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A B737-800 on approach is unable to extend the nose gear normally and required manual extension. Caused by a failed gear down line hydraulic fuse.
| Attributes | |
| ACN | 508533 |
| Time | |
| Date | 200104 |
| Day | Wed |
| Local Time Of Day | 1801 To 2400 |
| Place | |
| Locale Reference | airport : zzz.airport |
| State Reference | US |
| Altitude | msl single value : 2500 |
| Environment | |
| Flight Conditions | VMC |
| Light | Dusk |
| Aircraft 1 | |
| Controlling Facilities | tracon : zzz.tracon |
| Operator | common carrier : air carrier |
| Make Model Name | B737-800 |
| Operating Under FAR Part | Part 121 |
| Navigation In Use | ils localizer only : 5r |
| Flight Phase | descent : approach |
| Route In Use | approach : instrument precision |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | company : air carrier |
| Function | flight crew : captain oversight : pic |
| Qualification | pilot : flight engineer pilot : multi engine pilot : commercial pilot : atp pilot : instrument |
| Experience | flight time last 90 days : 175 flight time total : 13600 flight time type : 4500 |
| ASRS Report | 508533 |
| Person 2 | |
| Affiliation | company : air carrier |
| Function | flight crew : first officer |
| Events | |
| Anomaly | aircraft equipment problem : critical other anomaly other |
| Independent Detector | aircraft equipment other aircraft equipment : nose gear position and warning other flight crewa other flight crewb |
| Resolutory Action | flight crew : declared emergency flight crew : overcame equipment problem |
| Consequence | other |
| Supplementary | |
| Problem Areas | Aircraft Company |
| Primary Problem | Aircraft |
Narrative:
The nose gear on the 737-800 would not extend normally when putting the gear handle down. Following the QRH, the nosegear was extended manually and a normal approach and landing was made. (Made a go around after the gear would not extend normally the first time.) this problem is not uncommon on the new generation 737's (600-700-800), apparently, this aircraft had not yet been modified by boeing to correct the known problem in the nose gear down line. Callback conversation with reporter revealed the following information: the reporter stated the B737-600, 700 and 800 models are experiencing problems with the hydraulic fuse located in the nose landing gear extend pressure line. The reporter said the problem is the fuse senses air and will then shut down hydraulic flow to extend cylinder. The reporter said there is a modification that corrects the problem, but this airplane was not modified. The reporter stated three reports of this type of failure including this incident have been reported recently on this carrier.
Original NASA ASRS Text
Title: A B737-800 ON APCH IS UNABLE TO EXTEND THE NOSE GEAR NORMALLY AND REQUIRED MANUAL EXTENSION. CAUSED BY A FAILED GEAR DOWN LINE HYDRAULIC FUSE.
Narrative: THE NOSE GEAR ON THE 737-800 WOULD NOT EXTEND NORMALLY WHEN PUTTING THE GEAR HANDLE DOWN. FOLLOWING THE QRH, THE NOSEGEAR WAS EXTENDED MANUALLY AND A NORMAL APCH AND LNDG WAS MADE. (MADE A GAR AFTER THE GEAR WOULD NOT EXTEND NORMALLY THE FIRST TIME.) THIS PROB IS NOT UNCOMMON ON THE NEW GENERATION 737'S (600-700-800), APPARENTLY, THIS ACFT HAD NOT YET BEEN MODIFIED BY BOEING TO CORRECT THE KNOWN PROBLEM IN THE NOSE GEAR DOWN LINE. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTR STATED THE B737-600, 700 AND 800 MODELS ARE EXPERIENCING PROBS WITH THE HYDRAULIC FUSE LOCATED IN THE NOSE LNDG GEAR EXTEND PRESSURE LINE. THE RPTR SAID THE PROB IS THE FUSE SENSES AIR AND WILL THEN SHUT DOWN HYDRAULIC FLOW TO EXTEND CYLINDER. THE RPTR SAID THERE IS A MODIFICATION THAT CORRECTS THE PROB, BUT THIS AIRPLANE WAS NOT MODIFIED. THE RPTR STATED THREE RPTS OF THIS TYPE OF FAILURE INCLUDING THIS INCIDENT HAVE BEEN RPTED RECENTLY ON THIS CARRIER.
Data retrieved from NASA's ASRS site as of July 2007 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.