37000 Feet | Browse and search NASA's Aviation Safety Reporting System |
|
Attributes | |
ACN | 1125514 |
Time | |
Date | 201310 |
Local Time Of Day | 0601-1200 |
Place | |
Locale Reference | LAS.Airport |
State Reference | NV |
Environment | |
Flight Conditions | VMC |
Light | Daylight |
Aircraft 1 | |
Make Model Name | B737-700 |
Operating Under FAR Part | Part 121 |
Flight Phase | Takeoff |
Flight Plan | IFR |
Person 1 | |
Function | Captain Pilot Not Flying |
Events | |
Anomaly | Inflight Event / Encounter Loss Of Aircraft Control Inflight Event / Encounter Wake Vortex Encounter |
Narrative:
[I] cleared to taxi to [runway] 1R for departure. Previous ATIS showed seven knots of tailwind. We discussed this with each other and queried tower. They advised new ATIS and calm winds. We commented among ourselves that probably at 100 ft AGL the tailwind would still be there. Typical heavy departure procedures that you regularly get in phx and las ATC asks you to verify previous departure in sight and clears you for takeoff as the previous departure is lifting off. Previous departure was a B737-700 with a west departure. We had a normal takeoff roll and rotation. As I retracted the gear; the airplane started a violent roll to the right. The first officer applied full opposite aileron. I pushed the yoke forward and simultaneously said 'push the nose down'. The airplane started to reduce bank and climb normally. By this time we were over the parallel taxiway east of [runway] 1R correcting heading and noticing that LNAV had failed and we couldn't restore it. The first officer flew raw data on the map until we were able to restore LNAV shortly after. We also noticed a big white flashing box around the engine instruments' indications showing oil quantity low and depleting. It wound up being a classic case of oil gulping for the number 1 engine; but it was eye opening with all the other occurrences. The engine oil indication started [to] replenish 30 to 40 seconds later. We continued to climb and landed uneventfully. We had two inquiries regarding the departure; one from our a flight attendant who noticed the unusual attitude; and a couple from passengers in the back of the aircraft; one of whom was a private pilot and asked if we encountered wake turbulence. The first officer was at the controls the entire time and did an excellent job of recovering from the wake turbulence. Preventative measures: the obvious is that we could have delayed takeoff and left more spacing. ATC could do the same. The reality is that they are trying to move metal as quickly as we are and both of us are mission-oriented. The preceding airplane was not a heavy so they and we complied with all procedures. It is apparent to me that the B737-700 wing produces a more significant wake vortices than other models. I don't know if it's because of wing shape or the heavier gross weights the aircraft is capable of taking off at. Some consideration should be given to researching the actual wake the airplane produces and coordinating departure spacing with ATC accordingly.
Original NASA ASRS Text
Title: B737-700 Captain reported a 'violent' wake vortex encounter after takeoff at LAS in trail of another B737-700. He commented that the -700 seemed to have more significant wake than other aircraft and perhaps in-trail considerations should be reviewed when the -700 is involved.
Narrative: [I] cleared to taxi to [Runway] 1R for departure. Previous ATIS showed seven knots of tailwind. We discussed this with each other and queried Tower. They advised new ATIS and calm winds. We commented among ourselves that probably at 100 FT AGL the tailwind would still be there. Typical heavy departure procedures that you regularly get in PHX and LAS ATC asks you to verify previous departure in sight and clears you for takeoff as the previous departure is lifting off. Previous departure was a B737-700 with a west departure. We had a normal takeoff roll and rotation. As I retracted the gear; the airplane started a violent roll to the right. The First Officer applied full opposite aileron. I pushed the yoke forward and simultaneously said 'push the nose down'. The airplane started to reduce bank and climb normally. By this time we were over the parallel taxiway east of [Runway] 1R correcting heading and noticing that LNAV had failed and we couldn't restore it. The First Officer flew raw data on the map until we were able to restore LNAV shortly after. We also noticed a big white flashing box around the engine instruments' indications showing oil quantity low and depleting. It wound up being a classic case of oil gulping for the Number 1 Engine; but it was eye opening with all the other occurrences. The engine oil indication started [to] replenish 30 to 40 seconds later. We continued to climb and landed uneventfully. We had two inquiries regarding the departure; one from our A Flight Attendant who noticed the unusual attitude; and a couple from passengers in the back of the aircraft; one of whom was a private pilot and asked if we encountered wake turbulence. The First Officer was at the controls the entire time and did an excellent job of recovering from the wake turbulence. Preventative Measures: The obvious is that we could have delayed takeoff and left more spacing. ATC could do the same. The reality is that they are trying to move metal as quickly as we are and both of us are mission-oriented. The preceding airplane was not a heavy so they and we complied with all procedures. It is apparent to me that the B737-700 wing produces a more significant wake vortices than other models. I don't know if it's because of wing shape or the heavier gross weights the aircraft is capable of taking off at. Some consideration should be given to researching the actual wake the airplane produces and coordinating departure spacing with ATC accordingly.
Data retrieved from NASA's ASRS site as of July 2013 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.