B737 Undifferentiated or Other Model
Flight Crew Multiengine; Flight Crew Instrument; Flight Crew Air Transport Pilot (ATP)
Flight Crew Last 90 Days 167; Flight Crew Total 22000; Flight Crew Type 10700
Confusion; Situational Awareness
Aircraft Equipment Problem Less Severe; Deviation / Discrepancy - Procedural Security; Deviation / Discrepancy - Procedural Published Material / Policy; Flight Deck / Cabin / Aircraft Event Other / Unknown
General None Reported / Taken
Procedure; Company Policy; Aircraft
At rotation the flight deck door fully opened. The door was immediately shut by one of the forward flight attendants. Upon inspection; the Boeing door flight deck access switch was found disarmed and the switch in the off position. We immediately repositioned and rearmed the switch. The flight continued without incident. Several errors where made that led to this situation. The initial preflight procedure was either not done properly or the switch was disarmed afterwards. And; the before push check of the flight deck door was not done properly.I cannot say that there was anything specific that led to these errors. The flight was late; a maintenance swap; and a last minute crew change. We were hurrying but I did not feel rushed. We were dealing with iPad and flight planning difficulties related to the changes that kept us more occupied than normal.Two company norms did not help our situation: First; I have found that several flight attendants on the Boeing door; disarmed the flight deck access switch and put it in the off position. This is done to keep the door from closing and locking while at the gate. I assume this is common practice on another equipment because it is so widespread. I have never liked the practice disabling safety equipment! If a lock prevention method is to be used; I prefer to use the galley curtain folded into the jumpseat gap. This is just as effective at keeping the door from locking and it is blatantly obvious when it is used. On a side note; care should be used with the curtain also. I have found instances where the curtain was folded into the space above the gap and dislodges the jumpseat oxygen mask. Second; many pilots (including myself) use the flight deck door lock panel area on the pedestal to store all of the printed materials. I will use more care to ensure this material is folded to fit into the blank space only.
[Report narrative contained no additional information.]
B737 flight crew reported the flight deck door came open upon rotation due to a switch being in the wrong position.