ATP Test Overview

Question 1

Commercial Nav Device Configuration

Answer 1

Controlling document order: 1st - Parts List, 2nd – Drawing

End Item (HG level) Parts List calls out the ATP that must be performed.

ATP is an ES drawing. Usually starts with ATPxxxx-xx but recent format is just a 66xxxxxx-xxx number.​

ATP base number is often used for a family of products.​

PL provides minimum Revision of ATP that must be used.

Question 2

ATP

Answer 2

Acceptance Test Procedure.
- Engineering Test Document called out on the PL’s.​
- Final manufacturing test required prior to shipment.​
- Serves as the Return to Service (RTS) test for RG’s.
- ATP document is an engineering document in Teamcenter.

Question 3

ATP Testing Approach

Answer 3

AH-1000 ATP incorporates a “Testing Functions” approach
- Isolate and test functions one at a time.​
- Easily map each ATP test to a Sub-assembly

Question 4

Guidelines for Determining Test Order

Answer 4

The functions most likely fail should be tested first. ​

Basic functions should be tested first. ​

Functions implemented in the same sub-assembly should be grouped together in the test sequence. ​

When trouble shooting a failed device, the first failure encounter in the test should be trouble shot and corrected before moving on to other failures.

Question 5

What should I understand in individual ATP tests?

Answer 5

Each “verify” in the Test Procedure paragraph becomes a GO/NOGO test.

Question 6

Understanding AH-1000 BITE

Answer 6

BITE:​ Built In Test Equipment​

The AH-1000 is continuously running tests on itself to ensure that it is operating without failures.

Question 7

4 Ways Fault Information is communicated

Answer 7

Fail Warning discrete – P/F indication.​

System Status Matrix in ARINC labels indicates if the data is suspect: Fail Warning, NCD, or passing​

Individual BITE Test bits in 270/271 labels​

Fault Records stored in the Event Log.

Question 8

AH-1000 BITE ARINC Labels

Answer 8

ARINC 270 & 271 Labels
- Communicate BITE status. Each bit in the label shows a Systems status or the results of a BITE test. ​
- Read multiple times during the ATP test.

Question 9

ARINC 270 Label

Answer 9

System Status – mostly not BITE.​
- AHRU Fault BIT​
- TAS Invalid – tell if ARINC Rx is working​
- Ext Config Data – tell if APM is working.​

Question 10

ARINC 271 Label

Answer 10

• Communicates internal BITE status. Each bit in the label shows the results of a BITE test. ​
• Read multiple times during the ATP test.

Question 11

ATP Run Sequence

Answer 11

Run at Cold, Hot & Room temperatures.​

Done for MSA, DMRS and AH-1000 MEMS devices because sensors are temperature calibrated at the device level. ​

4 MCU, LR6 and other RLG devices receive only at room temp ATP because their RLG’s and Accel’s are tested at temperature when they are manufactured.

Question 12

Trouble Shooting Tips

Answer 12

Decode which bits in the 270 & 271 labels are set and map them into most likely sub-assemblies as shown in the table above. The test program decodes the bits for you.​

Check the Event Log print out at the bottom of the test report. It should contain specific BITE test fault records that describe the failure. ​

Consider all the failure bits set and determine what is the most basic function that is failing. For example, a power supply problem should be detected and annunciated on Label 271, bit 22. But that power supply failure may also affect the Gyro or Accel cards causing their bits to get set as well.​

Look for correlation between the BITE failure and failures in tests that map to the same sub-assembly. If the Power Supply BITE is set, then look for other failures in the Power Supply test of the ATP.​

As always, trouble shoot the first failure encountered first.