PA28 pilot reported losing nearly 1000 ft in a mountain wave encounter in the vicinity of mol VOR.

Attributes
ACN	1405190
Time
Date	201611
Local Time Of Day	0001-0600
Place
Locale Reference	ZDC.ARTCC
State Reference	VA
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Make Model Name	PA-28 Cherokee/Archer/Dakota/Pillan/Warrior
Operating Under FAR Part	Part 91
Flight Phase	Cruise
Flight Plan	IFR
Person 1
Function	Instructor Pilot Flying Single Pilot
Qualification	Flight Crew Flight Instructor Flight Crew Flight Engineer Flight Crew Air Transport Pilot (ATP) Flight Crew Instrument Flight Crew Multiengine
Experience	Flight Crew Last 90 Days 250 Flight Crew Total 25000 Flight Crew Type 800
Events
Anomaly	Deviation - Altitude Excursion From Assigned Altitude Inflight Event / Encounter Weather / Turbulence

Narrative:

We were cruising at 8000 ft and at first we had an increase in altitude with a corresponding increase in airspeed to get back on altitude when we started a 500 ft/min descent. I added full power and raised the nose to compensate to no avail. The 500 ft/min rate continued with our airspeed decaying to 65 knots. The entire event was a smooth ride. No turbulence whatsoever. I called ATC and let them know our situation and got the reply of 'roger'. The loss bottomed out at 7100 feet and we recovered to 8000 ft and normal airspeed. The waves continued but not nearly as severe as this one. Had it continued with the same intensity we could have turned back to the east away from the mountains. I was not informed of any conflicts or loss of separation. Clearly had the descent continued; we would have had to discontinue our southwest course and turned east away from the terrain. I was certainly glad we started at 8000 feet and not any lower. This event makes one appreciate altitude; airspeed and horsepower.

Original NASA ASRS Text

Title: PA28 pilot reported losing nearly 1000 ft in a mountain wave encounter in the vicinity of MOL VOR.

Narrative: We were cruising at 8000 ft and at first we had an increase in altitude with a corresponding increase in airspeed to get back on altitude when we started a 500 ft/min descent. I added full power and raised the nose to compensate to no avail. The 500 ft/min rate continued with our airspeed decaying to 65 knots. The entire event was a smooth ride. No turbulence whatsoever. I called ATC and let them know our situation and got the reply of 'roger'. The loss bottomed out at 7100 feet and we recovered to 8000 ft and normal airspeed. The waves continued but not nearly as severe as this one. Had it continued with the same intensity we could have turned back to the east away from the mountains. I was not informed of any conflicts or loss of separation. Clearly had the descent continued; we would have had to discontinue our SW course and turned east away from the terrain. I was certainly glad we started at 8000 feet and not any lower. This event makes one appreciate altitude; airspeed and horsepower.

Data retrieved from NASA's ASRS site 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.