Gulfstream IV / G350 / G450
Flight Crew Air Transport Pilot (ATP)
Physiological - Other
Aircraft Equipment Problem Critical; Deviation / Discrepancy - Procedural Published Material / Policy
Flight Crew Landed As Precaution; Flight Crew Overcame Equipment Problem; Flight Crew Returned To Departure Airport
Aircraft
Departed using Flex power and at 400 feet AGL; flaps were  commanded 'UP.'  A few seconds after the 'Flaps UP' command; a severely painful rapid increase in cabin pressure was felt in the ears by all aboard.  I looked at the cabin pressure 3 in 1 gauge.  It was pegged to 2;000 FPM down.  I commanded:   a.) Select cabin pressure to manual   b.) Select DADC to number 2.   c.) Select Cabin pressure to Auto This initially had no effect; and we selected one engine bleed off; and the cabin rate of descent slowed to 1;000 FPM; then quickly resumed normal operations.  We immediately notified departure:  a.) We had pressurization issue that we would need to resolve.  b.) Needed to stop the climb and vector to an area to work the problem.  c.) Would probably need to return but would require time to burn down fuel to meet MGLW. We leveled at 7;000 feet; and were vectored to the southeast. Notified the Flight Attendant of the issue and stressed it was not a safety of flight but a pressurization issue that we were working on but would in all likely would require returning.  Further; explained that to return we would have to take some time to burn off enough fuel to meet our maximum permissible landing gross weight.  She explained this to the passengers and they were good with this and began to play cards.  We started through the QRH 'LOSS OF AUTOMATIC PRESSURE CONTROL' only through item #3 as the cabin had stabilized.  The Flight Phone was inoperative; therefore the First Officer sent message of our issue to the Company via three different channels. We were vectored to an intersection and instructed to hold east; right turns;  ten (10) mile legs at 7;000 feet MSL.  We determined time to burn down to MGLW and notified ATC.  When satisfactory landing weight was reached we notified ATC.   We were vectored to and completed a visual/ILS.  A normal landing was made; and we taxied to the south ramp.  I had this problem approximately a year ago.  I recalled the checklist up to item 3.  The pain in the ears was intense; and I did not want anyone to endure the pain any longer than necessary and therefore executed the check list from memory to item 3.  Fortunately we got control of the issue and did followup with the QRH through item 3.  I did not consider this a safety of flight/emergency unless we exceed max differential; but the ear pain was severe.  Even though the cabin pressure system seemed to have returned to normal; there was obviously  something wrong with the aircraft; and I saw no reason to continue the flight and take the problem to 41;000 feet and possibly expose us to a worse problem.  A working Flight Phone would have been helpful; but we made every effort through three (3) separate channels to notify the Company; and they immediately started the recovery process.
GIV Captain experiences a cabin over pressure after flap retraction on departure.  Control over the pressurization system is gradually regained; but the Captain elects to return to the departure airport.