579857
65
Zoom out
Zoom in
Previous page
1/412
Next page
190-01007-A3 GTN 6XX/7XX AML STC Installation Manual
Rev. 4 Page 2-23
the antenna’s susceptibility to RF radiation from components inside the aircraft.
2.4.5 Electrical Bonding
Electrical equipment chassis, shield/ground terminations, antennas, supporting brackets, and racks must
be electrically bonded to the aircrafts main structure (metallic or tube/fabric aircraft) or instrument panel
(composite aircraft). Refer to SAE ARP 1870 Section 5 when surface preparation is required to achieve
electrical bond. The electrical bond must achieve direct current (DC) resistance less than or equal to:
2.5 milliohms to local structure in equipment mounting locations for metallic or tube and fabric
aircraft.
5.0 milliohms to the instrument panel for composite aircraft.
For some aircraft the instrument panel is attached with vibration mounts. For these aircraft, it must be
verified that the vibration-isolated instrument panel is grounded to the airframe metallic structure with a
bonding jumper the same or equivalent to the specification below. If no such jumper is installed, a
bonding strap meeting the following criteria must be installed to accomplish this:
The cross sectional area of the strap must be greater than 0.016 square inches (approx 20800
circular mils). A 7/16 inch or wider tubular braid (QQB575R30T437, 24120 circular mils) or a
3/4 inch or wider flat braid (QQB575F36T781, 20,800 circular mils) must be used.
The strap length should be as short as possible and must not exceed 6 inches. Detailed design of a
bonding strap meeting these requirements is shown in Section 3.6.8.
Compliance must be verified by inspection using a calibrated milliohm meter.
The antenna ground plane must be electrically bonded to the antenna baseplate. The electrical bond must
achieve direct current (DC) resistance less than or equal to 2.5 milliohms. Do not remove paint on outer
skin of aircraft under the footprint of the antenna baseplate unless necessary to meet bonding
requirements. The painted surface prevents corrosion and should be left intact if possible.
Brackets installed to main structure or instrument panel with four or more rivets can provide sufficient
electrical bond to allow equipment chassis or equipment rack to be bonded to the bracket. More rivets or
surface preparation may be needed for brackets that will carry large DC/AC or lightning currents.
The correct material finish is important when mating untreated or bare dissimilar metals. They should be
galvanically compatible. When corrosion protection is removed to make an electrical bond any exposed
area after the bond is completed should be protected again. Additional guidance can be found in
AC 43.13-1B and SAE ARP1870.
Typical electrical bonding preparation examples are shown in Figure 2-8, Figure 2-9, and Figure 2-10.
Aluminum surface preparation is detailed in Section 2.4.5.1.
2.4.5.1 Aluminum Surface Preparation
To prepare an aluminum surface for proper bonding, this general procedure should be followed. For a
more detailed procedure, reference SAE ARP1870 Sections 5.1 and 5.5.
1. Clean grounding location with solvent.
2. Remove non-conductive films or coatings from the grounding location.
3. Apply a chemical conversion coat such as Alodine 1200 to the bare metal.
4. Once the chemical conversion coat is dry, clean the area.
5. Install bonding aluminum tape or equipment at grounding location.
6. After the bond is complete, if any films or coatings were removed from the surface, reapply a
suitable film or coating to the surrounding area.
65


Need help? Post your question in this forum.

Forumrules


Report abuse

Libble takes abuse of its services very seriously. We're committed to dealing with such abuse according to the laws in your country of residence. When you submit a report, we'll investigate it and take the appropriate action. We'll get back to you only if we require additional details or have more information to share.

Product:

For example, Anti-Semitic content, racist content, or material that could result in a violent physical act.

For example, a credit card number, a personal identification number, or an unlisted home address. Note that email addresses and full names are not considered private information.

Forumrules

To achieve meaningful questions, we apply the following rules:

Register

Register getting emails for Garmin GTN 650 at:


You will receive an email to register for one or both of the options.


Get your user manual by e-mail

Enter your email address to receive the manual of Garmin GTN 650 in the language / languages: English as an attachment in your email.

The manual is 8,92 mb in size.

 

You will receive the manual in your email within minutes. If you have not received an email, then probably have entered the wrong email address or your mailbox is too full. In addition, it may be that your ISP may have a maximum size for emails to receive.

The manual is sent by email. Check your email

If you have not received an email with the manual within fifteen minutes, it may be that you have a entered a wrong email address or that your ISP has set a maximum size to receive email that is smaller than the size of the manual.

The email address you have provided is not correct.

Please check the email address and correct it.

Your question is posted on this page

Would you like to receive an email when new answers and questions are posted? Please enter your email address.



Info