AOA Service Instructions


AOA Service Instruction 0210
Date: October 10, 2002
Subject: AOA Pro II recall
Models Affected: Serial Number 650 through 672
Time of Compliance: upon Receipt

Background:
A batch of Pro II AOA printed circuit boards were manufactured using a new environmentally friendly soldering and cleaning process. Water soluble pastes used in the manufacturing process may not have been thoroughly removed and may have contaminated the pressure sensors. Inspection of these parts requires a test and possible removal and cleaning of the pressure sensor.

Action:
Some AOA Pro CPUs shipped between April and September, 2002 with a serial numbers of 650 through 672 are affected by this recall. The serial number is found on the black sticker located on top of the CPU.

Please return the CPU to Proprietary Software Systems, Inc. for inspection and re-cleaning if necessary. Please ship only the CPU via ground and insured for $500 to Proprietary Software Systems, Inc, 950 Iris Circle, Excelsior, MN 55331. If the CPU is removed from an aircraft and the aircraft is airworthy, you must plug the open red and clear pitot/static tubes while the modification is in progress to prevent pitot/static errors.



AOA Service Instruction 0201
Date: January 29, 2002
Subject:
RV Pre-Calibrated Chips for Van's Aircraft
Models Affected: All AOAs for RVs with pre-calibarated data installed
Time of Compliance: upon Receipt

Background:
For AOAs with RV pre-calibrated data, it is important to get the flap switch wired properly so that it matches the flaps up/down data stored in the calibration chip. All RV customers that have received pre-calibrated data should comply with this service instruction. The RV calibration chips are formatted differently after January 29, 2002 for standardization with the general manual instructions.

Action:
For AOAs or EEPROMS shipped prior to January 29, 2002 or with Sport Serial numbers of 568 or less except 526, 532 and 557-561. When the flaps are down confirm that the flap switch electrical contacts are open. When the flaps are up, confirm that the electrical contacts of the flap switch are closed. This is easily accomplished by using a resistance meter. If this is not the case, move the wire labeled FLAP to the other lug of the flap switch and retest.

For AOAs or EEPROMS shipped after January 29, 2002 or with a serial number of 569 or greater or 526, 532 and 557-561. When the flaps are down confirm that the flap switch electrical contacts are closed. When the flaps are up, confirm that the electrical contacts of the flap switch are open. This is easily accomplished by using a resistance meter. If this is not the case, move the wire labeled FLAP to the other lug of the flap switch and retest.

For all RV installations

Use the Verification Checklist to confirm the calibration data is correct for your aircraft. This checklist is enclosed or may be downloaded from our web site at www.angle-of-attack.com. Click on the FTP download link and get the file labeled "Calibrate Verify CL". Download instructions for users of MS Internet Explorer are also available from our web site.



AOA Service Instruction 0108
Date: August 31, 2001
Subject: AOA Sport Hardware
Models Affected: Some AOA Sports shipped between July 20 and August 31, 2001
Time of Compliance: Prior to September 30, 2001 or prior to flight which ever occurs first

Background:
Some pressure sensors were soldered to the AOA circuit board using an incorrect solder flux. The Sport serial numbers that may be affected are 500-502, 505-511, 514, 518-522, 525 and 527-528.

Action:
The solder flux must be cleaned from the circuit board.

Remedy:
Please return the CPU (brain box) insured for $500 for these modifications to the below address. Your assistance will be greatly appreciated as we strive to provide a quick turn and good customer support. Please include within the shipment a copy of this service instruction, a return shipping address and telephone number. Also, include the type aircraft for our records. If your aircraft is flying, you must plug the open red and clear pitot/static tubes while the modification is in progress to prevent pitot/static errors.



AOA Service Instruction 0011
Date: November 3, 2000
Subject: AOA Hardware/Software Modification
Models Affected: Some AOA Professionals in noisy environments with version 3-8 software and Group 4 and 5 EEPROMS
Time of Compliance: Upon the issuance of an ERROR 13 message

Background:
Two field reports indicate that the EEPROM memory chip’s flaps down database became corrupted after several months of normal service. Error message "ERROR 13" sounded during power up, when pushing the push to test button, and during flap selection to down. This problem has been isolated to SX-300 aircraft to date but could affect others. This error message is issued when the check sum stored in the chip does not match the computed check sum. We expect that this service instruction will affect very few customers since the problem is aircraft installation specific.

The problem was particularly confounding due to the coincidence that both occurred in the same type aircraft. However, it was discovered that 93 series Group 4 and 5 EEPROMS used in some AOA Professionals operate at a higher speed internally thus are more susceptible to noise than the original 93 series EEPROMs shipped in earlier AOAs. Noise is generally created during power up or down and the level and type of noise is aircraft specific. Consequently, a problem in one aircraft may not be a problem in another due to the different installation environment. Noise that causes these specific types of problems is difficult or impossible to duplicate in the lab.

The manufacturer of the memory chip issued an application note AN698 noting that memory location 7F on the Group 4 and 5 EEPROMs is subject to corruption under certain adverse conditions and suggested as a remedy installing a pull down on the chip select pin.

Action:
If your AOA was properly calibrated, has operated normally without error messages, and later issues an "ERROR 13" aural warning, your EEPROM data has become corrupted during a system power up or down. The AOA must be returned for service. Note that an "ERROR 13" aural warning is normal if you have not yet properly calibrated your AOA.

Remedy:
Please return the CPU (brain box) insured for $500 for these modifications to the below address. Your assistance will be greatly appreciated as we strive to provide a quick turn and good customer support. Please include within the shipment a copy of this service instruction, a return shipping address and telephone number. Also, include the type aircraft for our records. If your aircraft is flying, do not forget to plug the open red and clear pitot/static tubes while the modification is in progress.

We will install the pull down if not already installed, and install a software modification, which avoids using memory location 7F all together. There is no charge for this modification and recalibration may not be required. If you have any questions regarding this service instruction, please call.



Service Instruction 9906
Date: June 14, 1999
Subject: Software and hardware update
Models Affected: AOA Sports shipped prior to June 1, 1999 with serial #1 through 50
Time of Compliance: At the next annual condition inspection or prior to January 2000 which ever occurs first.


Field reports indicate occasional nuisance on the ground "angle angle push" warnings. Although the nuisance warnings affect only a few installations, other minor changes to the software make the software upgrade significant enough to require that all AOA Sports be upgraded to Version 2 software. We will take this opportunity to upgrade the CPU hardware to be compliant with the latest hardware version which provides a third level of protection against AOA calibration data corruption. There is no charge for this hardware/software upgrade.

The new software does not change the calibration data that has been saved to non-volatile memory (EEPROM). Consequently, this software and hardware change will not require you to re-calibrate the AOA. A test flight is required to insure the AOA performs as before the upgrade.

AOA Sports with serial numbers 1 through 50 and or version 1 software shall be upgraded to Version 2 software and the PCBs hardware modified.

Proprietary Software Systems strives to provide only one hardware and one software version that performs properly regardless of aircraft type. We have been successful in this regard. Version 2 and the associated hardware change insures that the AOA Sport can be moved from one aircraft to another with only a re-calibration of the instrument to that particular aircraft.

Enhancements in software for Version 2 are:
-The software profile that cancels the "angle angle push" warning on the ground has been modified.
-The AOA display driver software turbulence filter has been relaxed slightly.
-RS-232 data stream was standardized to match the AOA Visual Basic PC Software used to interface the AOA Sport to personal computers.

This data interface option may be available to customers at a future date.
Please return just the CPU (brain box) insured for $500 for these modifications to the below address. Your assistance will be greatly appreciated as we strive to provide a quick turn and good customer support. Please include within the shipment a return shipping address. Also include the type aircraft for our records. If your aircraft is flying, don't forget to plug the pitot/static tubes while the upgrade is in progress.



Service Instruction 9904
Date: March 30, 1999
Subject: Software update
Models Affected: AOA Professionals shipped prior to December 31, 1998
Time of Compliance: At the next annual condition inspection or prior to January 2000 which ever occurs first.

Field reports indicate nuisance on the ground "angle angle push" warnings. Although the nuisance warnings affect approximately only one in twenty installations, other minor changes to the software make the upgrade significant enough to require that all AOA Professionals be upgraded to Version 7 software.

There is no charge for this software version when mailed to your address. The software comes preloaded on a chip. The new software does not change the calibration data that has been saved to the CPU. Consequently, software may be upgraded without the requirement to re-calibrate the AOA. A flight is required to insure the AOA performs as before.

AOA Professionals with Version 6, 5, or 4 shall be upgraded to Version 7.



Service Instruction 9809
For AOA CPU’s shipped prior to August 15, 1998 with a serial number of less than 125, remove a capacitor from the CPU by August 1999 or during your next annual inspection. This modification to the PCB is a part removal only. No replacement of C15 is required. After C15 removal a test flight of the aircraft is required to insure that a recalibration of the AOA is not required. C15 is located about 1/2 inch to the right of the tall metal encased oval shaped oscillator. "C15" is clearly silk screened on the PCB.

-Remove the top cover of the AOA CPU by removing four machine screws.
-Locate C15.
-Using a small wire cutter, cut both leads of C15 as close to the PCB as possible.
-Remove and disgard C15. (Now is a good time to make any minor adjustments to the AOA audio volume if required.)
-Replace the top cover of the AOA CPU.
-Replace and tighten the 4 cover screws.
-Test fly the aircraft to insure the angle advisory, optimum approach and landing gear warnings function properly in both the landing and cruise configuration. Recalibrate the AOA if necessary.
-In Appendix "H" of the AOA Manual initial and date the revision 2 box and indicate "SB9-98 C15 removal".
-If you have any questions or are not confident with doing the C15 removal, please call (612) 474-4154 for further instructions.