A C560 captain at FL380 became sleepy because a malfunctioning air cycle machine caused a high fligh...

Attributes
ACN	849266
Time
Date	200908
Local Time Of Day	1201-1800
Place
Locale Reference	ZZZ.Airport
State Reference	US
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Make Model Name	Citation Excel (C560XL)
Operating Under FAR Part	Part 91
Flight Phase	Cruise
Route In Use	Direct
Flight Plan	IFR
Component
Aircraft Component	Air Conditioning and Pressurization Pack
Person 1
Function	Captain Pilot Not Flying
Qualification	Flight Crew Air Transport Pilot (ATP) Flight Crew Flight Instructor
Experience	Flight Crew Last 90 Days 50 Flight Crew Total 4950 Flight Crew Type 1100
Events
Anomaly	Aircraft Equipment Problem Less Severe Flight Deck / Cabin / Aircraft Event Other / Unknown

Narrative:

During cruise flight the cabin became very hot due to a malfunctioning air cycle machine that blew very hot air thru the front defog vents. I ran the cabin fans and inadvertently woke up a sleeping passenger who complained about the noise; so I stopped running the fan. I had the overhead fan on high; but began to feel very hot and woozy. I asked the first officer how he was feeling. He replied ok. I asked him if he was feeling ok to take the controls while I refreshed myself. He said yes; so I transferred controls to the first officer; had some water and adjusted the air as best I could. I believe I inadvertently nodded off for about 5-10 min before the first officer poked me.

Original NASA ASRS Text

Title: A C560 Captain at FL380 became sleepy because a malfunctioning air cycle machine caused a high flight station temperature. He dozed off in flight while the First Officer flew the aircraft.

Narrative: During cruise flight the cabin became very hot due to a malfunctioning air cycle machine that blew very hot air thru the front defog vents. I ran the cabin fans and inadvertently woke up a sleeping passenger who complained about the noise; so I stopped running the fan. I had the overhead fan on high; but began to feel very hot and woozy. I asked the First Officer how he was feeling. He replied OK. I asked him if he was feeling OK to take the controls while I refreshed myself. He said yes; so I transferred controls to the First Officer; had some water and adjusted the air as best I could. I believe I inadvertently nodded off for about 5-10 min before the First Officer poked me.

Data retrieved from NASA's ASRS site as of April 2012 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.

A C560 captain at FL380 became sleepy because a malfunctioning air cycle machine caused a high flight station temperature. He dozed off in flight while the first officer flew the aircraft.