DOC AIRBUS | AMM A320FInspection of the DME antenna
TASK 34-51-11-200-801-A
Inspection of the DME antenna
1. Reason for the Job
To define the acceptability criteria of the damages on the DME antennas due to environmental exposure.
2. Job Set-up Information
A. Fixtures, Tools, Test and Support Equipment
B. Consumable Materials
C. Work Zones and Access Panels
D. Referenced Information
3. Job Set-up
Subtask 34-51-11-865-061-A
Subtask 34-51-11-210-050-A
[Rev.10 from 2021]
2026.04.02 06:23:30 UTC
Inspection of the DME antenna
1. Reason for the Job
To define the acceptability criteria of the damages on the DME antennas due to environmental exposure.
2. Job Set-up Information
A. Fixtures, Tools, Test and Support Equipment
| REFERENCE | QTY | DESIGNATION |
|---|---|---|
| No specific | AR | SAFETY CLIP - CIRCUIT BREAKER |
| REFERENCE | DESIGNATION |
|---|---|
| (Material No.08BAA9) | Non Aqueous Cleaner-General - - |
| (Material No.14SBA1) | Textile-Lint free Cotton - |
| ZONE/ACCESS | ZONE DESCRIPTION |
|---|---|
| 120 | AVIONICS COMPARTMENT |
| 130 | FWD CARGO COMPT AFT BULKHEAD OF AVNCS COMPT TO FWD PRESSURE BULKHEAD OF WING CENTER BOX |
| REFERENCE | DESIGNATION |
|---|---|
| TASK 34-51-00-710-001-A | Operational Test of the DME |
| TASK 34-51-11-000-002-A | Removal of the DME Antenna |
| TASK 34-51-11-400-002-A | Installation of the DME Antenna |
LIGHT EROSIONSubtask 34-51-11-865-061-A
A. Open, safety and tag this(these) circuit breaker(s):
Subtask 34-51-11-100-050-A | PANEL | DESIGNATION | FIN | LOCATION |
|---|---|---|---|
| ** ON A/C ALL | |||
| FOR FIN: 3SD1 (ANTENNADME, 1) | |||
| 49VU | NAV/DME/1 | 1SD1 | G14 |
| FOR FIN: 3SD2 (ANTENNADME, 2) | |||
| 121VU | COM NAV/DME/2 | 1SD2 | K06 |
B. Inspection of the area
(1) FOR [3SD1] (ANTENNA-DME, 1)
You can find DME 1 antenna at zone 120.
Make sure that the inspection area is sufficiently clean to do a satisfactory inspection of the area.
(2) FOR [3SD2] (ANTENNA-DME, 2)
You can find DME 2 antenna at zone 130.
Make sure that the inspection area is sufficiently clean to do a satisfactory inspection of the area.
(3) If not, clean the inspection area with Non Aqueous Cleaner-General - - (Material No.08BAA9) and a clean Textile-Lint free Cotton - (Material No.14SBA1) .
4. Procedure(1) FOR [3SD1] (ANTENNA-DME, 1)
You can find DME 1 antenna at zone 120.
Make sure that the inspection area is sufficiently clean to do a satisfactory inspection of the area.
(2) FOR [3SD2] (ANTENNA-DME, 2)
You can find DME 2 antenna at zone 130.
Make sure that the inspection area is sufficiently clean to do a satisfactory inspection of the area.
(3) If not, clean the inspection area with Non Aqueous Cleaner-General - - (Material No.08BAA9) and a clean Textile-Lint free Cotton - (Material No.14SBA1) .
Subtask 34-51-11-210-050-A
A. Definition of the different damages
(1) There are 3 categories of damages.
The antenna is affected by a light impact or superficial corrosion that can compromise its structural integrity. This kind of damage can be detected through a visual inspection because it is associated to debris or pebble impacts or corroded areas:
Erosion is the wear process whereby the antenna gradually loses the paint layers. Erosion can be mechanical, due to the friction of the antenna with air, dust and fine particles that lead to paint wear and, if no correction is applied, even to the structure wear with detrimental effects. Erosion can also be chemical due to reactions that may attack the paint. If it is not solved it may lead to corrosion once all the paint layers are worn and the metallic elements are exposed. Two degrees of erosion can be defined:
Subtask 34-51-11-200-050-A Subtask 34-51-11-750-050-A (1) There are 3 categories of damages.
- Critical Damage
- Deep Erosion
- Light Erosion
The antenna is affected by a light impact or superficial corrosion that can compromise its structural integrity. This kind of damage can be detected through a visual inspection because it is associated to debris or pebble impacts or corroded areas:
- In case of debris or pebble impact (mechanical aggression): this damage is generated by an isolated event that occurs between the (n-1)th and the nth inspections of the antenna so its trace is detected during the nth inspection while nothing was reported in the (n-1)th. The most typical traces detected are:
-an area with detached paint (finish or primer layers) with well-defined edges
-a dent, deformation or cracked area
If the 1st inspection (n=1) of impacts is done on a non-new antenna, there is no reference of (n-1)th inspection. In this case, if an area is suspected to be affected by a debris or pebble impact, it shall be considered as critical damage.
The debris or pebble impact must not be confused with collisions – with a land vehicle or big object. Collisions generate directly a detrimental damage of the antenna and requires its immediate replacement before a new flight.
Erosion is the wear process whereby the antenna gradually loses the paint layers. Erosion can be mechanical, due to the friction of the antenna with air, dust and fine particles that lead to paint wear and, if no correction is applied, even to the structure wear with detrimental effects. Erosion can also be chemical due to reactions that may attack the paint. If it is not solved it may lead to corrosion once all the paint layers are worn and the metallic elements are exposed. Two degrees of erosion can be defined:
C. Deferral rules
This table provides the deferral rules:
During the grace period, the antennas must be inspected each day when a flight is scheduled to make sure that the degree of damage remains the same.
If there is damage as described in the Table 1, make an entry in the logbook.
If a degradation of the damage is detected, a new analysis must be performed related to the criteria of chapter §4.A and taking into account the start of the initial grace period. This means that the number of FC or days counted since the first damage detection must not be reset and the grace period of the new type of damage must be applied.
Subtask 34-51-11-865-062-A This table provides the deferral rules:
| Type of damage | Grace period |
| Dangerous damage | Antenna to be replaced before 1 day |
| Depth of erosion | Antenna to be replaced before 50 FC or 10 days (the one that occurs first) |
| Light erosion | Antenna to be replaced before 100 FC or 20 days (the one that occurs first) |
If there is damage as described in the Table 1, make an entry in the logbook.
If a degradation of the damage is detected, a new analysis must be performed related to the criteria of chapter §4.A and taking into account the start of the initial grace period. This means that the number of FC or days counted since the first damage detection must not be reset and the grace period of the new type of damage must be applied.
D. Close this(these) circuit breaker(s):
Subtask 34-51-11-710-050-A | PANEL | DESIGNATION | FIN | LOCATION |
|---|---|---|---|
| ** ON A/C ALL | |||
| FOR FIN: 3SD1 (ANTENNADME, 1) | |||
| 49VU | NAV/DME/1 | 1SD1 | G14 |
| FOR FIN: 3SD2 (ANTENNADME, 2) | |||
| 121VU | COM NAV/DME/2 | 1SD2 | K06 |
E. Operational Test
The operational test of the system associated to the antenna must be correct in accordance with the corresponding task instruction in the following cases. (Ref. AMM TASK 34-51-00-710-001)
Subtask 34-51-11-960-050-A The operational test of the system associated to the antenna must be correct in accordance with the corresponding task instruction in the following cases. (Ref. AMM TASK 34-51-00-710-001)
- At the beginning of the grace period, when the environmental damage is detected for the first time, before the first dispatch allowance.
- During the grace period, if a quick degradation of the damage is detected and the type of damage evolves to a more critical one based on the criteria of chapter §4.A and following the rules defined in §4.C before the next dispatch allowance.
F. Replacement of the antenna
At the end of the grace period, replace the antenna. (Ref. AMM TASK 34-51-11-000-002) (Ref. AMM TASK 34-51-11-400-002)
At the end of the grace period, replace the antenna. (Ref. AMM TASK 34-51-11-000-002) (Ref. AMM TASK 34-51-11-400-002)