Shortly after Southwest Airlines made headlines for its $10.2-million fine by the FAA for continuing to fly more than 100 of its planes after missing mandatory safety checksand facing the pressure of the FAA's increased maintenance record auditingseveral major airlines grounded planes to conduct new inspections.The most recent carrier to do so was American Airlines (AA), which was asked by the FAA to ground its MD-80 fleet for the second time on April 8, canceling about 3,000 flights by the time planes returned to flight on April 13. The airline had previously voluntarily halted flights on its 300 MD-80 planes for two days in March. Also on April 8,Alaska Airlines grounded its nine MD-80s.On April 2,United Airlines took all 52 of its Boeing 777 jets out of the air for tests. In a statement, the airline said, "As part of a regular review of maintenance records, the company discovered that the functional test that checks the firing system on one of the five bottles in the cargo fire suppression system on the Boeing 777 was not performed, and this was voluntarily disclosed to the FAA. United is in the process of checking this part of the system." The company further stated, "United will not operate these aircraft until the tests are complete." The airline offered travel waivers to affected customers and waived certain flight change fees.A week earlier, Delta Air Lines grounded 177 MD-88 planes. Both Delta and United had the planes back in the skies within 48 hours. While the grounded planes only affected a small portion of the airlines' total number of scheduled flights, passengers were left battling delays and cancellations.In a statement on Delta.com, Steve Gorman, executive vice president of operations, stated, "Though these re-inspections impacted the travel plans of many of our customers, safety is our number-one priority and conducting these inspections proactively was the right decision."Originally published April 21, 2008