37000 Feet | Browse and search NASA's Aviation Safety Reporting System |
|
Attributes | |
ACN | 1268172 |
Time | |
Date | 201506 |
Local Time Of Day | 1201-1800 |
Place | |
Locale Reference | ZZZ.Airport |
State Reference | US |
Environment | |
Light | Daylight |
Aircraft 1 | |
Make Model Name | Dash 8-200 |
Operating Under FAR Part | Part 121 |
Flight Phase | Cruise |
Flight Plan | IFR |
Component | |
Aircraft Component | Indicating and Warning - Air Conditioning and Press. |
Person 1 | |
Function | Captain Pilot Not Flying |
Qualification | Flight Crew Air Transport Pilot (ATP) |
Person 2 | |
Function | Pilot Flying First Officer |
Qualification | Flight Crew Air Transport Pilot (ATP) |
Events | |
Anomaly | Aircraft Equipment Problem Less Severe Deviation - Procedural Published Material / Policy Inflight Event / Encounter Fuel Issue Inflight Event / Encounter Weather / Turbulence |
Narrative:
The first indication of a problem on this flight occurred while leveling off at 16;000 feet. When prompted to check the pressurization system on the cruise checklist I noticed that the cabin differential and cabin altitude were acting abnormal. The cabin altitude was indicating erratic indications between 3;000 and 4000 feet. The differential indicator seemed to be trying to indicate a cabin differential around 5; however was also indicating erratically in excess of this number up to around 6. Obviously this alarmed me at first because this exceeds the maximum differential number so my first thought was we need to begin a descent to decrease the cabin differential and run the checklist.I had a little trouble finding an appropriate checklist and settled on the cabin pressurization fail checklist only to find it not very fitting for our scenario. I knew the cabin was not fluctuating as indicated because surely I would have been able to feel sharp spikes in cabin altitude descending and climbing. Also; it was important to note that the cabin altitude rate of climb indicator was fixed at a 1;000 feet per minute climb. I asked center for a precautionary descent to 10;000 feet which was immediately approved. We descended in an expeditious manner. When level at 10;000 feet the indicators all seemed normal; however the cabin rate did remain fixed at 1;000 FPM climb for the remainder of the flight. I called the flight attendant and asked if everything was ok in back. She said she noticed nothing abnormal. I told her we were flying lower than normal as a precaution but still expect us to continue to ZZZ1 as planned.my next concern was fuel. We did not have a lot of extra fuel; and it takes a very long time to reach our cruising altitude on this flight because new york center always keeps us low longer for jet traffic to climb above which uses more fuel. I had burn numbers for 10;000 feet; but still called dispatch to ask if we wanted to continue to ZZZ1 or turn back to ZZZ; we were about half way at the time; also I wanted some feedback from maintenance control. They agreed 10;000 feet was fine and continue to ZZZ1. I did lose contact with dispatch toward the end; but I asked ATC to call our company and advise them we believed our fuel was sufficient to continue to ZZZ1 at this lower altitude. I did initially declare minimum fuel; however I was immediately given direct to the field; which cut off a lot of time; so they asked if the declaration was still needed; and I said it was not. We flew a bit slower than normal to conserve fuel. Lastly; it is important to note we did not depart with the 4;200 lbs of fuel as indicated on the release; but instead the dispatcher and I agreed on 4;000 lbs for weight and balance issues; and this left us with about 250 lbs of extra fuel.we continued to ZZZ1 only to figure out that our weather radar was not working properly. I noticed an area of precipitation and turned it on and it depicted nothing but random yellow streaking lines. I asked ATC if they were showing any precipitation. They said they showed it as an area of moderate precipitation. I asked for a deviation and avoided it visually. I also asked for assistance as we got closer to ZZZ1 in case there were any other areas of precipitation. We arrived at ZZZ1 and upon touchdown we immediately got a caution light. I identified the #1 / #2 engine manual caution lights and cancelled it. We cleared the runway and ran the checklist. We feathered the propellers as directed by the checklist. The checklist advised with dual engine manual cautions to be towed to the gate. I advised air traffic control it would be some time and to try and assemble a tow team.maintenance control advised we could allow the first officer to go outside on the taxiway and reset a circuit breaker in the nose. I did not want to do that. We eventually had contract maintenance meet us on the taxiway and reset the breaker. It fixed the problem and cleared the cautionlight. Because of the proximity to the #1 engine I shut it down when the maintenance person was resetting this circuit breaker. I was unable to restart the #1 engine. The #2 engine was out of feather and functioning normally. I asked to be towed because of the abnormal situation taxiing on one engine. I was advised by airport operations that [air carrier] had just switched to outsourced vendors in ZZZ1 and he was not confident in their abilities to tow us that distance across a runway. I decided it was much safer to taxi single engine. I did that without incident. The flight attendant and passengers were very up to date with this situation as it unfolded. I entered discrepancies into the aircraft logbook once we reached the gate and contacted the necessary parties.
Original NASA ASRS Text
Title: A DHC-8 flight crew experienced aircraft pressurization indications that they thought to be erroneous. They ran the checklists; descended; and continued to their destination. On landing their ECUs failed requiring Maintenance to reset the ECU circuit breakers. They then taxied to the gate.
Narrative: The first indication of a problem on this flight occurred while leveling off at 16;000 feet. When prompted to check the pressurization system on the cruise checklist I noticed that the cabin differential and cabin altitude were acting abnormal. The cabin altitude was indicating erratic indications between 3;000 and 4000 feet. The differential indicator seemed to be trying to indicate a cabin differential around 5; however was also indicating erratically in excess of this number up to around 6. Obviously this alarmed me at first because this exceeds the maximum differential number so my first thought was we need to begin a descent to decrease the cabin differential and run the checklist.I had a little trouble finding an appropriate checklist and settled on the cabin pressurization fail checklist only to find it not very fitting for our scenario. I knew the cabin was not fluctuating as indicated because surely I would have been able to feel sharp spikes in cabin altitude descending and climbing. Also; it was important to note that the cabin altitude rate of climb indicator was fixed at a 1;000 feet per minute climb. I asked Center for a precautionary descent to 10;000 feet which was immediately approved. We descended in an expeditious manner. When level at 10;000 feet the indicators all seemed normal; however the cabin rate did remain fixed at 1;000 FPM climb for the remainder of the flight. I called the Flight Attendant and asked if everything was ok in back. She said she noticed nothing abnormal. I told her we were flying lower than normal as a precaution but still expect us to continue to ZZZ1 as planned.My next concern was fuel. We did not have a lot of extra fuel; and it takes a very long time to reach our cruising altitude on this flight because New York Center always keeps us low longer for jet traffic to climb above which uses more fuel. I had burn numbers for 10;000 feet; but still called Dispatch to ask if we wanted to continue to ZZZ1 or turn back to ZZZ; we were about half way at the time; also I wanted some feedback from Maintenance Control. They agreed 10;000 feet was fine and continue to ZZZ1. I did lose contact with Dispatch toward the end; but I asked ATC to call our company and advise them we believed our fuel was sufficient to continue to ZZZ1 at this lower altitude. I did initially declare minimum fuel; however I was immediately given direct to the field; which cut off a lot of time; so they asked if the declaration was still needed; and I said it was not. We flew a bit slower than normal to conserve fuel. Lastly; it is important to note we did not depart with the 4;200 lbs of fuel as indicated on the release; but instead the Dispatcher and I agreed on 4;000 lbs for weight and balance issues; and this left us with about 250 lbs of extra fuel.We continued to ZZZ1 only to figure out that our weather radar was not working properly. I noticed an area of precipitation and turned it on and it depicted nothing but random yellow streaking lines. I asked ATC if they were showing any precipitation. They said they showed it as an area of moderate precipitation. I asked for a deviation and avoided it visually. I also asked for assistance as we got closer to ZZZ1 in case there were any other areas of precipitation. We arrived at ZZZ1 and upon touchdown we immediately got a caution light. I identified the #1 / #2 Engine Manual caution lights and cancelled it. We cleared the runway and ran the checklist. We feathered the propellers as directed by the checklist. The checklist advised with dual engine manual cautions to be towed to the gate. I advised air traffic control it would be some time and to try and assemble a tow team.Maintenance Control advised we could allow the first officer to go outside on the taxiway and reset a circuit breaker in the nose. I did not want to do that. We eventually had Contract Maintenance meet us on the taxiway and reset the breaker. It fixed the problem and cleared the cautionlight. Because of the proximity to the #1 engine I shut it down when the maintenance person was resetting this circuit breaker. I was unable to restart the #1 engine. The #2 engine was out of feather and functioning normally. I asked to be towed because of the abnormal situation taxiing on one engine. I was advised by airport operations that [air carrier] had just switched to outsourced vendors in ZZZ1 and he was not confident in their abilities to tow us that distance across a runway. I decided it was much safer to taxi single engine. I did that without incident. The Flight Attendant and passengers were very up to date with this situation as it unfolded. I entered discrepancies into the aircraft logbook once we reached the gate and contacted the necessary parties.
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.