2010-06 · NASA ASRS report 894922
A MD80's right generator tripped and AC CROSSTIE LOCKOUT activated inflight and did not reset according to QRH procedures. An emergency was declared; the aircraft descended to start the APU and divert. On the ground the engine generator and AC CROSSTIE LOCKOUT reset. The QRH procedure may be faulty.
While climbing through FL330 to cruise altitude of FL340 the autopilot and autothrottles disengaged; First Officer's flight instruments flagged; RH engine instruments froze in position; weather radar failed. I took over the controls and radios and First Officer accomplished the QRH procedures for a single system AC failure as determined by the annunciators on the OAP (RT GEN OFF; AC BUS OFF; DC BUS OFF; AC CROSSTIE LOCKOUT). The DC bus came back online when the DC Crosstie was closed. Attempts to reset the right generator did not bring it back online and volts and frequency remained at zero. I requested a descent to FL300 to start the APU. ATC initially approved the request and we began our descent. ATC then amended the altitude to FL310 for traffic. We informed them that we needed FL300 because of a problem on board. They again assigned FL310. I declared an emergency as we were on a single source of electrical power and starting to enter an area of weather without an operable weather radar. I descended to FL300 and started the APU. The RT AC bus came back on line with the APU power and we regained instrumentation and engine instruments; the AC CROSSTIE LOCKOUT annunciator remained on. I elected to divert because of the TS in the destination area. We landed without incident and contacted dispatch/maintenance once parked. Because we were parked remotely; both engines were running when I contacted Maintenance Control. Maintenance directed us to reset the generator and actuate the AC CROSSTIE reset switch. This reset the generator and AC CROSSTIE and brought the generator back on line. I diverted because of an AC GEN failure with an associated AC CROSSTIE LOCKOUT annunciator. This also happened to another flight in the last couple of weeks. I'm not sure how the procedure is actually written on the page of the QRH as I was the PF at the time; but while reading the procedure online at the pubweb site it looks like if the APU starts and picks up the bus that a diversion is not necessary. The problem arises in the way it is presented as the '-END-' that is written after step 8 can (and I believe is) being missed as it is crammed between the last line of the procedure and the 'Continued next page' statement. In the stress of the moment it is easy to miss because of it's placement. If step 8 could be placed on the next page and the '-END-' statement placed more prominently after it; I believe we could avoid unnecessary diversions in the future.
Source: NASA Aviation Safety Reporting System (public domain). Reports are voluntary submissions and are not verified by NASA.
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