FAA inspector found cooling fan circuit breaker pulled during cockpit inspection.

Attributes
ACN	86577
Time
Date	198804
Day	Fri
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : stl
State Reference	MO
Altitude	agl bound lower : 0 agl bound upper : 0
Environment
Light	Daylight
Aircraft 1
Operator	common carrier : air carrier
Make Model Name	Medium Large Transport, Low Wing, 2 Turbojet Eng
Navigation In Use	Other
Flight Phase	ground : preflight
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : commercial pilot : instrument pilot : flight engineer
Experience	flight time last 90 days : 200 flight time total : 14000 flight time type : 1400
ASRS Report	86577
Person 2
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Events
Anomaly	aircraft equipment problem : less severe non adherence : published procedure non adherence : far
Independent Detector	other other : unspecified
Resolutory Action	other
Consequence	faa : investigated
Supplementary
Primary Problem	Aircraft
Air Traffic Incident	Pilot Deviation

Narrative:

During ground operations of this flight a circuit breaker for a cooling fan was pulled. This fan was designed for an medium large transport with the glass cockpit. Our medium large transport has a standard cockpit. With the fan running it is almost impossible to hear in the cockpit. The fan does not run during flight. The airline is modifying these aircraft to remove this unnecessary nuisance to normal operation. Callback conversation with reporter revealed the following: this fan causes a level of noise that apparently causes flight crews to snap at one another as a result of noise induced stress. Reporter has experimented with fan on and off and found he can control a level of stress in the cockpit. Also, the fan is controled by the nose gear squat switch and turns off the instant the nose gear leaves the ground. Reporter says this is a poor time because as the fan stops, the flight crew wonders what has just quit working, even suspecting the loss of an engine. He also said that at least 4 of the 6 aircraft of this type his airline owns have been converted and the fans have been disabled. It should no longer be a problem on his airline. He thinks this noise causes a subliminal but profound effect on human factors and flight crew performance. FAA aci discovered circuit breaker pulled on cockpit inspection.

Original NASA ASRS Text

Title: FAA INSPECTOR FOUND COOLING FAN CIRCUIT BREAKER PULLED DURING COCKPIT INSPECTION.

Narrative: DURING GND OPS OF THIS FLT A CB FOR A COOLING FAN WAS PULLED. THIS FAN WAS DESIGNED FOR AN MLG WITH THE GLASS COCKPIT. OUR MLG HAS A STANDARD COCKPIT. WITH THE FAN RUNNING IT IS ALMOST IMPOSSIBLE TO HEAR IN THE COCKPIT. THE FAN DOES NOT RUN DURING FLT. THE AIRLINE IS MODIFYING THESE ACFT TO REMOVE THIS UNNECESSARY NUISANCE TO NORMAL OPERATION. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING: THIS FAN CAUSES A LEVEL OF NOISE THAT APPARENTLY CAUSES FLT CREWS TO SNAP AT ONE ANOTHER AS A RESULT OF NOISE INDUCED STRESS. RPTR HAS EXPERIMENTED WITH FAN ON AND OFF AND FOUND HE CAN CTL A LEVEL OF STRESS IN THE COCKPIT. ALSO, THE FAN IS CTLED BY THE NOSE GEAR SQUAT SWITCH AND TURNS OFF THE INSTANT THE NOSE GEAR LEAVES THE GND. RPTR SAYS THIS IS A POOR TIME BECAUSE AS THE FAN STOPS, THE FLT CREW WONDERS WHAT HAS JUST QUIT WORKING, EVEN SUSPECTING THE LOSS OF AN ENG. HE ALSO SAID THAT AT LEAST 4 OF THE 6 ACFT OF THIS TYPE HIS AIRLINE OWNS HAVE BEEN CONVERTED AND THE FANS HAVE BEEN DISABLED. IT SHOULD NO LONGER BE A PROB ON HIS AIRLINE. HE THINKS THIS NOISE CAUSES A SUBLIMINAL BUT PROFOUND EFFECT ON HUMAN FACTORS AND FLT CREW PERFORMANCE. FAA ACI DISCOVERED CB PULLED ON COCKPIT INSPECTION.

Data retrieved from NASA's ASRS site as of August 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.