A Southwest 737 crew returned for an immediate landing, after facing an electrical problem that left them with only minutes of battery power.
The incident happened on the 25th of October. It involved Southwest flight WN-1812, from Phoenix Sky Harbor International (KPHX) to Dallas Love Field (KDAL) in the United States. The flight had 183 people on board, and lifted off at 7:03 am local time, from runway 07L. But very soon, the crew started facing problems.
Air Traffic Control inquired the Southwest crew about their altitude. They responded that they were dealing with an electrical fault, which was why their altitude wasn’t showing. It appears that the Southwest 737 was on standby power, using its battery. In this mode, several systems don’t get any power, including the transponder signal that sends the aircraft’s altitude to ATC.
Southwest 737 – Running On Battery Power
The Southwest crew requested to continue their departure while attempting to restore their electrical systems, still on battery power. ATC cleared them first to 8,000 feet. And soon afterwards, the flight was cleared to FL210. But the crew requested to maintain 8,000 feet. It is not clear what altitude the flight actually reached. Tracking websites show their GPS altitude at 2,850 feet; others suggest they reached 7,300 feet.
But it doesn’t matter. The flight crew eventually declared an emergency, requesting an immediate return to Phoenix. At this time, the Southwest 737 only had 25 minutes of battery power left, according to the crew. So they positioned the jet for a visual return, landing safely on runway 08. In total, the flight only lasted approximately 16 minutes.
The flight’s passengers eventually made it to Dallas on a different 737-800, with a three-hour delay. And interestingly, the Southwest 737 in this incident returned to service only 5 hours after running on battery power only. This is a 737-8H4(WL), with tail number N8657B. It is just under 7 years old, having its first flight in December 2014.
The aircraft continued its service normally, actually being in the air as of this writing. It is not clear if the FAA will investigate this event further.