Flight crew of DH8C fail to set 29.92 passing FL180 and level at FL205. ATC alerts before conflict.

Attributes
ACN	639890
Time
Date	200412
Day	Mon
Local Time Of Day	1801 To 2400
Place
Locale Reference	airport : sea.airport
State Reference	WA
Altitude	msl single value : 20000
Environment
Flight Conditions	Mixed
Weather Elements	Turbulence
Light	Night
Aircraft 1
Controlling Facilities	artcc : zse.artcc
Operator	common carrier : air carrier
Make Model Name	Dash 8-200
Operating Under FAR Part	Part 121
Flight Phase	cruise : level cruise : enroute altitude change
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 80 flight time total : 4800 flight time type : 3600
ASRS Report	639890
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Events
Anomaly	altitude deviation : overshoot conflict : airborne less severe non adherence : clearance non adherence : far
Independent Detector	aircraft equipment other aircraft equipment : mode c readout other controllera
Resolutory Action	controller : issued alert flight crew : returned to assigned altitude
Supplementary
Problem Areas	Flight Crew Human Performance
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

We leveled off at 16000 ft on an altimeter setting of 29.43. Due to darkness, we couldn't tell at first that we were leveling right at the tops of a layer. We began getting continuous light chop, so we requested FL200. The altitude was granted, and my first officer began the climb. Using the autoplt he climbed around 2000 FPM, which is greater than usual, especially at that altitude. This high rate of climb caused the forward outflow valve to open. This makes a unique sound, since it is on the forward bulkhead, causing us to look up at the pressurization panel overhead. We then began discussing why it opened, and determined it was appropriate since the cabin was at maximum differential. While talking, we missed our standard '1000 ft to go' call, and our '29.92' call. We leveled at FL200 and set cruise power. A few mins later, ATC called and said 'say altitude.' I looked at the altimeter, then at the altimeter setting and saw it was still at 29.43. I quickly set it to 29.92 and seeing we were 500 ft high, stated 'descending back down to FL200.' ATC then stated, 'roger, maintain FL200 for traffic.' event over. No traffic conflicts.

Original NASA ASRS Text

Title: FLT CREW OF DH8C FAIL TO SET 29.92 PASSING FL180 AND LEVEL AT FL205. ATC ALERTS BEFORE CONFLICT.

Narrative: WE LEVELED OFF AT 16000 FT ON AN ALTIMETER SETTING OF 29.43. DUE TO DARKNESS, WE COULDN'T TELL AT FIRST THAT WE WERE LEVELING RIGHT AT THE TOPS OF A LAYER. WE BEGAN GETTING CONTINUOUS LIGHT CHOP, SO WE REQUESTED FL200. THE ALT WAS GRANTED, AND MY FO BEGAN THE CLB. USING THE AUTOPLT HE CLBED AROUND 2000 FPM, WHICH IS GREATER THAN USUAL, ESPECIALLY AT THAT ALT. THIS HIGH RATE OF CLB CAUSED THE FORWARD OUTFLOW VALVE TO OPEN. THIS MAKES A UNIQUE SOUND, SINCE IT IS ON THE FORWARD BULKHEAD, CAUSING US TO LOOK UP AT THE PRESSURIZATION PANEL OVERHEAD. WE THEN BEGAN DISCUSSING WHY IT OPENED, AND DETERMINED IT WAS APPROPRIATE SINCE THE CABIN WAS AT MAX DIFFERENTIAL. WHILE TALKING, WE MISSED OUR STANDARD '1000 FT TO GO' CALL, AND OUR '29.92' CALL. WE LEVELED AT FL200 AND SET CRUISE PWR. A FEW MINS LATER, ATC CALLED AND SAID 'SAY ALT.' I LOOKED AT THE ALTIMETER, THEN AT THE ALTIMETER SETTING AND SAW IT WAS STILL AT 29.43. I QUICKLY SET IT TO 29.92 AND SEEING WE WERE 500 FT HIGH, STATED 'DSNDING BACK DOWN TO FL200.' ATC THEN STATED, 'ROGER, MAINTAIN FL200 FOR TFC.' EVENT OVER. NO TFC CONFLICTS.

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.