# SDR ASAA2020022422237

- Type: Service difficulty report (as reported; unverified)
- Difficulty date: February 22, 2020
- Submitted: February 24, 2020
- Operation: Air carrier
- Aircraft: [N557AS](https://openairdocs.org/aircraft/N557AS), registered now
- Make and model: Boeing 737890
- Aircraft serial: 35176
- Aircraft time: 52,327 hours, 15,253 cycles
- System (JASC): [2421 · AC Generator-Alternator](https://openairdocs.org/jasc/2421)
- Part: Electrical Sys
- Condition: Malfunctioned
- Location: Apu
- Stage of operation: NR
- How discovered: O
- Nature of condition: H, J
- Precautionary procedure: O
- FAA source: FAA Service Difficulty Reporting System (https://sdrs.faa.gov/)
- Page: https://openairdocs.org/sdr/ASAA2020022422237

## Discrepancy

WITH THE APU SUPPLYING ELECTRIC POWER WITH THE APU GENERATOR THE VOLTS AND FREQ DROPPED TO ZERO THEN RETURNED TO NORMAL. GROUNDED - YES. PERFORMED APU GCU BITE REF B737-800 FIM 24-21 TASK 801, NO FAULTS FOUND. ALSO PERFORMED APU BITE WITH CDU REF B737-800 AMM 79-61-00-700-801, NO FAULTS FOUND. OPERATED APU GENERATOR REF AMM 49-11-00-710-801, OPS CHECK GOOD NO DEFECTS NOTED.

---
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.