雷击

Background

• Aluminum Structure

• Lightning Damage

• Typical Inspections and Repairs

• Composite Structure

• Lightning Protection

• Lightning Damage

On average, an airplane is struck by lightning

once every 3,000 flight hours

• Airplanes that fly shorter routes are struck more

often than longer haul airplanes

• Exposure to lightning environment for a greater

percentage of flight time

• A single bolt of lightning can contain as much as

1 million volts or 30,000 amps

估计平均每架飞机每年遭受轻微雷击的次数不少于一次。在世界上一些多雷区服役的飞机遭受雷击的频率明显比较高。事实上，当飞机飞过放电现象严重的多云区时，就很容易激发雷击事件。试验表明，影响雷击可能性的一个重要因素是飞机的长度，也就是飞机长度超过翼展宽度时更容易遭雷击。

It is estimated that on average, an airplane is struck slightly more than once per

year. Airplanes that operate in parts of the world where lightning activity is more

prevalent would obviously experience elevated frequency of lightning strikes. In

fact, airplanes may trigger lightning when flying through a heavily charged region

of a cloud. Laboratory tests show that an important factor affecting lightning

strike

attachment potential is airplane length, as length exceeds wing span.

估计平均每架飞机每年遭受轻微雷击的次数不少于一次。在世界上一些多雷区服役的飞机遭受雷击的频率明显比较高。事实上，当飞机飞过放电现象严重的多云区时，就很容易激发雷击事件。试验表明，影响雷击可能性的一个重要因素是飞机的长度，也就是飞机长度超过翼展宽度时更容易遭雷击。

If an airplane has had a lightning strike, a general examination of the airplane must

be made to find the area of the initial strike and the point of electrical

discharge.

Once found, a complete examination must be made to find all the damage resulting

from the strike.

The lightning channel is somewhat stationary in space while it is transferring the

electrical charge. When an airplane is struck, it becomes part of that channel.

However, due to the speed of the airplane and the length of time that the lightning

channel exists, the airplane moves relative to the channel. When a forward

extremity, e.g. a nose, is involved, the airplane moves through the lightning

channel. Thus, the lightning channel appears to sweep back over the airplane,

which is known as the “swept stroke.”

As the sweeping action occurs, the lightning channel can attach and dwell at

various surface locations, resulting in a skipping action which produces a series of

individual attachment points along the sweeping path. Due to this, portions of the

airplane that would not normally be targets for the initial attachment and exit point

of a lightning flash may be involved in the process as the flash is swept backwards

across the airplane. It is possible the static discharger is the exit point for some

lightning strikes.

如果一架飞机遭到雷击，必须作一次全面的检查找出初始雷击区和放电点；一但找到雷击区，必须做一个彻底的检查找出所有因雷击而遭受的损伤。

闪电的路线在空中是相对静止的，它起到传输电流的作用。当一架飞机遭到雷击时，这架飞机便成为闪电路线的一部分。然而由于飞机是运动的，而且闪电有一定的持续时间，因此飞机相对于闪电线路来说是移动的。飞机从最前端的一点，例如雷达罩开始，穿过闪电路线。因而闪电的路线好像是往后扫过这架飞机，我们把它称之为“扫描式雷击”。

当发生扫描式雷击时，闪电的线路可能会在飞机表面的各个位置点略微停留，从而产生“跳跃”现象，最终导致在“扫描”路线上形成一系列雷击点。因此，飞机的有些区域在正常情况下不会成为初始雷击点和放电点，但由于闪电往后扫描，因而这些区域也会遭受雷击。在有些雷击中，静电放射器会成为闪电的放电点。

A lightning strike always has at least one attachment (or damage entrance point)

and one exit point. It is impossible for the airplane to store the lightning energy.

Typically, the initial attachment and exit points are at the extremities of the

airplane, which include the nose, wing tips, elevator and stabilizer tips, protruding

antennas, and engines. Lightning can also attach to the leading edges of swept

wings and some control surfaces.

一次雷击至少有一个雷击引入点和一个放电点。飞机不可能存储闪电的能量。飞机的各个尖点是典型的初始雷击点和放电点，这些尖点包括：雷达罩、翼尖、升降舵和方向舵的尾部、凸起的天线以及发动机。雷击也可能产生于后掠翼和控制面的前缘。

FAR 25.581 “…aircraft must be protected

against catastrophic effects of lightning…”

• Lightning damage protection integrated into

design

飞机的外部结构主要是金属，这为飞机的防雷击提供了基本的保护。金属的外表结构就像一个防护罩一样，在飞机遭受雷击时能传导很大的电流，因而能保护内部的舱体。然而，对于不导电的外部复合材料结构，我们为其设计了防护系统以形成导电路径，从而减少雷击损伤。

The airplane configuration is primarily metal external structure, and this

provides

the airplane’s basic protection. The metal surface acts as a shield to conduct the

heavy electrical currents flow during a lightning strike, thus preventing damage to

the internal compartments. However, for non-conductive external composite parts,

protection schemes are built into them to complete the conductive path to reduce

lightning strike damage.

飞机的外部结构主要是金属，这为飞机的防雷击提供了基本的保护。金属的外表结构就像一个防护罩一样，在飞机遭受雷击时能传导很大的电流，因而能保护内部的舱体。然而，对于不导电的外部复合材料结构，我们为其设计了防护系统以形成导电路径，从而减少雷击损伤。

Goal

• Maintain structural integrity

• Avoiding more expensive repairs by early

detection

• Find at least two damage locations

• Initial attachment point

• Exit point

• Post strike inspection procedures provided

in AMM Chapter 5

Lightning strike damage might include but is not limited to the following

indications.

For metallic structures: holes, pits, burned or discolored paint.

For composite structures: missing or delaminated plies, burned or discolored paint.

Post lightning strike conditional inspection information can be found in AMM

Chapter 05-51.

目标：

维护结构完整性

早期检测以避免更昂贵的维修费用

找出至少两个损伤点：

初始雷击点（即雷击引入点）

放电点

雷击后的检测程序请参见AMM 第5章

Lightning strike damage might include but is not limited to the following

indications.

For metallic structures: holes, pits, burned or discolored paint.

For composite structures: missing or delaminated plies, burned or discolored paint.

Post lightning strike conditional inspection information can be found in AMM

Chapter 05-51.

雷击损伤常有以下表现形式（但不限于这些形式）：

对于金属结构：穿孔、凹坑、漆层燃烧或变色

对于复合材料：分层或掉块、漆层燃烧或变色

雷击之后的各种情况检测信息请参见AMM51章51节。

At times the lightning strike damage may be noticeable only as a pit or small hole

adjacent to a fastener as shown here.

有时，雷击损伤点只是紧固件旁边的一个凹点或小孔，如图所示。

This is an example of lightning strike damage to a fuselage skin. Note the missing

material adjacent to the fastener hole. This is caused by the high temperature

resulting from the lightning strike. This melting indicates the temperature reached

1200F (the melting point of 2024 aluminum) momentarily during the strike. The

cross-section shows that the aluminum microstructure adjacent to the melted area

consists of a very shallow, ~ 500 micron thick, re-cast microstructure (darkened

portion). Further examination of this cross-section shows the aluminum skin has a

normal microstructure, i.e. undamaged, only about 0.04 inch from the heat affected

area.

这是一个机身蒙皮遭雷击的例子，请注意紧固件孔旁边的空洞。这是由雷击引起的高温导致的。熔化的金属表明，在雷击发生时温度高达1200F（这是2024铝金属的熔点）。在剖面图中可以看到，在熔化区域周围的铝结构中有一个非常窄小的，大约只有500微米厚的重涛结构（变黑部分）。进一步检查表明，距离受热影响区域之外的0.04英寸的铝蒙皮的结构没有变化，也就是没有受损！

In this incident, the operator reported that even though the discoloration seemed to

be very extensive and intense, electrical conductivity results indicated that the

actual material damage area was confined to a very small area.

在该事件中，营运人报告说，虽然变色的范围很大，而且很严重，但事实表明实际的材料损伤范围很小。

General SRM repair options for lightning strike

• Blend-out damage

• Install rivet

• Small hole flush repair (\"Dollar-dime\" repair)

• Small hole external repair

• SRM repairs being modified to include damage at

and adjacent to factory installed fasteners,

minimum NDT requirements, and the use of blind

fasteners

对于雷击的一般修理方法（SRM）

去除损伤部分

安装铆钉

小孔平补（硬币式补法）

小孔外补

SRM中的修理方法经改进后可适用于紧固件孔和紧固件孔边缘的损伤修理，一般无须无损探伤，可用拉钉。

The 777 SRM has a repair procedure in Chapter 53-00-01 Repair 8 - Repair for

Lightning Strike or Small Hole Damage in the Pressurized Fuselag

波音777的SRM53-00-01“REPAIR 8”中有关于增压区蒙皮雷击损伤和小孔损伤的修理步骤。

See Chapter 53 of the SRM for further information on this repair.

该修理方法的更多信息请参见SRM53章

• Fastener Allowable Damage

• Permit small damage on fastener heads and adjacent skin

• Heat Damage

• Permit flight with suspect localized heat damage up to 0.5

inch in diameter on the fuselage skin

– Applicable to 777 and 737 Classic/NG models only (Not

currently an issue on other models)

• 10X Visual

• Permit as part of minimum repair steps until more

vigorous HFEC inspection can be accomplished

• Blind Fasteners

• Permit use at damaged factory installed and new fastener

locations (Time limited repair with repeat inspections)

紧固件损伤容限

在钉头上和附近的蒙皮上允许小面积损伤

受热损伤

在机身蒙皮上允许最大0.5英寸的受热损伤

----只适用于777和737老式/新式机型

10倍放大镜目视

对于轻微的修理可仅用10倍放大镜目视检查,较严重的用高频涡流探伤

拉钉

在受损的钉孔位置可用拉钉堵孔(但仅为时限修理,而且需定期检查)

Typical Damage Locations (see AMM

for further instructions)

• Radome

• Wing tips

• Stabilizer tips

• Elevator

• Rudder

• Aileron

• Wing-to-body fairings

• Nacelles

典型损伤位置（详见维护手册）

雷达罩

翼尖

水平安定面尾部

升降舵

方向舵

副翼

机翼-机身整流罩

吊架

Lightning strike protection materials are applied to the surfaces of composite parts

that may be exposed to lightning strikes. Composite materials need lightning strike

protection because they have a low electrical and thermal conductivity. The

protection system decreases the amount of localized burning and delamination

damage.

The radome is an area of special concern for lightning protection. A protective

layer cannot be used due to the transmission requirements of the radar installed

inside the radome. Protection is provided by the application of diverter strips on the

outside surfaces. The strips can be either in the form of solid metal bars or a

series

of closely spaced buttons of conductive materials affixed to a plastic strip.

易遭雷击的复合材料部件表面有雷击保护材料。复合材料之所以需要雷击保护是因为它们的导电性和导热性低，保护层可以减轻复合材料的烧伤和分层损伤。

雷达罩是雷击保护特别注意的地方。由于雷达罩里面的雷达须要传送信号，因此在雷达罩上不能使用保护层。它由安装在外表面的导电条进行雷击保护。这些导电条可以是实心的金属条，也可以是由紧挨在一起的导电性小颗粒粘附在塑料条上做成。

Goals

• Electrically critical component

– Prevent damage to wires, electrical

components, fuel vapor zones, or antennas

• Electrically non-critical component

– Reduce the extent of damage to panel only

目的：

对于关键部位

--防止电线、电子设备、燃油蒸汽区域、天线等的损伤

对于非关键部位

--只为了减少损伤的程度

Aluminum picture frames

• Flame-sprayed aluminum

• Aluminum foil

• Metal mesh

• Aluminum

• Copper

采用铝框

火焰喷涂铝

铝薄纸

金属网格

铝金属网格

铜金属网格

The aluminum picture frame is added to parts such as rudders and elevators as an

alternative to flame-sprayed aluminum coatings. The picture frame is normally

attached to the surface of the composite part using BMS 5-95 sealant. In

addition,

several fasteners passing through the picture frame are used to connect it to the

grounding paths in the underlying metallic structures. Similar grounding fasteners

are found on structures that are protected with flame-sprayed aluminum.

在方向舵和升降舵等部件上加上铝框以代替火焰喷涂铝。铝框通常用BMS5-95装于复合材料表面。另外，还要用一些紧固件将铝框和里面的由金属材料组成的接地装置连接起来。在用火焰喷涂铝保护的结构上也要用到类似的接地紧固件。

Discolored or missing

paint

• Burned, punctured, or

delaminated skins

• NDT indicates core or

inner skin damage

• Frayed fibers

• Missing skin plies

变色或漆层脱落

烧伤、击穿或分层

芯部或内部蒙皮受损（用NDT方法检测）

纤维断裂

外层板丢失

Besides visual indications of a lightning strike, non-destructive testing (NDT) is

used to detect hidden damage inside a composite part. The NDT Manual, Part I, 51-

01-03 has inspection procedures for hidden damage that is not visible on the part

surface. Most lightning damage repairs require restoration of structural skin plies.

In some cases, SRM allowable damage limits for holes or delaminations may allow

repairs to be deferred until the next maintenance visit. However, it is important to

seal the area to prevent the possibility of moisture ingression until a repair is made.

The repair procedures for damaged composites are found in the SRM.

有些雷击损伤目视就可以看出，而复合材料内部的损伤则需要用无损探伤的方法检测。对于在外表面无法看到的内部损伤的检测程序请参见《无损探伤手册》第I部，51-01-03。大多数的雷击损伤要求修复结构表层。在有些情况下，《结构修理手册》损伤容限范围内的孔或分层允许推迟修理。但是必须注意做好该区域的密封工作以防止水份的侵入。复合材料损伤的修理程序请参见《结构修理手册》。

Same elevator as previous slide. This one shows damage on forward

surface of aft spar.

与前一张图同一个升降舵。本图所示为后梁前侧的损伤。

Lightning usually causes damage in two areas, the point of initial impact and the

exit, or point of discharge.

雷击通常会引起两个地方的损伤，一个是雷击初始点（即电流进入点），另一个是放电点（即电流流出点）

These pictures illustrate lightning damage on a composite elevator, along with

damage on the outboard wing tips. When flight controls show evidence of lightning

damage, examine the hinges, bearings and bonding straps for signs of damage.

Also, functional testing is required.

这些图所示的是升降舵复合材料的损伤和翼尖外缘的损伤。当遭到雷击时，请检查铰链、轴承和粘接带是否有损伤，而且要做功能测试。

Visual Inspection

• Check and restore ground paths

• Check conductivity after repair

目视检查

检测并修复接地线路

检查修理之后的导电性

In addition to checking for lightning strike damage, all grounding paths should be

checked after a strike and periodically at maintenance checks to ensure protection

schemes will function correctly during a strike.

在雷击之后以及在定期检修之时，除了要检查雷损伤情况以外，还要检查接电线路是否畅通，以确保飞机在遭到雷击时雷击保护装置能起到作用。

SRM provides allowable damage and repair

procedures on

• Flame-sprayed aluminum

• Expanded metal mesh

• Aluminum foil

• Speed tape can be used on time-limited basis

《结构修理手册》提供了以下材料的损伤容限和修理程序：

火焰喷涂铝

金属网格

铝薄纸

在做时限修理时，可以使用胶带

Repair procedures for composite panel lightning strike protection materials can be

found in SRM Chapter 51-70-14.

复合材料面板雷击保护材料的修理程序请参见《结构修理手册》51-70-14。

The aluminum speed tape repair is a quick and inexpensive repair method that can

be used on electrically critical and non-critical fiberglass panels. In some repairs, it

is important to perform a continuity check of the repair prior to putting airplane

back into service to assure that the repaired area will maintain electrical continuity

to the rest of the panel surface. This check is important for applications that use the

coating for p-static dissipation

This is a section view of a composite part that incorporates the optional speed tape,

flame spray repair. The repair materials used are adhesive backed aluminum tape

(speed tape), BMS 5-92 paste adhesive, sealant (preferably BMS 5-26) and non

adhesive backed aluminum foil.

铝簿胶带修理是一种快速且廉价的修理方法，它可以用在重要的电子部件和非重要的纤维玻璃面板上。在有些修理中必须记住：在飞机投入使用之前必须做导电性检测以确保被修理部位和面板表面的其它部位保持导电连续性。对于使用构件表面来消除静电的地方，这种检测尤为重要。

本图是用快粘胶修复火焰喷涂表面的复合材料剖视图。修理材料包括：铝薄胶带、BMS5-92、密封胶（最好用BMS5-26）以及不带粘性的铝簿纸。

Restore structure and protection systems after

a lightning strike

• Post strike instructions provided in maintenance

manual Chapter 5

• Common repairs incorporated in SRMs using 777

SRM as baseline

雷击之后须恢复结构和雷击保护系统

雷击之后的处理办法请参见维护手册第5章

结构修理手册中的通用修理方法以波音777机型为基础