions) are introduced and e aircraft safety problems associated with each are described. In addition, a brief discussion of static electricity and how it affects aircraft operation is provided.
Navy aircraft use power equipment not equipped with ground fault interrupters ' (GFI) .
Section 4 details basic electrostatic theory and its application to aircraft grounding. Sources of static electricity associated with aircraft operation are also described, These include triboelectric effects, fuel flow, induced charge, and friction. Hazards from ground power faults, rf energy, and lightning are presented. Also included in this section are descriptions of aircraft electrical parameters and a discussion of hazardous threshold and the possible dangers they present to personnel and aircraft safety. section also illustrates that proper grounding will reduce these hazards.
Section 5 is intended for use by the public works department personnel and provides a description of the methods and techniques used to measure the resistance of the grounding system. Also included in VS is on a suggested schedule for accomplishing the measurement of ground points, identifying ground points, the use of mooring eyes as static ground points, and a discussion of the test equipment used to measure ground point resistance.
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