Some questions about high-speed R/TO
09-21-2013 | 12:48 AM
#1
Thread Starter
On Reserve
Joined: Feb 2013
Posts: 10
Likes: 0
Some questions about high-speed R/TO
I have flown B737 for a coup of years. Most R/TOs that I've ever learnt so far in our company were all initiated at low speed. And most of them turned out to be false alarms, like "speed disagree" indication, "door" annunciation, etc. During our SIM training, we stick with the QRH. But none of us got real ideas what will happen after a high speed R/TO. The QRH says the wheel fuse plugs will melt. But what damage could these melting plugs bring to gear structure? If those plugs melt, can we still taxi? 
And why we can't set the parking brake unless passenger evacuation is necessary? Is it to prevent some potential fire hazard? I would really like to hear some real stories from members of this community and get my puzzles sorted out. Big thanks !
And why we can't set the parking brake unless passenger evacuation is necessary? Is it to prevent some potential fire hazard? I would really like to hear some real stories from members of this community and get my puzzles sorted out. Big thanks !
09-21-2013 | 02:52 AM
#2
On Reserve
Joined: Sep 2013
Posts: 17
Likes: 0
From: Navy EP-3 Pilot
I can't speak for the 737 specifically, but if the fuse plugs melt, I believe the tires will go flat to prevent them from blowing out. I would not taxi after that.
As for not setting the parking brakes unless pax have to evacuate. That is to prevent hot brakes from melting closed, or applied, and to help prevent them from catching fire.
I have never seen the fuzes go, but I have seen hot brakes that melted closed. Took maint a week to get them fixed.
As for not setting the parking brakes unless pax have to evacuate. That is to prevent hot brakes from melting closed, or applied, and to help prevent them from catching fire.
I have never seen the fuzes go, but I have seen hot brakes that melted closed. Took maint a week to get them fixed.
09-21-2013 | 03:23 AM
#3
Gets Weekends Off
Joined: Jul 2013
Posts: 218
Likes: 0
From: FAA ATSI VSRP ERC
I have flown B737 for a coup of years. Most R/TOs that I've ever learnt so far in our company were all initiated at low speed. And most of them turned out to be false alarms, like "speed disagree" indication, "door" annunciation, etc. During our SIM training, we stick with the QRH. But none of us got real ideas what will happen after a high speed R/TO. The QRH says the wheel fuse plugs will melt. But what damage could these melting plugs bring to gear structure? If those plugs melt, can we still taxi? And why we can't set the parking brake unless passenger evacuation is necessary? Is it to prevent some potential fire hazard? I would really like to hear some real stories from members of this community and get my puzzles sorted out. Big thanks !
And why we can't set the parking brake unless passenger evacuation is necessary? Is it to prevent some potential fire hazard? I would really like to hear some real stories from members of this community and get my puzzles sorted out. Big thanks !If you have ever tried to move an aircraft with 4 flats it would take quite amount of T/L input! If you did move the aircraft with flats, it can damage the brakes and surrounding structure (antiskid xducers, hyd lines, etc,). The reason for not setting the brakes is to prevent fire and to allow them to cool. On the bus, the carbon brakes can take the heat, but they take a long time to cool. Any of you who fly the aircraft in the summer know this, since you have probably had to wait for them to cool prior to pushback (or had a rather resourceful lead man use the A/C hose directed toward them to make an on-time departure) at one time or another. I also had a full 747-200F RTO at SFO with a full load. My crew ended up changing all 16 mains. We had to borrow tires from others to get this one back out. No comment on why this RTO happened.
Setting hot brakes causes all the heat to transfer to the axle, and to the bearings and other gear structure. Leaving them off allows the stacks of rotors to "breath" allowing them to cool more quickly.
I know of pilots who have taxied back to the gate quickly after an RTO knowing that fuses were going to melt. As soon as they got to the gate, the tires would start going. It was much easier to change them at the gate then on the taxiway, but for safety, I am not sure if that was a good idea.
One more thing; never, ever, approach an overtemped brake and or tire assy from the side. Always approach from the front or rear (direction of rotation). If you have ever seen one of them blow, you will understand. We always wait until the assemblies have sufficiently cooled to even attempt to do any maintenance on them.
Also, to change the tires after they all go flat, we used what is called a rhino jack...very low profile to under the jack point.
09-21-2013 | 06:22 AM
#4
Gets Weekends Off
Joined: Dec 2007
Posts: 992
Likes: 0
From: retired
As a former airline Lead Mechanic for 20+ years, I have dealt with several post high speed RTO aircraft. A couple were on the A-320 following an airspeed split caused by love bugs getting into the pitot tubes (in MCO) and causing flawed data being sent by the ADM. A couple for engine issues. Others for non-mechanical.
If you have ever tried to move an aircraft with 4 flats it would take quite amount of T/L input! If you did move the aircraft with flats, it can damage the brakes and surrounding structure (antiskid xducers, hyd lines, etc,). The reason for not setting the brakes is to prevent fire and to allow them to cool. On the bus, the carbon brakes can take the heat, but they take a long time to cool. Any of you who fly the aircraft in the summer know this, since you have probably had to wait for them to cool prior to pushback (or had a rather resourceful lead man use the A/C hose directed toward them to make an on-time departure) at one time or another. I also had a full 747-200F RTO at SFO with a full load. My crew ended up changing all 16 mains. We had to borrow tires from others to get this one back out. No comment on why this RTO happened.
Setting hot brakes causes all the heat to transfer to the axle, and to the bearings and other gear structure. Leaving them off allows the stacks of rotors to "breath" allowing them to cool more quickly.
I know of pilots who have taxied back to the gate quickly after an RTO knowing that fuses were going to melt. As soon as they got to the gate, the tires would start going. It was much easier to change them at the gate then on the taxiway, but for safety, I am not sure if that was a good idea.
One more thing; never, ever, approach an overtemped brake and or tire assy from the side. Always approach from the front or rear (direction of rotation). If you have ever seen one of them blow, you will understand. We always wait until the assemblies have sufficiently cooled to even attempt to do any maintenance on them.
Also, to change the tires after they all go flat, we used what is called a rhino jack...very low profile to under the jack point.
If you have ever tried to move an aircraft with 4 flats it would take quite amount of T/L input! If you did move the aircraft with flats, it can damage the brakes and surrounding structure (antiskid xducers, hyd lines, etc,). The reason for not setting the brakes is to prevent fire and to allow them to cool. On the bus, the carbon brakes can take the heat, but they take a long time to cool. Any of you who fly the aircraft in the summer know this, since you have probably had to wait for them to cool prior to pushback (or had a rather resourceful lead man use the A/C hose directed toward them to make an on-time departure) at one time or another. I also had a full 747-200F RTO at SFO with a full load. My crew ended up changing all 16 mains. We had to borrow tires from others to get this one back out. No comment on why this RTO happened.
Setting hot brakes causes all the heat to transfer to the axle, and to the bearings and other gear structure. Leaving them off allows the stacks of rotors to "breath" allowing them to cool more quickly.
I know of pilots who have taxied back to the gate quickly after an RTO knowing that fuses were going to melt. As soon as they got to the gate, the tires would start going. It was much easier to change them at the gate then on the taxiway, but for safety, I am not sure if that was a good idea.
One more thing; never, ever, approach an overtemped brake and or tire assy from the side. Always approach from the front or rear (direction of rotation). If you have ever seen one of them blow, you will understand. We always wait until the assemblies have sufficiently cooled to even attempt to do any maintenance on them.
Also, to change the tires after they all go flat, we used what is called a rhino jack...very low profile to under the jack point.
09-21-2013 | 06:23 AM
#5
Gets Weekends Off
Joined: Feb 2006
Posts: 6,248
Likes: 0
From: 767A (Ret)
Here's an account from Boeing about 747 RTO testing:
Boeing 747-8 performs ultimate rejected takeoff (Video)
Boeing 747-8 performs ultimate rejected takeoff (Video)
09-21-2013 | 08:49 AM
#6
Thread Starter
On Reserve
Joined: Feb 2013
Posts: 10
Likes: 0
To Mr. bilsch
As a former airline Lead Mechanic for 20+ years, I have dealt with several post high speed RTO aircraft. A couple were on the A-320 following an airspeed split caused by love bugs getting into the pitot tubes (in MCO) and causing flawed data being sent by the ADM. A couple for engine issues. Others for non-mechanical.
If you have ever tried to move an aircraft with 4 flats it would take quite amount of T/L input! If you did move the aircraft with flats, it can damage the brakes and surrounding structure (antiskid xducers, hyd lines, etc,). The reason for not setting the brakes is to prevent fire and to allow them to cool. On the bus, the carbon brakes can take the heat, but they take a long time to cool. Any of you who fly the aircraft in the summer know this, since you have probably had to wait for them to cool prior to pushback (or had a rather resourceful lead man use the A/C hose directed toward them to make an on-time departure) at one time or another. I also had a full 747-200F RTO at SFO with a full load. My crew ended up changing all 16 mains. We had to borrow tires from others to get this one back out. No comment on why this RTO happened.
Setting hot brakes causes all the heat to transfer to the axle, and to the bearings and other gear structure. Leaving them off allows the stacks of rotors to "breath" allowing them to cool more quickly.
I know of pilots who have taxied back to the gate quickly after an RTO knowing that fuses were going to melt. As soon as they got to the gate, the tires would start going. It was much easier to change them at the gate then on the taxiway, but for safety, I am not sure if that was a good idea.
One more thing; never, ever, approach an overtemped brake and or tire assy from the side. Always approach from the front or rear (direction of rotation). If you have ever seen one of them blow, you will understand. We always wait until the assemblies have sufficiently cooled to even attempt to do any maintenance on them.
Also, to change the tires after they all go flat, we used what is called a rhino jack...very low profile to under the jack point.
If you have ever tried to move an aircraft with 4 flats it would take quite amount of T/L input! If you did move the aircraft with flats, it can damage the brakes and surrounding structure (antiskid xducers, hyd lines, etc,). The reason for not setting the brakes is to prevent fire and to allow them to cool. On the bus, the carbon brakes can take the heat, but they take a long time to cool. Any of you who fly the aircraft in the summer know this, since you have probably had to wait for them to cool prior to pushback (or had a rather resourceful lead man use the A/C hose directed toward them to make an on-time departure) at one time or another. I also had a full 747-200F RTO at SFO with a full load. My crew ended up changing all 16 mains. We had to borrow tires from others to get this one back out. No comment on why this RTO happened.
Setting hot brakes causes all the heat to transfer to the axle, and to the bearings and other gear structure. Leaving them off allows the stacks of rotors to "breath" allowing them to cool more quickly.
I know of pilots who have taxied back to the gate quickly after an RTO knowing that fuses were going to melt. As soon as they got to the gate, the tires would start going. It was much easier to change them at the gate then on the taxiway, but for safety, I am not sure if that was a good idea.
One more thing; never, ever, approach an overtemped brake and or tire assy from the side. Always approach from the front or rear (direction of rotation). If you have ever seen one of them blow, you will understand. We always wait until the assemblies have sufficiently cooled to even attempt to do any maintenance on them.
Also, to change the tires after they all go flat, we used what is called a rhino jack...very low profile to under the jack point.
09-21-2013 | 08:57 AM
#7
Thread Starter
On Reserve
Joined: Feb 2013
Posts: 10
Likes: 0
To tomgoodman
Here's an account from Boeing about 747 RTO testing:
Boeing 747-8 performs ultimate rejected takeoff (Video)
Boeing 747-8 performs ultimate rejected takeoff (Video)
09-21-2013 | 09:23 AM
#8
Thread Starter
On Reserve
Joined: Feb 2013
Posts: 10
Likes: 0
To Mongo
Thread
Thread Starter
Forum
Replies
Last Post
