All three MD80 gyros failed in cruise flight resulting in the loss of autothrottle; flight directors...

Narrative:

I was pm. First indication of problem came at around 10000' MSL when the autothrottle disconnected along with my (captain's) FD steering bars biasing out of view and all four FMA windows on my side blanking out. Note- there was no FD fail or any other warning indication displayed and all circuit breakers were in. I ran the left FD fail checklist from the QRH as this was the closest to the problem at hand. When I selected FD cmd both on 2; I got back the steering bars and fmas. Completing the checklist; we eventually leveled off. I was a bit concerned that no warning flags illuminated; so I contacted maintenance through dispatch and discussed the problem. They agreed with my assessment of the situation and intention to continue to the filed destination as there was no 'land at nearest airport' in the procedure I ran. About 45 minutes later; things got weird. This time; both captain's and first officer's steering bars disappeared; autopilot and autothrottle disengaged; both sets of fmas went blank and still no warning or failure indications anywhere in the cockpit. This is where I declared an emergency and diverted to a nearby airport. I advised the flight attendants of the situation; informed the passengers via PA and sent a diversion report on the ACARS. The first officer did an outstanding job in hand flying out of 35000' and on toward our divert airport. At about 10000' I assumed the controls for the landing; not really sure what to expect; when all the failed equipment came back to life. We then landed rwy 12R. Everything worked normally all the way to the gate. When maintenance ran a test; they told me three of the vertical gyros had failed for a time; which would explain the loss of so many items. Still; why no warning that this had happened? This incident was definitely a first for me in almost twenty years of flying the md-80. Fortunately; my selection of this particular airport enabled us to get a replacement aircraft and were able to safely get our passengers to their destination about an hour later than scheduled.

Original NASA ASRS Text

Title: All three MD80 gyros failed in cruise flight resulting in the loss of autothrottle; Flight Directors and other items. An emergency was declared and the flight diverted to a nearby airport but the failed equipment restored before landing.

Narrative: I was PM. First indication of problem came at around 10000' MSL when the Autothrottle disconnected along with my (Captain's) FD steering bars biasing out of view and all four FMA windows on my side blanking out. Note- there was NO FD FAIL or any other warning indication displayed and all circuit breakers were in. I ran the Left FD FAIL checklist from the QRH as this was the closest to the problem at hand. When I selected FD CMD BOTH ON 2; I got back the steering bars and FMAs. Completing the checklist; we eventually leveled off. I was a bit concerned that no warning flags illuminated; so I contacted maintenance through Dispatch and discussed the problem. They agreed with my assessment of the situation and intention to continue to the filed destination as there was no 'land at nearest airport' in the procedure I ran. About 45 minutes later; things got weird. This time; BOTH Captain's and First Officer's steering bars disappeared; autopilot and autothrottle disengaged; both sets of FMAs went blank and still NO warning or failure indications anywhere in the cockpit. This is where I declared an emergency and diverted to a nearby airport. I advised the flight attendants of the situation; informed the passengers via PA and sent a diversion report on the ACARS. The First Officer did an outstanding job in hand flying out of 35000' and on toward our divert airport. At about 10000' I assumed the controls for the landing; not really sure what to expect; when all the failed equipment came back to life. We then landed Rwy 12R. Everything worked normally all the way to the gate. When Maintenance ran a test; they told me three of the vertical gyros had failed for a time; which would explain the loss of so many items. Still; why no warning that this had happened? This incident was definitely a first for me in almost twenty years of flying the MD-80. Fortunately; my selection of this particular airport enabled us to get a replacement aircraft and were able to safely get our passengers to their destination about an hour later than scheduled.

Data retrieved from NASA's ASRS site as of April 2012 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.

Attributes
ACN	957980
Time
Date	201107
Local Time Of Day	0001-0600
Place
Locale Reference	ZZZ.ARTCC
State Reference	US
Environment
Flight Conditions	VMC
Light	Night
Aircraft 1
Make Model Name	MD-80 Series (DC-9-80) Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Flight Phase	Cruise
Flight Plan	IFR
Component
Aircraft Component	INS / IRS / IRU
Person 1
Function	Pilot Not Flying Captain
Qualification	Flight Crew Air Transport Pilot (ATP)
Events
Anomaly	Aircraft Equipment Problem Critical

All three MD80 gyros failed in cruise flight resulting in the loss of autothrottle; flight directors and other items. An emergency was declared and the flight diverted to a nearby airport but the failed equipment restored before landing.