B757 first officer reported incorrectly setting the landing altitude in the pressurization panel; re...

Narrative:

During my preflight inspection; while setting the landing altitude in the pressurization panel; I set what I thought was 20 feet for landing. I noticed something looked odd; but couldn't really identify what was out of place. As far as I knew; there are only 4 available digits; so I set 0020.after leveling off and cruising at FL370 for 11 minutes we got a cabin pressure warning. After donning the O2 mask; we started to diagnose the problem. The cabin altitude was steady at 10;000. Shortly after that it finally dawned on me what had previously looked odd about the landing altitude selector. There are not 4 digits; but rather 5 on the selector. The first rotating digit is significantly wider than the following 4 (about 1 inch wide vs an 1/8 of an inch). I had assumed it was stationary; but it's not. When I started the preflight the 10;000 digit was already displayed. So as I rotated the elevation down; I unknowingly stopped at 10;020 feet instead of 0020 feet.needless to say the pressurization panel worked as advertised. We set 0020 and the pressurization returned to normal. As a precaution we requested clearance to descend to FL330 while the pressurization stabilized. After coordination with dispatch and maintenance; we returned to FL370 and continued to destination.my failure to originally trap the error during the preflight cannot be overstated. I take full responsibility for the error and it certainly is a lesson learned. My only questions and concerns for future crews is; why was the controller set above 10;000 feet in the first place? There's no operational reason to do so; since the highest fleet wide landing limitation is 9;500 feet. Is there some maintenance check that requires it? If not; why is there even a 10;000 digit; if it can't be used? Lastly; since there obviously is a 10;000 digit; why is it not consistently labeled as the following digits? The 10;000 digit is either blank or 1. In other words; to set 20 feet you currently set (blank;0;0;2;0). If it were consistent; you would set (0;0;0;2;0).bottom line; lesson learned; won't happen again.

Original NASA ASRS Text

Title: B757 First Officer reported incorrectly setting the landing altitude in the pressurization panel; resulting in a cabin pressure warning which was rectified after the correct landing altitude was entered.

Narrative: During my preflight inspection; while setting the landing altitude in the pressurization panel; I set what I thought was 20 feet for landing. I noticed something looked odd; but couldn't really identify what was out of place. As far as I knew; there are only 4 available digits; so I set 0020.After leveling off and cruising at FL370 for 11 minutes we got a cabin pressure warning. After donning the O2 mask; we started to diagnose the problem. The cabin altitude was steady at 10;000. Shortly after that it finally dawned on me what had previously looked odd about the landing altitude selector. There are not 4 digits; but rather 5 on the selector. The first rotating digit is significantly wider than the following 4 (about 1 inch wide vs an 1/8 of an inch). I had assumed it was stationary; but it's not. When I started the preflight the 10;000 digit was already displayed. So as I rotated the elevation down; I unknowingly stopped at 10;020 feet instead of 0020 feet.Needless to say the pressurization panel worked as advertised. We set 0020 and the pressurization returned to normal. As a precaution we requested clearance to descend to FL330 while the pressurization stabilized. After coordination with Dispatch and Maintenance; we returned to FL370 and continued to destination.My failure to originally trap the error during the preflight cannot be overstated. I take full responsibility for the error and it certainly is a lesson learned. My only questions and concerns for future crews is; why was the controller set above 10;000 feet in the first place? There's no operational reason to do so; since the highest fleet wide landing limitation is 9;500 feet. Is there some maintenance check that requires it? If not; why is there even a 10;000 digit; if it can't be used? Lastly; since there obviously is a 10;000 digit; why is it not consistently labeled as the following digits? The 10;000 digit is either blank or 1. In other words; to set 20 feet you currently set (blank;0;0;2;0). If it were consistent; you would set (0;0;0;2;0).Bottom line; lesson learned; won't happen again.

Data retrieved from NASA's ASRS site 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.

Attributes
ACN	1453095
Time
Date	201705
Local Time Of Day	0601-1200
Place
Locale Reference	ZZZ.ARTCC
State Reference	US
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Make Model Name	B757 Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Flight Phase	Cruise
Flight Plan	IFR
Component
Aircraft Component	Pressurization Control System
Person 1
Function	First Officer Pilot Flying
Qualification	Flight Crew Air Transport Pilot (ATP)
Experience	Flight Crew Type 36
Events
Anomaly	Aircraft Equipment Problem Less Severe Deviation - Procedural Published Material / Policy

B757 first officer reported incorrectly setting the landing altitude in the pressurization panel; resulting in a cabin pressure warning which was rectified after the correct landing altitude was entered.