Hs 125 series 700 captain reported an altitude excursion probably caused by a wake vortex encounter.

Attributes
ACN	1284042
Time
Date	201507
Local Time Of Day	0601-1200
Environment
Flight Conditions	Mixed
Aircraft 1
Make Model Name	HS 125 Series 700
Operating Under FAR Part	Part 91
Flight Phase	Climb
Route In Use	Vectors
Flight Plan	IFR
Aircraft 2
Make Model Name	Any Unknown or Unlisted Aircraft Manufacturer
Person 1
Function	Pilot Flying Captain Instructor
Qualification	Flight Crew Instrument Flight Crew Multiengine Flight Crew Flight Instructor Flight Crew Air Transport Pilot (ATP)
Experience	Flight Crew Last 90 Days 150 Flight Crew Total 17300 Flight Crew Type 2100
Events
Anomaly	Aircraft Equipment Problem Less Severe Deviation - Altitude Excursion From Assigned Altitude Deviation - Procedural Clearance Inflight Event / Encounter Wake Vortex Encounter

Narrative:

We were ferrying an aircraft to africa. On an initial climb to 10;000 feet we were about to level off when the autopilot lurched up and the altitude hold had disengaged. By the time we were able to correct the problem ATC was asking us to stop our climb. We had climbed approximately 3-4 hundred feet rapidly before we were able to disengage the autopilot and return to level flight.we sincerely appreciate the controller's quick response to the matter. Nothing even close to that in africa.after we leveled off and regained our altitude which was over in a few seconds; we did see a jet pass over us about 5;000 feet above us and several miles in front of us. The controller did a great job working with us.

Original NASA ASRS Text

Title: HS 125 Series 700 Captain reported an altitude excursion probably caused by a wake vortex encounter.

Narrative: We were ferrying an aircraft to Africa. On an initial climb to 10;000 feet we were about to level off when the autopilot lurched up and the altitude hold had disengaged. By the time we were able to correct the problem ATC was asking us to stop our climb. We had climbed approximately 3-4 hundred feet rapidly before we were able to disengage the autopilot and return to level flight.We sincerely appreciate the controller's quick response to the matter. Nothing even close to that in Africa.After we leveled off and regained our altitude which was over in a few seconds; we did see a jet pass over us about 5;000 feet above us and several miles in front of us. The controller did a great job working with us.

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.