Is This Loss Of Altitude Possible?
 

I was looking this evening at DL 352 on http://flightaware.com/live/flight/D.../KPHL/tracklog

It shows the flight at 7:56pm at 31000; 7:59pm 30400; 8:00pm 31000

Did he possibly hit turbulence that caused him to lose 600ft in mid-flight and recover one minute later?

No. That was a glitch in the data. Sometimes you'll see a new altitude clearance show up as the actual altitude for a few hits on flightaware before the airplane has climbed or descended to that altitude.

Altitude drop
 

I was flying from HKG to YVR in November and over Japan the plane (330?) dropped over 100 ft. My brother in law screamed (that could be a whole new thread.) My sister in law asked the pilot at the end of the flight what had happened. He said we had flown over an erupting volcano. I cannot see the pilot making this up, but isn't that a very unlikely occurence? It seems like flying over a needle in a haystack. Oops - mixed metaphor.

Don't know about the accuracy of the tracking data, but yes, it's possible for an aircraft to experience a sudden drop, for lots of possible reasons. I experienced it once when a plane I was on was struck by lightning and the electrical systems sputtered for a couple of seconds; the pilot said that we dropped about 100 feet.

I know that there was an incident a couple of years ago near here on a day with bad visibility, where an AA flight came out of a cloud bank to find an F-18 crossing its path. The pilot dove quickly so that they wouldn't collide, and several passengers ended up with minor injuries.

It's probably a glitch in the data. But even at 30,000 ft, a 737 has a climb rate of 1500 feet/minute, so 600/minute in not a big deal. And descending 600 feet in 3 minutes is nothing - that's only 3 feet/second.

An excellent point. At the rates of climb and descent implied by the data, it would take over an hour to reach cruise altitude - and over three hours to get back down. Hardly the sort of thing that leads to flying crockery, deployed oxygen masks, and broken bones.

Agreed. 600 feet in a minute is essentially nothing. Of course, a 600 foot sudden drop would be harsh, but I doubt it this was the case.

In 1985 a China Airlines 747-SP with 274 persons on board descended over 30,000 feet in under 2 1/2 minutes before leveling out at 9600 feet and climbing back to altitude.

I bet you there was many an "evacuation" in that flight. Must have stunk afterwards.