A C25A captain reported noticing a door seal warning light at FL450. He asked for lower and in the d...

Attributes
ACN	896194
Time
Date	201006
Local Time Of Day	1801-2400
Place
Locale Reference	ZZZ.ARTCC
State Reference	US
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Make Model Name	Citationjet (C525/C526) - CJ I / II / III / IV
Operating Under FAR Part	Part 135
Flight Phase	Cruise
Flight Plan	IFR
Component
Aircraft Component	Exterior Pax/Crew Door
Person 1
Function	Captain Pilot Not Flying
Qualification	Flight Crew Instrument Flight Crew Air Transport Pilot (ATP) Flight Crew Flight Instructor Flight Crew Multiengine
Experience	Flight Crew Last 90 Days 70 Flight Crew Total 4500 Flight Crew Type 400
Events
Anomaly	Aircraft Equipment Problem Critical

Narrative:

Cruising along at FL450; we heard a noise from the cabin. As I looked back; I did not see anything out of the ordinary. However; as I looked forward again; the master caution light illuminated as well as the 'door seal' amber annunciator light. I donned my oxygen mask and told the ARTCC controller that we needed lower. We were given FL410. I pulled out the checklist and we asked for and were eventually given a descent either all the way to or just towards FL310. In the descent; the lights extinguished and the sound stopped. We removed our masks and continued the flight to our destination. ATC did ask us what the problem was; but we did not declare an emergency or ask for priority handling. Our theory was that the door seal had accumulated moisture on the ground where it was hot; humid and we had the air conditioner running. At altitude; this water froze and prevented the door seal from inflating properly. At our destination; we purged the 23 psi air line and lots of water was spit out.

Original NASA ASRS Text

Title: A C25A Captain reported noticing a door seal warning light at FL450. He asked for lower and in the descent the light went out. After landing; a significant amount of water was purged from the seal.

Narrative: Cruising along at FL450; we heard a noise from the cabin. As I looked back; I did not see anything out of the ordinary. However; as I looked forward again; the MASTER CAUTION light illuminated as well as the 'DOOR SEAL' amber annunciator light. I donned my oxygen mask and told the ARTCC Controller that we needed lower. We were given FL410. I pulled out the checklist and we asked for and were eventually given a descent either all the way to or just towards FL310. In the descent; the lights extinguished and the sound stopped. We removed our masks and continued the flight to our destination. ATC did ask us what the problem was; but we did not declare an emergency or ask for priority handling. Our theory was that the door seal had accumulated moisture on the ground where it was hot; humid and we had the air conditioner running. At altitude; this water froze and prevented the door seal from inflating properly. At our destination; we purged the 23 PSI air line and lots of water was spit out.

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 C25A captain reported noticing a door seal warning light at FL450. He asked for lower and in the descent the light went out. After landing; a significant amount of water was purged from the seal.