Lj-55 crew had no pressurization after forgetting to turn the aircraft pneumatic system on.

Attributes
ACN	511279
Time
Date	200105
Day	Tue
Local Time Of Day	0601 To 1200
Place
Locale Reference	atc facility : zkc.artcc
State Reference	KS
Altitude	msl single value : 20000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zkc.artcc
Operator	common carrier : air taxi
Make Model Name	Learjet 55
Operating Under FAR Part	Part 91
Flight Phase	climbout : intermediate altitude
Flight Plan	IFR
Person 1
Affiliation	company : air taxi
Function	flight crew : first officer
Qualification	pilot : atp pilot : multi engine
Experience	flight time last 90 days : 60 flight time total : 3500 flight time type : 950
ASRS Report	511279
Person 2
Affiliation	company : air taxi
Function	flight crew : captain oversight : pic
Events
Anomaly	aircraft equipment problem : critical non adherence : company policies non adherence : published procedure other anomaly other
Independent Detector	aircraft equipment other aircraft equipment : cabin altimeter other flight crewa other flight crewb
Resolutory Action	controller : issued new clearance controller : provided flight assist flight crew : declared emergency none taken : detected after the fact other
Consequence	other
Supplementary
Problem Areas	Flight Crew Human Performance Aircraft
Primary Problem	Flight Crew Human Performance

Narrative:

Picked-up plane from maintenance facility at ZZZ (electrical maintenance). Checklist was interrupted several times in preflight. (Missed bleed air switches). Takeoff from ZZZ was at approximately XC40 Z. 'After takeoff checklist' was delayed while we worked with a VOR 1 malfunction. We were cleared to FL230, I heard noise in back of cabin. (Thought something fell down) at about 15000 ft (note: 'no' altitude alerter horn, even though it tested fine in preflight.) pilot flying captain X, noticed cabin altitude climbing rapidly through 20000 and ears started to pop. Did memory items. Squawked '7700' started descent, contacted ATC, probably went through 18000 ft before able to contact ATC. ATC then cleared us to 10000 ft! Found bleed air switches off. Fixed problem. Resumed trip to 'pie' (st. Petersburg, fl) P.south. 'Cabin altitude' light did come on, the noise in the back of cabin was oxygen mask falling. But 'no' altitude alerter 'horn'. Callback conversation with reporter revealed the following information: the cabin altitude warning horn checked normal before takeoff. Another test was accomplished after landing and it again tested normally. It did not provide any warning when the cabin altitude was exceeded however. The reporter does not know why it tests normal, but fails to provide an actual warning.

Original NASA ASRS Text

Title: LJ-55 CREW HAD NO PRESSURIZATION AFTER FORGETTING TO TURN THE ACFT PNEUMATIC SYS ON.

Narrative: PICKED-UP PLANE FROM MAINT FAC AT ZZZ (ELECTRICAL MAINT). CHKLIST WAS INTERRUPTED SEVERAL TIMES IN PREFLT. (MISSED BLEED AIR SWITCHES). TKOF FROM ZZZ WAS AT APPROX XC40 Z. 'AFTER TKOF CHKLIST' WAS DELAYED WHILE WE WORKED WITH A VOR 1 MALFUNCTION. WE WERE CLRED TO FL230, I HEARD NOISE IN BACK OF CABIN. (THOUGHT SOMETHING FELL DOWN) AT ABOUT 15000 FT (NOTE: 'NO' ALTITUDE ALERTER HORN, EVEN THOUGH IT TESTED FINE IN PREFLT.) PLT FLYING CAPTAIN X, NOTICED CABIN ALTITUDE CLBING RAPIDLY THROUGH 20000 AND EARS STARTED TO POP. DID MEMORY ITEMS. SQUAWKED '7700' STARTED DSCNT, CONTACTED ATC, PROBABLY WENT THROUGH 18000 FT BEFORE ABLE TO CONTACT ATC. ATC THEN CLRED US TO 10000 FT! FOUND BLEED AIR SWITCHES OFF. FIXED PROB. RESUMED TRIP TO 'PIE' (ST. PETERSBURG, FL) P.S. 'CABIN ALT' LIGHT DID COME ON, THE NOISE IN THE BACK OF CABIN WAS OXYGEN MASK FALLING. BUT 'NO' ALTITUDE ALERTER 'HORN'. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE CABIN ALTITUDE WARNING HORN CHKED NORMAL BEFORE TKOF. ANOTHER TEST WAS ACCOMPLISHED AFTER LNDG AND IT AGAIN TESTED NORMALLY. IT DID NOT PROVIDE ANY WARNING WHEN THE CABIN ALT WAS EXCEEDED HOWEVER. THE RPTR DOES NOT KNOW WHY IT TESTS NORMAL, BUT FAILS TO PROVIDE AN ACTUAL WARNING.

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.