Rattling and Roll During Takeoff
08-06-2011, 03:21 PM
#1
New Hire
Thread Starter
Joined APC: Aug 2011
Posts: 2
Rattling and Roll During Takeoff
Hello everyone, first time post.
I'm not a pilot, just a flier that hasn't been able to find out what may have happened on a recent flight anywhere online. Hopefully this is the right place?
Anyways, I fly maybe a dozen times a year, but never on a 737-800 (which is the plane in question). The flight was Salt Lake to San Diego, DL1995, leaving at 10 pm. While taxi-ing, I noticed that the engines seemed to spool for a couple seconds before moving, noticeably longer than the previous flights I have been on (this may be completely normal, I normally fly on Southwest 737-300s). We had to wait awhile to take off, taxi-ing behind other planes.
When taking off, immediately as we were leaving the ground (I believe just the front wheel was off the ground), there was a VERY lound metallic rattling from the left side of the plane. It was clearly outside the plane (not luggage racks or anything) and much louder than the engines. As we continued to liftoff, the noise continued for a few seconds longer. As soon as the rattling stopped, the plane immediately rolled sharply to the left before correctly abruptly. This was all VERY noticeable and several people screamed/gasped/started crying. For the entire rest of the flight until after landing no announcements were made by the pilots on the PA system, it was always the flight attendents (the pilots had made the usually announcements while taxi-ing about the weather, flight duration, etc).
The rest of the flight was relatively unremarkable, except we did arrive in San Diego about 30 minutes early. Stopping was definitely longer than other flights I'd been on, but not super-remarkably so.
Any ideas on what happened? I wanted to ask at the time, but assumed I would not get any real answer, if anyone even knew.
I'm not a pilot, just a flier that hasn't been able to find out what may have happened on a recent flight anywhere online. Hopefully this is the right place?
Anyways, I fly maybe a dozen times a year, but never on a 737-800 (which is the plane in question). The flight was Salt Lake to San Diego, DL1995, leaving at 10 pm. While taxi-ing, I noticed that the engines seemed to spool for a couple seconds before moving, noticeably longer than the previous flights I have been on (this may be completely normal, I normally fly on Southwest 737-300s). We had to wait awhile to take off, taxi-ing behind other planes.
When taking off, immediately as we were leaving the ground (I believe just the front wheel was off the ground), there was a VERY lound metallic rattling from the left side of the plane. It was clearly outside the plane (not luggage racks or anything) and much louder than the engines. As we continued to liftoff, the noise continued for a few seconds longer. As soon as the rattling stopped, the plane immediately rolled sharply to the left before correctly abruptly. This was all VERY noticeable and several people screamed/gasped/started crying. For the entire rest of the flight until after landing no announcements were made by the pilots on the PA system, it was always the flight attendents (the pilots had made the usually announcements while taxi-ing about the weather, flight duration, etc).
The rest of the flight was relatively unremarkable, except we did arrive in San Diego about 30 minutes early. Stopping was definitely longer than other flights I'd been on, but not super-remarkably so.
Any ideas on what happened? I wanted to ask at the time, but assumed I would not get any real answer, if anyone even knew.
08-06-2011, 05:58 PM
#2
Gets Weekends Off
Joined APC: Feb 2008
Position: Cessna 150
Posts: 655
First off, my disclaimer: I was not there so I will comment based on speculation only to ease your concern.
Sometimes, due to tire wear, the nose wheel assembly can become slightly unbalanced. Also, because of the altitude of the SLC airport, the airplane may have to be accelerated to a higher ground speed for takeoff than other lower altitude airports. Those two things combined with the small diameter of a nosewheel at 140-150 knots (estimates) can create a loud vibration originating at the nose gear once it is lifted off the ground.
You also mentioned that you were in line behind other airplanes waiting for takeoff. From what you described, this sounds like the classic wake turbulence encounter. Again, my disclaimer: I wasn't there.
Sometimes, due to tire wear, the nose wheel assembly can become slightly unbalanced. Also, because of the altitude of the SLC airport, the airplane may have to be accelerated to a higher ground speed for takeoff than other lower altitude airports. Those two things combined with the small diameter of a nosewheel at 140-150 knots (estimates) can create a loud vibration originating at the nose gear once it is lifted off the ground.
You also mentioned that you were in line behind other airplanes waiting for takeoff. From what you described, this sounds like the classic wake turbulence encounter. Again, my disclaimer: I wasn't there.
08-06-2011, 06:45 PM
#3
Moderator
Joined APC: Mar 2007
Position: Tiki bar
Posts: 2,634
Anyways, I fly maybe a dozen times a year, but never on a 737-800 (which is the plane in question). The flight was Salt Lake to San Diego, DL1995, leaving at 10 pm. While taxi-ing, I noticed that the engines seemed to spool for a couple seconds before moving, noticeably longer than the previous flights I have been on (this may be completely normal, I normally fly on Southwest 737-300s). We had to wait awhile to take off, taxi-ing behind other planes.
When taking off, immediately as we were leaving the ground (I believe just the front wheel was off the ground), there was a VERY lound metallic rattling from the left side of the plane. It was clearly outside the plane (not luggage racks or anything) and much louder than the engines. As we continued to liftoff, the noise continued for a few seconds longer. As soon as the rattling stopped, the plane immediately rolled sharply to the left before correctly abruptly. This was all VERY noticeable and several people screamed/gasped/started crying. For the entire rest of the flight until after landing no announcements were made by the pilots on the PA system, it was always the flight attendents (the pilots had made the usually announcements while taxi-ing about the weather, flight duration, etc).
The rest of the flight was relatively unremarkable, except we did arrive in San Diego about 30 minutes early. Stopping was definitely longer than other flights I'd been on, but not super-remarkably so.
Any ideas on what happened? I wanted to ask at the time, but assumed I would not get any real answer, if anyone even knew.
The bank you described is probably a result of wake turbulence (caused by the previous aircraft's wings generating lift) or mechanical turbulence (caused by the drag generated from wind passing over/around trees, buildings, etc.). Again, perfectly normal and quickly corrected by the flying pilot, as you described.
These are just best guesses, as I wasn't there. However, what you describe seems to fit these descriptions best and are perfectly normal occurrences. Hope this helps.
08-07-2011, 10:13 AM
#4
New Hire
Thread Starter
Joined APC: Aug 2011
Posts: 2
Thanks guys, the nose assembly seems like it was definitely the issue. Using that, I was actually able to find a video online with a similar noise:
‪Strange noise on takeoff AA 737-800 MIA‬‏ - YouTube
Anyways, thanks again. I wasn't particularly worried as I know planes can survive pretty dramatic failures, I was just curious and found it very difficult to find any answers online. It seems like every website assumes people are freaking out about the air vents or just landing gear going up/down.
‪Strange noise on takeoff AA 737-800 MIA‬‏ - YouTube
Anyways, thanks again. I wasn't particularly worried as I know planes can survive pretty dramatic failures, I was just curious and found it very difficult to find any answers online. It seems like every website assumes people are freaking out about the air vents or just landing gear going up/down.
