# SDR CALA2026042215596

- Type: Service difficulty report (as reported; unverified)
- Difficulty date: April 20, 2026
- Submitted: April 22, 2026
- Operation: Air carrier
- Aircraft: [N77588](https://openairdocs.org/aircraft/N77588), registered now
- Make and model: Boeing 737-9
- Registry model: [Boeing 737-9](https://openairdocs.org/model/boeing-737-9) (OpenAirDocs)
- Aircraft serial: 43446
- Aircraft time: 5,190 hours, 1,681 cycles
- System (JASC): [3830 · Waste Disposal System](https://openairdocs.org/jasc/3830)
- Part: Control Module
- Part number: 1742F9
- Part serial: 3766
- Condition: Faulty
- Location: Zone 900
- Part time: 5,177 hours, 1,678 cycles
- Stage of operation: CR
- How discovered: O
- Nature of condition: J
- Precautionary procedure: A
- FAA source: FAA Service Difficulty Reporting System (https://sdrs.faa.gov/)
- Page: https://openairdocs.org/sdr/CALA2026042215596

## Discrepancy

CREW REPORTED ALL TOILETS WOULD NOT FLUSH AIRBORNE FOUND CB C11 VACUUM WASTE CONT OPEN ON P91 PANEL SEE PICTURE ATTACHED RESET CB. ALL LAVS FLUSH ON GROUND WITH NO BREAKER TRIP. VACUUM PRESSURE IS GOOD RULING OUT CLOGGED FILTER. POSSIBLE ISSUE WITH BAROMETRIC ALTITUDE SWITCH, S1033, SINCE PROBLEM OCCURS IN AIR. DUE TO EXTENSIVE HISTORY AND DIVERSION, SUGGEST ALSO CHANGING LOGIC CONTROL MODULE AND VACUUM CONTROL RELAY, R581. REF. FIM 38-32 TASK 803 REPLACED R581 VACUUM WASTE CONTROL RELAY REF SSM38-32-12-104 & AMM24-51-11. PARTS USED:  29-2450-3-0006,QTY :1 ADD EMP:U380167 REMOVED AND REPLACED VACUUM BLOWER BAROMETRIC SWITCH IN REFERENCE WITH AMM 38-32-12. REMOVED AND REPLACED LOGIC CONTROL MODULE IN REFERENCE WITH AMM 38-33-03. OPS CHECKS GOOD ON ALL COMPONENTS. AIRCRAFT OK FOR SERVICE. PARTS USED: 99-3832-3-0059,QTY :1  99-3833-9-0002,QTY :1 MFG PN ON - 1742F9 MFG SN ON - 32162 M&E SN ON - 02162 M&E PN ON - 99-3833-9-0002 MFG SN OFF - 33766 MFG PN OFF - 1742F9 ROTABLE PARTS CHG:TT # 1286547 SN OFF 3766 PN OFF 99-3833-9-0002 UNIT, ASSY LOGI  OFF 99-3833-9-0002 3766 ON 99-3833-9-0002 2162

---
OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. Source documents are U.S. government works in the public domain.