Narrative:

On climb out from tri, use of engine anti-ice and wing anti-ice were required. About 10-15 seconds after the wing anti- ice was selected on we got some pressurization bumps. Manual pressurization was then selected and the pressure bumps went away. After about 30 seconds we elected to try the automatic pressurization mode, and the wing anti-ice was selected off also at that time. The pressurization was functioning normal again. Since things appeared normal, wing anti-ice was again selected on as needed. In about 30 seconds the crew smelled something warm and at about the same time one of our passenger came to the cockpit and said the cabin was filling with smoke. We looked back and saw a great deal of smoke. Immediately the PNF requested from ZTL an immediate descent from FL230 and a turn back direct to tri, due to a loss of pressurization. At this same time both pressurization bleed air switches were turned off and the emergency pressurization switch was turned on along with the wing anti-ice switches turned off. Also at the same time we got a tone generator warning indicating the cabin altitude was above 10000 ft and the oxygen masks dropped. ZTL responded immediately with a clearance for us to descend to 11000 ft and cleared direct tri. At the same time the PNF read back this clearance. I (the PF) was removing my headset and sunglasses and donning my oxygen mask and initiating a rapid descent and a 180 degree turn back to tri airport. Obviously there was a great deal going on during this 15 second period of time. The last thing we did was to switch headset to overhead speakers. But we had the clearance we needed. The smoke began to dissipate by this time. Unknown to us, ZTL was requesting information from us during the brief time that we didn't have the overhead speakers on. So we weren't talking back to them. When we turned on the overhead speakers, ZTL cleared us to switch over to tri tower frequency and were acknowledged, called the tower and were issued a clearance to land. We then landed at tri safely. On taxi in the tower asked us to call the tower chief when inside. When we called, the tower said ZTL was upset and wanted to know why we weren't communicating with them for those brief approximately 15 seconds when we switched from headset to overhead speakers. We explained what all was happening. Upon inspection of the aircraft, maintenance discovered the wing anti-ice duct had separated in the pressurized part of the aircraft vessel. This caused the pressure bumps, smoke and in turn, loss of cabin pressure that vented out through the wing anti-ice duct. Callback conversation with reporter revealed the following information: reporter said he was flying gulfstream G2B and was climbing when they experienced this incident. The cause of the loss of pressurization was the failure of a clamp connecting 2 sections of anti-ice ducting which is routed through the pressurized fuselage area. The failed clamp was of the marmon type with a screw fastener to adjust the pressure on the clamp. It was replaced with a riveted type clamp. I wonder how many aircraft are in service with this type of clamp? This would have been more serious if the clamp failed at cruise altitude FL390. The reporter states the FAA has made no contact.

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Original NASA ASRS Text

Title: A GULFSTREAM G2B CPR ACFT EXPERIENCED COMPLETE PRESSURIZATION LOSS AND SMOKE IN CABIN AND COCKPIT. EMER DSCNT AND LNDG MADE AT TRI.

Narrative: ON CLBOUT FROM TRI, USE OF ENG ANTI-ICE AND WING ANTI-ICE WERE REQUIRED. ABOUT 10-15 SECONDS AFTER THE WING ANTI- ICE WAS SELECTED ON WE GOT SOME PRESSURIZATION BUMPS. MANUAL PRESSURIZATION WAS THEN SELECTED AND THE PRESSURE BUMPS WENT AWAY. AFTER ABOUT 30 SECONDS WE ELECTED TO TRY THE AUTO PRESSURIZATION MODE, AND THE WING ANTI-ICE WAS SELECTED OFF ALSO AT THAT TIME. THE PRESSURIZATION WAS FUNCTIONING NORMAL AGAIN. SINCE THINGS APPEARED NORMAL, WING ANTI-ICE WAS AGAIN SELECTED ON AS NEEDED. IN ABOUT 30 SECONDS THE CREW SMELLED SOMETHING WARM AND AT ABOUT THE SAME TIME ONE OF OUR PAX CAME TO THE COCKPIT AND SAID THE CABIN WAS FILLING WITH SMOKE. WE LOOKED BACK AND SAW A GREAT DEAL OF SMOKE. IMMEDIATELY THE PNF REQUESTED FROM ZTL AN IMMEDIATE DSCNT FROM FL230 AND A TURN BACK DIRECT TO TRI, DUE TO A LOSS OF PRESSURIZATION. AT THIS SAME TIME BOTH PRESSURIZATION BLEED AIR SWITCHES WERE TURNED OFF AND THE EMER PRESSURIZATION SWITCH WAS TURNED ON ALONG WITH THE WING ANTI-ICE SWITCHES TURNED OFF. ALSO AT THE SAME TIME WE GOT A TONE GENERATOR WARNING INDICATING THE CABIN ALT WAS ABOVE 10000 FT AND THE OXYGEN MASKS DROPPED. ZTL RESPONDED IMMEDIATELY WITH A CLRNC FOR US TO DSND TO 11000 FT AND CLRED DIRECT TRI. AT THE SAME TIME THE PNF READ BACK THIS CLRNC. I (THE PF) WAS REMOVING MY HEADSET AND SUNGLASSES AND DONNING MY OXYGEN MASK AND INITIATING A RAPID DSCNT AND A 180 DEG TURN BACK TO TRI ARPT. OBVIOUSLY THERE WAS A GREAT DEAL GOING ON DURING THIS 15 SECOND PERIOD OF TIME. THE LAST THING WE DID WAS TO SWITCH HEADSET TO OVERHEAD SPEAKERS. BUT WE HAD THE CLRNC WE NEEDED. THE SMOKE BEGAN TO DISSIPATE BY THIS TIME. UNKNOWN TO US, ZTL WAS REQUESTING INFO FROM US DURING THE BRIEF TIME THAT WE DIDN'T HAVE THE OVERHEAD SPEAKERS ON. SO WE WEREN'T TALKING BACK TO THEM. WHEN WE TURNED ON THE OVERHEAD SPEAKERS, ZTL CLRED US TO SWITCH OVER TO TRI TWR FREQ AND WERE ACKNOWLEDGED, CALLED THE TWR AND WERE ISSUED A CLRNC TO LAND. WE THEN LANDED AT TRI SAFELY. ON TAXI IN THE TWR ASKED US TO CALL THE TWR CHIEF WHEN INSIDE. WHEN WE CALLED, THE TWR SAID ZTL WAS UPSET AND WANTED TO KNOW WHY WE WEREN'T COMMUNICATING WITH THEM FOR THOSE BRIEF APPROX 15 SECONDS WHEN WE SWITCHED FROM HEADSET TO OVERHEAD SPEAKERS. WE EXPLAINED WHAT ALL WAS HAPPENING. UPON INSPECTION OF THE ACFT, MAINT DISCOVERED THE WING ANTI-ICE DUCT HAD SEPARATED IN THE PRESSURIZED PART OF THE ACFT VESSEL. THIS CAUSED THE PRESSURE BUMPS, SMOKE AND IN TURN, LOSS OF CABIN PRESSURE THAT VENTED OUT THROUGH THE WING ANTI-ICE DUCT. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: RPTR SAID HE WAS FLYING GULFSTREAM G2B AND WAS CLBING WHEN THEY EXPERIENCED THIS INCIDENT. THE CAUSE OF THE LOSS OF PRESSURIZATION WAS THE FAILURE OF A CLAMP CONNECTING 2 SECTIONS OF ANTI-ICE DUCTING WHICH IS ROUTED THROUGH THE PRESSURIZED FUSELAGE AREA. THE FAILED CLAMP WAS OF THE MARMON TYPE WITH A SCREW FASTENER TO ADJUST THE PRESSURE ON THE CLAMP. IT WAS REPLACED WITH A RIVETED TYPE CLAMP. I WONDER HOW MANY ACFT ARE IN SVC WITH THIS TYPE OF CLAMP? THIS WOULD HAVE BEEN MORE SERIOUS IF THE CLAMP FAILED AT CRUISE ALT FL390. THE RPTR STATES THE FAA HAS MADE NO CONTACT.

Data retrieved from NASA's ASRS site as of July 2007 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.