1、METRIC SUPERSEDING MIL-HDBK-274(AS) 1 November 1983 DEPARTMENT OF DEFENSE HANDBOOK ELECTRICAL GROUNDING FOR AIRCRAFT SAFETY This handbook is for guidance only. Do not cite this document as a requirement. AMSC N/A AREA EMCS MIL-HDBK-274A(AS) 14 November 2011 Provided by IHSNot for ResaleNo reproducti
2、on or networking permitted without license from IHS-,-,-MIL-HDBK-274A ii FOREWORD 1. This handbook is approved for use by the Department of the Navy and is available for use by all Departments and Agencies of the Department of Defense. 2. This handbook is for guidance only. This handbook cannot be c
3、ited as a requirement. If it is, the contractor does not have to comply. 3. This handbook has been prepared to provide U.S. Navy and Marine Corps personnel with the background and technical details of the different types of aircraft grounds and how they are applied. Information related to constructi
4、on of facility radio frequency (RF) grounds, lightning grounds, power safety grounds, and sensitive equipment grounds are addressed in the Naval Facilities Engineering Command (NAVFAC) Unified Facilities Criteria (UFC), “Static Electricity and Lightning Protection Systems.” 4. Comments, suggestions,
5、 or questions on this document should be addressed to : Naval Air Systems Command (Commander, Naval Air Warfare Center Aircraft Division, Code 4L8000B120-3, Highway 547, Lakehurst, NJ 08733-5100) or emailed to Michael.Sikoranavy.mil. Since contact information can change, you may want to verify the c
6、urrency of this address information using the ASSIST Online database at: https:/assist.daps.dla.mil/online/start/. Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-HDBK-274A iii CONTENTS PARAGRAPH PAGE FOREWORD ii1. SCOPE 11.1 Purpose1.2 Backgroun
7、d1.3 Structure2. APPLICABLE DOCUMENTS 12.1 General2.2 Government documents2.3 Non-Government publications 33. DEFINITIONS, ACRONYMS, AND ABBREVIATIONS 43.1 Definitions 43.2 Acronyms and abbreviations 54. GENERAL GUIDANCE 74.1 Theoretical basis for aircraft grounding 74.2 Electrostatic theory4.3 Scen
8、arios4.4 Energy sources4.4.1 Static energy sources 84.4.2 Power 144.4.3 Summary 254.5 Airframe/personnel electrical parameters 254.5.1 Electrostatic charge storage 254.5.2 Electrical properties of aircraft 264.5.3 Aircraft resistance 264.5.4 Aircraft tire resistance4.5.5 Runway material4.5.6 Aircraf
9、t capacitance 264.5.7 Human body electric parameters 264.5.8 Aircraft or capacitor discharge 274.5.9 Discoordination threshold levels4.6 Damage threshold levels4.6.1 Ordnance 274.6.2 Sources of injury from shock 27Provided by IHSNot for ResaleNo reproduction or networking permitted without license f
10、rom IHS-,-,-MIL-HDBK-274A iv CONTENTS PARAGRAPH PAGE 4.6.3 Range for reflex actions 284.6.4 Equipment damage level4.6.5 Summary of damage threshold levels 284.7 Analysis 284.7.1 Source magnitude and hazard threshold level 294.7.2 Time duration consideration 304.7.3 Hazards 304.7.4 Effects of groundi
11、ng 315. DETAILED GUIDANCE5.1 Testing and identification of ground points (ashore) 315.2 Theoretical background 315.2.1 Earths shell 335.2.2 Measuring ground points 335.2.3 Resistance of the ground rod5.3 Measurement equipment5.3.1 Null balance Earth tester 335.4 Ground point measurement procedures 3
12、55.4.1 Three-terminal fall of potential method5.4.2 Two-terminal method (direct method) 355.5 Schedule for resistance testing of ground points 365.6 Identification of ground points 365.7 Use of mooring eyes as static ground points 365.7.1 Mooring eye installation details 365.7.2 Additional tie-down/
13、grounding points 435.8 Resistance measurements for alternate grounding points 435.8.1 Test method for resistance measurements of alternate grounding points 435.9 Operational grounding overview 455.9.1 Operational procedures during ordnance handling 455.9.2 Temporary grounding 465.10 Grounding hardwa
14、re/receptacle considerations 475.10.1 Use of alligator clips or braided panel strap5.10.2 Grounding cable 475.11 Aircraft grounding methods 475.11.1 Grounding for shore-based and shipboard operations 475.11.2 Ordnance loading/downloading 485.11.3 Aircraft ground connectionsProvided by IHSNot for Res
15、aleNo reproduction or networking permitted without license from IHS-,-,-MIL-HDBK-274A v CONTENTS PARAGRAPH PAGE 5.12 Shore-based grounding guidelines 485.13 Shipboard grounding recommendations 515.13.1 Aircraft tie-down chains 525.14 Grounding cable details5.14.1 Ground cable construction 535.14.2 R
16、ecommended cable parts 546. NOTES 546.1 Intended use 546.2 Actual grounding problem 546.2.1 Details of grounding issue 556.3 Responsible technical activity6.4 Changes from previous issue 556.5 Subject term (key word) listingFIGURE PAGE 1. Cloud-inducing charge on aircraft 102. Possible return path f
17、or accumulated charge during remote discharge of clouds 113. Charge accumulation on clothing 134. Lightning current pulse, time domain 235. Lightning current pulse, frequency domain 236. Simple electrical circuit utilizing Ohms Law 327. Illustration of Earths resistance 328. Illustration of Earths s
18、hells 349. Three-terminal test technique10. Three-terminal fall of potential method test setup 3711. Two-terminal method test setup 3812. Measured ground point identification 3913. Mooring eye details 4014. Combination tie-down/grounding receptacle 4115. Static ground receptacle 4216. Resistance mea
19、surement for alternate grounding points 4417. MIL-DTL-83413/7-1 clamp 45Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-HDBK-274A vi FIGURE PAGE 18. M83413/4-1 plug and M83413/4-1 knurled plug 4719. Grounding cable with clamps 5320. Grounding cab
20、le with clamp and plug 5321. Grounding cable reel with clamp and plug 54TABLE PAGE I. Lightning characteristics 21II. Summary of electrical energy sources 25III. Electrical parameters 26IV. Summary of hazard threshold levels 28V. Potential hazard relationship to energy sources and scenarios 31VI. Gr
21、ounding matrix for shore-based operations 49VII. Grounding matrix for shipboard operations 51Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-HDBK-274A 1 1. SCOPE 1.1 Purpose. This handbook has been prepared to provide U.S. Navy and Marine Corps a
22、ircraft maintenance and operations personnel with the background and technical details of the different types of aircraft grounds and how they are applied. In addition, this handbook provides background information for aircraft grounding, static electricity theory and how it affects aircraft, and te
23、chniques used for measurement of grounding points. This handbook is intended for use by all U.S. Navy and Marine Corps aircraft maintenance and operations personnel for the purposes of ensuring that aircraft are properly and safely grounded. This handbook is for guidance only and cannot be cited as
24、a requirement. 1.2 Background. The philosophical position and technical information presented in this handbook are based upon results of a previous naval study documented in NAVAIR Report AIR-5181-1000, “Airframe Electrical Grounding Requirements Program Final Report.” That study demonstrated that h
25、azards exist during aircraft maintenance and established that there are valid technical reasons to ground aircraft. It also recognized that a rigorous grounding philosophy is necessary to maximize personnel and aircraft safety. Aircraft grounding methods presented in this handbook describe procedure
26、s for static grounding of aircraft during all maintenance actions including fueling/de-fueling and ordnance loading or unloading evolutions. The procedures in this handbook apply to both fixed wing and rotary wing aircraft. The grounding methods presented in this handbook make a clear distinction be
27、tween static grounding and power grounding. Information related to construction of facility radio frequency (RF) grounds, lightning grounds, power safety grounds, and sensitive equipment grounds are addressed in the Naval Facilities Engineering Command (NAVFAC) UFC 3-570-01,Unified Facilities Criter
28、ia (UFC) document titled, “Static Electricity and Lightning Protection Systems.” 1.3 Structure. This handbook provides guidance on grounding for safety of personnel, aircraft and aircraft equipment. It may also be used for guidance to verify facility ground points. 2. APPLICABLE DOCUMENTS 2.1 Genera
29、l. The documents listed below are not necessarily all of the documents referenced herein, but are those needed to understand the information provided by this handbook. 2.2 Government documents. 2.2.1 Specifications, standards, and handbooks. The following specifications, standards, and handbooks for
30、m a part of this document to the extent specified herein. Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-HDBK-274A 2 DEPARTMENT OF DEFENSE SPECIFICATIONS MIL-DTL-83413 - Connectors and Assemblies, Electrical, Aircraft Grounding, General Specific
31、ation for MIL-DTL-83413/4 - Connectors and Assemblies, Electrical, Aircraft Grounding: Plugs, for Types I and II Grounding Assemblies MIL-DTL-83413/7 - Connectors and Assemblies, Electrical, Aircraft Grounding: Grounding Clamp for Types I and III Grounding Assemblies, Clip, Electrical DEPARTMENT OF
32、DEFENSE STANDARDS MIL-STD-464 - Electromagnetic Environmental Effects Requirements for Systems DEPARTMENT OF DEFENSE HANDBOOKS MIL-HDBK-235-1 - Military Operational Electromagnetic Environment Profiles Part 1C General Guidance (Copies of these documents are available online at https:/assist.daps.dla
33、.mil/quicksearch/ or from the Standardization Document Order Desk, 700 Robbins Avenue, Building 4D, Philadelphia, PA 19111-5094.) 2.2.2 Other Government documents, drawings and publications. The following other Government documents, drawings, and publications form a part of this document to the exte
34、nt specified herein. NAVAL AIR SYSTEMS COMMAND NAVAIR 00-80T-96 - U.S. Navy Support Equipment, Basic Handling and Safety Manual NAVAIR 00-80T-109 - Aircraft Refueling NATOPS Manual NAVAIR 00-80T-122 - Helicopter Operational Procedures for Air-Capable Ships NATOPS Manual NAVAIR AIR-5181-1000 - Airfra
35、me Electrical Grounding Requirements Program Final Report NAVFAC TS-02614 - Joints, Reinforcement, and Mooring Eyes Concrete Pavement Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-HDBK-274A 3 (Copies of these documents are available online at h
36、ttps:/mynatec.navair.navy.mil/ or from the NAVAIR Scientific and Technical Library, Building 407, 22269 Cedar Point Road, Patuxent River, MD 20670.) NAVAL SEA SYSTEMS COMMAND NAVSEA OP 4 - Ammunition and Explosives Safety Afloat NAVSEA OP 5 - Ammunition and Explosives Safety Ashore (Copies of these
37、documents are available from the Naval Ordnance Safety and Security Activity online at: https:/nossa.nmci.navy.mil/nrws3/Programs/ExplosivesSafetyOperations/Library/CurrentPublications.aspx.) 2.3 Non-Government publications. The following documents form a part of this document to the extent specifie
38、d herein. AMERICAN NATIONAL STANDARDS INSTITUTE (ANSI) ANSI C63.14-1992 - American National Standard Dictionary for Technologies of Electromagnetic Compatibility (EMC), Electromagnetic Pulse (EMP), and Electrostatic Discharge (ESD) (Copies of these documents are available from http:/webstore.ansi.or
39、g or American National Standards Institute, 1899 L Street NW, 11thFloor, Washington, DC 20036.) SAE INTERNATIONAL SAE-AS25486 - Connector, Plug, Attachable, External Electric Power, Aircraft, 115/200 Volt, 400 Hertz SAE-AS25487 - Connector, Plug, Attachable External Electric Power, Aircraft, 28 Volt
40、 DC, Jet Starting SAE-AS25488 - Connector, Plug, Attachable External Electric Power, Aircraft, 28 Volt DC, Operating Power (Copies of these documents are available from http:/standards.sae.org or SAE International, 400 Commonwealth Drive, Warrendale, PA 15096-0001.) Provided by IHSNot for ResaleNo r
41、eproduction or networking permitted without license from IHS-,-,-MIL-HDBK-274A 4 3. DEFINITIONS, ACRONYMS, AND ABBREVIATIONS 3.1 Definitions. For the purpose of this handbook, the following definitions apply. In addition to the terms below, many terms used in this handbook are defined in ANSI C63.14
42、, JCS Pub. 1-02, DoDD 3222.3, DoDI 4650.01, or the DoD 5000 series of documents. Bond. Any fixed union between two surfaces that result in electrical conductivity between the surfaces. The union occurs either from physical contact between conductive surfaces of the surfaces or from the addition of a
43、 firm electrical connection between them. For refueling/defueling purposes the bond is the conductive contact between the refueling apparatus and the aircraft. Breech. The rear part of the bore of a gun, especially the opening and associated mechanism that permits insertion of a projectile. Coulomb
44、(C). The charge transported by a steady 1 ampere current in 1 second. Fibrillation. Fibrillation is the rapid, irregular, and unsynchronized contraction of muscle fibers. An important occurrence is with the heart. Friction. A force on objects or substances in contact with each other that resists mot
45、ion of the objects or substances relative to each other. Induced Charge. Induced charge is one that accumulates on an object when immersed in an electric field. Lightning Grounds. Lightning grounds are grounds that have resistances lower than 1 ohm and frequently on the order of 2.5 milliohms or les
46、s. In, addition lightning grounds must be more robust than Static/ESD grounds so that they may conduct extremely high lightning-induced currents on the order of several thousands of amperes. Ohms Law. Ohms Law states that the current through a conductor between two points is directly proportional to
47、 the potential difference (voltage) across the two points, and inversely proportional to the resistance between them. Ordnance Ground. Ordnance grounds are static grounds typically found in magazines and ordnance handling areas. Power Grounds. Power grounds are defined as those having resistances of
48、 less than 25 ohms referenced to the power system neutral. For further information on power grounds refer to individual system technical manuals and design documents, such as NAVFAC UFC 3-570-01. Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-HDBK-274A 5 Radio Frequency (RF) Grounds. RF grounds are grounds that protect systems from voltages and currents induced from internal system generated electromagnetic fields and from external electromagnetic fields. Static Electricity. An accumulation of electric ch
