Narrative:

During cruise portion of flight, a mechanic was observed reaching over the shoulder of the flight engineer operating a switch on the flight engineer's panel. It is my opinion that the flight engineer did not want the mechanic to be doing this. In another portion of the flight, the mechanic was in the aft cabin for a lengthy part of the time and smoke and odor started to fill the cockpit. We dawned mask and goggles and ran the checklist. During the checklist communication was established through mask microphone and overhead speakers. Communication was established with the aft cabin. I expected to be talking to one of the cabin attendants instead the mechanic announces that the aft cabin was full of smoke and fumes. Said he had opened up the sliding door between the cargo compartment and the cabin. This of course is not in compliance with our procedures, breaching our smoke barrier. In addition the mechanic initiated these actions on his own initiative without any direction. This corrupted our crew concept and safety. It appears that the mechanic was running the cabin. This was the finest example of reverse CRM I believe that could be put forth. Explanation, normal crew complement is 5 -- 3 flight deck, 2 cabin attendants. This put the captain in position of trying to decide if mechanics are crew or passenger. It is hard to consider them crew if they have had no flight training, oxygen training, egress training, water survival training, flight duty training, security training, crew etiquette training and pro, appearance, conduct in other countries and customs, or conduct on military installations. At this point the only thing that could be assumed is that they are passenger, riding as company employees in the cockpit as jump seat riders. Thus the problem raised its head and created a problem that may well present itself again. One concept could be to purchase a seat in the aft cabin of our equipment or purchase a ticket and have the mechanic meet the aircraft at its destinations. Upon landing, the crew was debriefed without the FAA in attendance. During the debriefing of the cabin attendants with the FAA present, a flight attendant wanted to know some of the maintenance aspects of the problem and continued to ask questions and was given answers to all questions asked with information that was available at the time. With the FAA in attendance, I feel that she received all information requested to her satisfaction. After the FAA was not in attendance, I conveyed for future reference that I thought that she might have waited to get answers when FAA was not present. I believe that her questions were not damaging and answers supplied were not damaging to us as a crew or to our operation or company. It was determined that the recirculating fan was defective and was the cause of the smoke after landing at pjon. It is my opinion that there is a little known limitation that states while aircraft is on the ground that both recirculating fans must be run. Because of this when maintenance is performing maintenance on the ground I suspect that only 1 fan is being run thus causing a high failure rate in these motor units and high remove and replace rates on these fan motors. I've been told that with no back-up documentation on my part that the other fan when running provides cooling airflow thus each fan provides cooling airflow for the other. This might explain the limitation when on the ground both fans need to be operated. This information was passed to me from a deceased senior professional flight engineer that I believe was correct. Supplemental information from acn 509661: I first noticed the problem when we all smelled what seemed to be a hot duct. I went behind the cockpit to feel the overhead for heat, then I looked into the freight compartment, and there was no smell at all. I came back to the cockpit and turned the right recirculating fan off, I then put on my oxygen mask, even though the smell had about gone away. I then read the main cargo smoke or fire checklist, and then we removed our masks and pulled the circuit breakers. The problem was found to be the right recirculating fan that did not open its circuit breakers.

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Original NASA ASRS Text

Title: DC8-62 CREW HAD AN OVERHEATED AIR CONDITIONING RECIRCULATING FAN WHICH CAUSED SMOKE, FUMES IN THE CABIN.

Narrative: DURING CRUISE PORTION OF FLT, A MECH WAS OBSERVED REACHING OVER THE SHOULDER OF THE FE OPERATING A SWITCH ON THE FE'S PANEL. IT IS MY OPINION THAT THE FE DID NOT WANT THE MECH TO BE DOING THIS. IN ANOTHER PORTION OF THE FLT, THE MECH WAS IN THE AFT CABIN FOR A LENGTHY PART OF THE TIME AND SMOKE AND ODOR STARTED TO FILL THE COCKPIT. WE DAWNED MASK AND GOGGLES AND RAN THE CHKLIST. DURING THE CHKLIST COM WAS ESTABLISHED THROUGH MASK MIKE AND OVERHEAD SPEAKERS. COM WAS ESTABLISHED WITH THE AFT CABIN. I EXPECTED TO BE TALKING TO ONE OF THE CABIN ATTENDANTS INSTEAD THE MECH ANNOUNCES THAT THE AFT CABIN WAS FULL OF SMOKE AND FUMES. SAID HE HAD OPENED UP THE SLIDING DOOR BTWN THE CARGO COMPARTMENT AND THE CABIN. THIS OF COURSE IS NOT IN COMPLIANCE WITH OUR PROCS, BREACHING OUR SMOKE BARRIER. IN ADDITION THE MECH INITIATED THESE ACTIONS ON HIS OWN INITIATIVE WITHOUT ANY DIRECTION. THIS CORRUPTED OUR CREW CONCEPT AND SAFETY. IT APPEARS THAT THE MECH WAS RUNNING THE CABIN. THIS WAS THE FINEST EXAMPLE OF REVERSE CRM I BELIEVE THAT COULD BE PUT FORTH. EXPLANATION, NORMAL CREW COMPLEMENT IS 5 -- 3 FLT DECK, 2 CABIN ATTENDANTS. THIS PUT THE CAPT IN POS OF TRYING TO DECIDE IF MECHS ARE CREW OR PAX. IT IS HARD TO CONSIDER THEM CREW IF THEY HAVE HAD NO FLT TRAINING, OXYGEN TRAINING, EGRESS TRAINING, WATER SURVIVAL TRAINING, FLT DUTY TRAINING, SECURITY TRAINING, CREW ETIQUETTE TRAINING AND PRO, APPEARANCE, CONDUCT IN OTHER COUNTRIES AND CUSTOMS, OR CONDUCT ON MIL INSTALLATIONS. AT THIS POINT THE ONLY THING THAT COULD BE ASSUMED IS THAT THEY ARE PAX, RIDING AS COMPANY EMPLOYEES IN THE COCKPIT AS JUMP SEAT RIDERS. THUS THE PROB RAISED ITS HEAD AND CREATED A PROB THAT MAY WELL PRESENT ITSELF AGAIN. ONE CONCEPT COULD BE TO PURCHASE A SEAT IN THE AFT CABIN OF OUR EQUIP OR PURCHASE A TICKET AND HAVE THE MECH MEET THE ACFT AT ITS DESTS. UPON LNDG, THE CREW WAS DEBRIEFED WITHOUT THE FAA IN ATTENDANCE. DURING THE DEBRIEFING OF THE CABIN ATTENDANTS WITH THE FAA PRESENT, A FLT ATTENDANT WANTED TO KNOW SOME OF THE MAINT ASPECTS OF THE PROB AND CONTINUED TO ASK QUESTIONS AND WAS GIVEN ANSWERS TO ALL QUESTIONS ASKED WITH INFO THAT WAS AVAILABLE AT THE TIME. WITH THE FAA IN ATTENDANCE, I FEEL THAT SHE RECEIVED ALL INFO REQUESTED TO HER SATISFACTION. AFTER THE FAA WAS NOT IN ATTENDANCE, I CONVEYED FOR FUTURE REF THAT I THOUGHT THAT SHE MIGHT HAVE WAITED TO GET ANSWERS WHEN FAA WAS NOT PRESENT. I BELIEVE THAT HER QUESTIONS WERE NOT DAMAGING AND ANSWERS SUPPLIED WERE NOT DAMAGING TO US AS A CREW OR TO OUR OP OR COMPANY. IT WAS DETERMINED THAT THE RECIRCULATING FAN WAS DEFECTIVE AND WAS THE CAUSE OF THE SMOKE AFTER LNDG AT PJON. IT IS MY OPINION THAT THERE IS A LITTLE KNOWN LIMITATION THAT STATES WHILE ACFT IS ON THE GND THAT BOTH RECIRCULATING FANS MUST BE RUN. BECAUSE OF THIS WHEN MAINT IS PERFORMING MAINT ON THE GND I SUSPECT THAT ONLY 1 FAN IS BEING RUN THUS CAUSING A HIGH FAILURE RATE IN THESE MOTOR UNITS AND HIGH REMOVE AND REPLACE RATES ON THESE FAN MOTORS. I'VE BEEN TOLD THAT WITH NO BACK-UP DOCUMENTATION ON MY PART THAT THE OTHER FAN WHEN RUNNING PROVIDES COOLING AIRFLOW THUS EACH FAN PROVIDES COOLING AIRFLOW FOR THE OTHER. THIS MIGHT EXPLAIN THE LIMITATION WHEN ON THE GND BOTH FANS NEED TO BE OPERATED. THIS INFO WAS PASSED TO ME FROM A DECEASED SENIOR PROFESSIONAL FE THAT I BELIEVE WAS CORRECT. SUPPLEMENTAL INFO FROM ACN 509661: I FIRST NOTICED THE PROB WHEN WE ALL SMELLED WHAT SEEMED TO BE A HOT DUCT. I WENT BEHIND THE COCKPIT TO FEEL THE OVERHEAD FOR HEAT, THEN I LOOKED INTO THE FREIGHT COMPARTMENT, AND THERE WAS NO SMELL AT ALL. I CAME BACK TO THE COCKPIT AND TURNED THE R RECIRCULATING FAN OFF, I THEN PUT ON MY OXYGEN MASK, EVEN THOUGH THE SMELL HAD ABOUT GONE AWAY. I THEN READ THE MAIN CARGO SMOKE OR FIRE CHKLIST, AND THEN WE REMOVED OUR MASKS AND PULLED THE CIRCUIT BREAKERS. THE PROB WAS FOUND TO BE THE R RECIRCULATING FAN THAT DID NOT OPEN ITS CIRCUIT BREAKERS.

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.