If this is your first visit, be sure to check out the FAQ by clicking the link above. You may have to register before you can post: click the register link above to proceed. To start viewing messages, select the forum that you want to visit from the selection below. |
|
|
Thread Tools | Display Modes |
#1
|
|||
|
|||
Multi engine fuel crossfeed question (Duchess twin)
Hi All, I'm working on my multi rating in a Beech Duchess. I'm
curious about an item that doesn't seem well covered in the POH and elsewhere for that matter. What if you loose one engine at altitude, allowing plenty of time to try to fix. You determine that you ran the right tank dry of fuel. According to the fuel diagram, you should be able to run both engines off one tank. The fuel line exits each tank and splits: one going to the opposite fuel selector and one going to the closest engines fuel selector. If this is doable, why is it not talked about more? It's not a "fix" option on the checklist and not discussed in the text of the POH. Crossfeed is considered an emergency operation according to the POH, and also "level flight only". Could this be why? Possible fuel starvation on the crossfeeding engine from maneuvering to land, where it may be safer to feather and secure the dead engine and do your one shot landing. .... akiley |
#2
|
|||
|
|||
Multi engine fuel crossfeed question (Duchess twin)
|
#3
|
|||
|
|||
Multi engine fuel crossfeed question (Duchess twin)
On Jan 14, 3:33 pm, Bertie the Bunyip wrote:
akiley wrote in news:2e7dbffb-645c-49b6-9687- : Hi All, I'm working on my multi rating in a Beech Duchess. I'm curious about an item that doesn't seem well covered in the POH and elsewhere for that matter. What if you loose one engine at altitude, allowing plenty of time to try to fix. You determine that you ran the right tank dry of fuel. According to the fuel diagram, you should be able to run both engines off one tank. The fuel line exits each tank and splits: one going to the opposite fuel selector and one going to the closest engines fuel selector. If this is doable, why is it not talked about more? It's not a "fix" option on the checklist and not discussed in the text of the POH. Crossfeed is considered an emergency operation according to the POH, and also "level flight only". Could this be why? Possible fuel starvation on the crossfeeding engine from maneuvering to land, where it may be safer to feather and secure the dead engine and do your one shot landing. ... akiley I have no idea what you're asking here. If you've lost an engine, why would you be needing to run both off one tank? Now, if you mean that you still have a long way to go and that you'll run one dry before you get where you are going, then , yes, that's what it's for. You also want to alternate a bit to keep any imbalance from getting crazy. I haven't flown a duchss n a long time, but I don't remember there being anything too strange about the crossfeed arrangements. But if you lost one there's nothing stopping you from crossfeeding from the oppostie tank. Likelywise, if you have a leak in one tank, there's no reason I can see you can't run both engines off of the remaining tank. Sounds like they are (quite rightfully) discouraging 2recreational crossfeeding" that some guys do just to "balance em out perfectly" This usually leads to a massive imbalance, or even worse, having both engines flame out due to ou getting distracted and forgetting. It happens. Bertie In essence, I was asking if there was any reason not to run both engines off one tank. In singles, "switch tanks" always seems to be part of the emergency checklist for a rough engine, yet in the Duchess POH (and a Seneca I for that matter) "crossfeed" isn't mentioned as a diagnostic step where it seems like is should be. I was wondering if I had missed something. ... Akiley |
#4
|
|||
|
|||
Multi engine fuel crossfeed question (Duchess twin)
akiley wrote in
: On Jan 14, 3:33 pm, Bertie the Bunyip wrote: akiley wrote in news:2e7dbffb-645c-49b6-9687- : Hi All, I'm working on my multi rating in a Beech Duchess. I'm curious about an item that doesn't seem well covered in the POH and elsewhere for that matter. What if you loose one engine at altitude, allowing plenty of time to try to fix. You determine that you ran the right tank dry of fuel. According to the fuel diagram, you should be able to run both engines off one tank. The fuel line exits each tank and splits: one going to the opposite fuel selector and one going to the closest engines fuel selector. If this is doable, why is it not talked about more? It's not a "fix" option on the checklist and not discussed in the text of the POH. Crossfeed is considered an emergency operation according to the POH, and also "level flight only". Could this be why? Possible fuel starvation on the crossfeeding engine from maneuvering to land, where it may be safer to feather and secure the dead engine and do your one shot landing. ... akiley I have no idea what you're asking here. If you've lost an engine, why would you be needing to run both off one tank? Now, if you mean that you still have a long way to go and that you'll run one dry before you get where you are going, then , yes, that's what it's for. You also want to alternate a bit to keep any imbalance from getting crazy. I haven't flown a duchss n a long time, but I don't remember there being anything too strange about the crossfeed arrangements. But if you lost one there's nothing stopping you from crossfeeding from the oppostie tank. Likelywise, if you have a leak in one tank, there's no reason I can see you can't run both engines off of the remaining tank. Sounds like they are (quite rightfully) discouraging 2recreational crossfeeding" that some guys do just to "balance em out perfectly" This usually leads to a massive imbalance, or even worse, having both engines flame out due to ou getting distracted and forgetting. It happens. Bertie In essence, I was asking if there was any reason not to run both engines off one tank. In singles, "switch tanks" always seems to be part of the emergency checklist for a rough engine, yet in the Duchess POH (and a Seneca I for that matter) "crossfeed" isn't mentioned as a diagnostic step where it seems like is should be. I was wondering if I had missed something. OK, if I'm following you, you're suggesting that you've lost an engine for no apparent reason. You decide that it might be a fuel problem, so you want to feed off the tank on the opposite side to see if that fixes it. Sounds like a good idea to me. You would have to be very, very careful that it wasn't a fuel line on the failed side that caused the problem in the first place, otherwise you could lose all the fuel. That's what happened to that A330 that deadsticked into the Azores. But it sounds like a reasonable thng to do if that is what you suspect the problem is. Just make sure you do it slowly and deliberately. you don't want to end up gliding due to a poor selection. You might also consider, on the day, the wisdom of relighting an engine with a fuel problem. It's all a trade off of various risks. Wx, how far you have to go vs how much gas you got left, that sort of stuff. If you don't really need it to get where you are going, it might be better not to take the risk. If you are in the middle of a mountain range and you need it to keep your altitude above MORA at night, different story. Not that you should be there anyway. Manufacturers, the FAA and schools will steer you towards the checklists and procedures for some very good reasons. Experience with some of these situations has produced a pattern of th emost likely causes and the results of getting too creative with the systems. If they recommend you do something a certain way, do it that way. But, if you 're off the page, knowing how the system works will enable you to analyse the problem with a good chance of a solution. Bertie |
#5
|
|||
|
|||
Multi engine fuel crossfeed question (Duchess twin)
On Jan 14, 4:52 pm, Bertie the Bunyip wrote:
akiley wrote : On Jan 14, 3:33 pm, Bertie the Bunyip wrote: akiley wrote in news:2e7dbffb-645c-49b6-9687- : Hi All, I'm working on my multi rating in a Beech Duchess. I'm curious about an item that doesn't seem well covered in the POH and elsewhere for that matter. What if you loose one engine at altitude, allowing plenty of time to try to fix. You determine that you ran the right tank dry of fuel. According to the fuel diagram, you should be able to run both engines off one tank. The fuel line exits each tank and splits: one going to the opposite fuel selector and one going to the closest engines fuel selector. If this is doable, why is it not talked about more? It's not a "fix" option on the checklist and not discussed in the text of the POH. Crossfeed is considered an emergency operation according to the POH, and also "level flight only". Could this be why? Possible fuel starvation on the crossfeeding engine from maneuvering to land, where it may be safer to feather and secure the dead engine and do your one shot landing. ... akiley I have no idea what you're asking here. If you've lost an engine, why would you be needing to run both off one tank? Now, if you mean that you still have a long way to go and that you'll run one dry before you get where you are going, then , yes, that's what it's for. You also want to alternate a bit to keep any imbalance from getting crazy. I haven't flown a duchss n a long time, but I don't remember there being anything too strange about the crossfeed arrangements. But if you lost one there's nothing stopping you from crossfeeding from the oppostie tank. Likelywise, if you have a leak in one tank, there's no reason I can see you can't run both engines off of the remaining tank. Sounds like they are (quite rightfully) discouraging 2recreational crossfeeding" that some guys do just to "balance em out perfectly" This usually leads to a massive imbalance, or even worse, having both engines flame out due to ou getting distracted and forgetting. It happens. Bertie In essence, I was asking if there was any reason not to run both engines off one tank. In singles, "switch tanks" always seems to be part of the emergency checklist for a rough engine, yet in the Duchess POH (and a Seneca I for that matter) "crossfeed" isn't mentioned as a diagnostic step where it seems like is should be. I was wondering if I had missed something. OK, if I'm following you, you're suggesting that you've lost an engine for no apparent reason. You decide that it might be a fuel problem, so you want to feed off the tank on the opposite side to see if that fixes it. Sounds like a good idea to me. You would have to be very, very careful that it wasn't a fuel line on the failed side that caused the problem in the first place, otherwise you could lose all the fuel. That's what happened to that A330 that deadsticked into the Azores. But it sounds like a reasonable thng to do if that is what you suspect the problem is. Just make sure you do it slowly and deliberately. you don't want to end up gliding due to a poor selection. You might also consider, on the day, the wisdom of relighting an engine with a fuel problem. It's all a trade off of various risks. Wx, how far you have to go vs how much gas you got left, that sort of stuff. If you don't really need it to get where you are going, it might be better not to take the risk. If you are in the middle of a mountain range and you need it to keep your altitude above MORA at night, different story. Not that you should be there anyway. Manufacturers, the FAA and schools will steer you towards the checklists and procedures for some very good reasons. Experience with some of these situations has produced a pattern of th emost likely causes and the results of getting too creative with the systems. If they recommend you do something a certain way, do it that way. But, if you 're off the page, knowing how the system works will enable you to analyse the problem with a good chance of a solution. Bertie Thanks for the good point. Remember in the original post I made a scenario where I exhausted the fuel in the right tank. Fuel pressure and quantity gauges confirmed this. So I decide to try to crossfeed from the good engine side to the engine that I lost due to fuel starvation. But good point. What if I lost all the fuel in that tank because of some problems like a leak that may effect the full tank if I crossfeed. .... akiley |
#6
|
|||
|
|||
Multi engine fuel crossfeed question (Duchess twin)
|
#7
|
|||
|
|||
Multi engine fuel crossfeed question (Duchess twin)
On Jan 14, 6:37 pm, Bertie the Bunyip wrote:
akiley wrote : On Jan 14, 4:52 pm, Bertie the Bunyip wrote: akiley wrote innews:5c24ef75-4385-4897-a75d- om: On Jan 14, 3:33 pm, Bertie the Bunyip wrote: akiley wrote in news:2e7dbffb-645c-49b6-9687- : Hi All, I'm working on my multi rating in a Beech Duchess. I'm curious about an item that doesn't seem well covered in the POH and elsewhere for that matter. What if you loose one engine at altitude, allowing plenty of time to try to fix. You determine that you ran the right tank dry of fuel. According to the fuel diagram, you should be able to run both engines off one tank. The fuel line exits each tank and splits: one going to the opposite fuel selector and one going to the closest engines fuel selector. If this is doable, why is it not talked about more? It's not a "fix" option on the checklist and not discussed in the text of the POH. Crossfeed is considered an emergency operation according to the POH, and also "level flight only". Could this be why? Possible fuel starvation on the crossfeeding engine from maneuvering to land, where it may be safer to feather and secure the dead engine and do your one shot landing. ... akiley I have no idea what you're asking here. If you've lost an engine, why would you be needing to run both off one tank? Now, if you mean that you still have a long way to go and that you'll run one dry before you get where you are going, then , yes, that's what it's for. You also want to alternate a bit to keep any imbalance from getting crazy. I haven't flown a duchss n a long time, but I don't remember there being anything too strange about the crossfeed arrangements. But if you lost one there's nothing stopping you from crossfeeding from the oppostie tank. Likelywise, if you have a leak in one tank, there's no reason I can see you can't run both engines off of the remaining tank. Sounds like they are (quite rightfully) discouraging 2recreational crossfeeding" that some guys do just to "balance em out perfectly" This usually leads to a massive imbalance, or even worse, having both engines flame out due to ou getting distracted and forgetting. It happens. Bertie In essence, I was asking if there was any reason not to run both engines off one tank. In singles, "switch tanks" always seems to be part of the emergency checklist for a rough engine, yet in the Duchess POH (and a Seneca I for that matter) "crossfeed" isn't mentioned as a diagnostic step where it seems like is should be. I was wondering if I had missed something. OK, if I'm following you, you're suggesting that you've lost an engine for no apparent reason. You decide that it might be a fuel problem, so you want to feed off the tank on the opposite side to see if that fixes it. Sounds like a good idea to me. You would have to be very, very careful that it wasn't a fuel line on the failed side that caused the problem in the first place, otherwise you could lose all the fuel. That's what happened to that A330 that deadsticked into the Azores. But it sounds like a reasonable thng to do if that is what you suspect the problem is. Just make sure you do it slowly and deliberately. you don't want to end up gliding due to a poor selection. You might also consider, on the day, the wisdom of relighting an engine with a fuel problem. It's all a trade off of various risks. Wx, how far you have to go vs how much gas you got left, that sort of stuff. If you don't really need it to get where you are going, it might be better not to take the risk. If you are in the middle of a mountain range and you need it to keep your altitude above MORA at night, different story. Not that you should be there anyway. Manufacturers, the FAA and schools will steer you towards the checklists and procedures for some very good reasons. Experience with some of these situations has produced a pattern of th emost likely causes and the results of getting too creative with the systems. If they recommend you do something a certain way, do it that way. But, if you 're off the page, knowing how the system works will enable you to analyse the problem with a good chance of a solution. Bertie Thanks for the good point. Remember in the original post I made a scenario where I exhausted the fuel in the right tank. Fuel pressure and quantity gauges confirmed this. So I decide to try to crossfeed from the good engine side to the engine that I lost due to fuel starvation. But good point. What if I lost all the fuel in that tank because of some problems like a leak that may effect the full tank if I crossfeed. If you exhausted the fuel in one tank with a simple system like a Duchess or Seneca has, it can only be because there wasn't much to begin with ( you wouldn't do that, right) or because it's spilling out somewhere it shouldn't. If you can see it coming out of the tank ( left the cap off? ) then you might have a case for x-feeding. If not, it might be leaking downstream of where the other tank joins into the failed side's fuel system. One other reason you might not be getting fuel is a failed fuel pump. Maybe both the elec and mech pump is gone on one side. The elec pump on th eoposite side should be able to pressurise the fuel system on the opposite side. It did in at least one airplane I have flown. Very unlikely, I know, but it could be and this one has happened to me once in a twin Beech on the ground. I seem to recall some twins had problems with fuel lines chafing, which cased the fuel line to rupture draining the tank into the wing area behind the engine somewhere. Maybe you wouldn't want to try to restart that failed engine using crossfeed! Also, can't a clogged fuel tank vent cause a vacuum, then fuel starvation? So maybe the aircraft manufacturer doesn't want to suggest the option of restarting a failed engine by crossfeeding from the opposite engine because: It might be dangerous in some cases like you mention. Fuel leaking internally. Maybe securing that failed engine, which turns off fuel and electricity on that side is a safer option. .... akiley |
#8
|
|||
|
|||
Multi engine fuel crossfeed question (Duchess twin)
akiley wrote in
: I seem to recall some twins had problems with fuel lines chafing, which cased the fuel line to rupture draining the tank into the wing area behind the engine somewhere. Haven't heard of it but I'd be surprised if it hadn't happened somewhere, sometime. Maybe you wouldn't want to try to restart that failed engine using crossfeed! Also, can't a clogged fuel tank vent cause a vacuum, then fuel starvation? Yep! So maybe the aircraft manufacturer doesn't want to suggest the option of restarting a failed engine by crossfeeding from the opposite engine because: It might be dangerous in some cases like you mention. Fuel leaking internally. Maybe securing that failed engine, which turns off fuel and electricity on that side is a safer option. Well, they did provide you with a crossfeed! You do what you have to do, but you'd want to be sure of what it is you're doing. If you needed the engine to keep you from hitting somethng, the ground, for instance, then you don't have a lot of choice. So it all depends. You might know for sure why it shut down. Hard to say even when you;re sitting there next to the engine. In jets it's something we might consider a bit more seriously since they can flame out just from very heavy rain, for instance ( shouldn't, though) We're trained to attempt a restart if there's no apparent damage to the engine, but we're not trained to try and see if fuel from the opposite tank will fix it. If the tank on that side has run dry, I'd be just as wary of a restart never mind one from the other tank as I would in a light twin for the same reason you stated. But if I knew why the fuel was gone and it wasn't dangerous to restart and I was very sure of that, well then, sure, I'd attempt a restart and I would use the fuel from the opposite tank. Bertie |
#9
|
|||
|
|||
Multi engine fuel crossfeed question (Duchess twin)
On Jan 14, 11:07 pm, Bertie the Bunyip wrote:
wrote : I seem to recall some twins had problems with fuel lines chafing, which cased the fuel line to rupture draining the tank into the wing area behind the engine somewhere. Haven't heard of it but I'd be surprised if it hadn't happened somewhere, sometime. Maybe you wouldn't want to try to restart that failed engine using crossfeed! Also, can't a clogged fuel tank vent cause a vacuum, then fuel starvation? Yep! So maybe the aircraft manufacturer doesn't want to suggest the option of restarting a failed engine by crossfeeding from the opposite engine because: It might be dangerous in some cases like you mention. Fuel leaking internally. Maybe securing that failed engine, which turns off fuel and electricity on that side is a safer option. Well, they did provide you with a crossfeed! You do what you have to do, but you'd want to be sure of what it is you're doing. If you needed the engine to keep you from hitting somethng, the ground, for instance, then you don't have a lot of choice. So it all depends. You might know for sure why it shut down. Hard to say even when you;re sitting there next to the engine. In jets it's something we might consider a bit more seriously since they can flame out just from very heavy rain, for instance ( shouldn't, though) We're trained to attempt a restart if there's no apparent damage to the engine, but we're not trained to try and see if fuel from the opposite tank will fix it. If the tank on that side has run dry, I'd be just as wary of a restart never mind one from the other tank as I would in a light twin for the same reason you stated. But if I knew why the fuel was gone and it wasn't dangerous to restart and I was very sure of that, well then, sure, I'd attempt a restart and I would use the fuel from the opposite tank. Bertie Good points, I think I have a better understanding of the situation now. Thanks ... akiley |
#10
|
|||
|
|||
Multi engine fuel crossfeed question (Duchess twin)
akiley wrote in
: On Jan 14, 11:07 pm, Bertie the Bunyip wrote: wrote innews:f4c009c3-4d05-46f4-9ceb-c54f686f33d7 @e25g2000prg.googlegroups.c om: I seem to recall some twins had problems with fuel lines chafing, which cased the fuel line to rupture draining the tank into the wing area behind the engine somewhere. Haven't heard of it but I'd be surprised if it hadn't happened somewhere, sometime. Maybe you wouldn't want to try to restart that failed engine using crossfeed! Also, can't a clogged fuel tank vent cause a vacuum, then fuel starvation? Yep! So maybe the aircraft manufacturer doesn't want to suggest the option of restarting a failed engine by crossfeeding from the opposite engine because: It might be dangerous in some cases like you mention. Fuel leaking internally. Maybe securing that failed engine, which turns off fuel and electricity on that side is a safer option. Well, they did provide you with a crossfeed! You do what you have to do, but you'd want to be sure of what it is you're doing. If you needed the engine to keep you from hitting somethng, the ground, for instance, then you don't have a lot of choice. So it all depends. You might know for sure why it shut down. Hard to say even when you;re sitting there next to the engine. In jets it's something we might consider a bit more seriously since they can flame out just from very heavy rain, for instance ( shouldn't, though) We're trained to attempt a restart if there's no apparent damage to the engine, but we're not trained to try and see if fuel from the opposite tank will fix it. If the tank on that side has run dry, I'd be just as wary of a restart never mind one from the other tank as I would in a light twin for the same reason you stated. But if I knew why the fuel was gone and it wasn't dangerous to restart and I was very sure of that, well then, sure, I'd attempt a restart and I would use the fuel from the opposite tank. Bertie Good points, I think I have a better understanding of the situation now. Kay! Probably more than you wanted to know, but it's hard to tell exactly what someone wants to know here! Bertie |
Thread Tools | |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Thread Starter | Forum | Replies | Last Post |
CFII or multi-engine? | Casey Hansen | Piloting | 3 | April 23rd 04 12:57 AM |
Multi-Engine Before Commercial? | David B. Cole | Piloting | 30 | April 18th 04 04:46 PM |
Time Building Multi Engine | Midway Aviators | Aviation Marketplace | 0 | March 9th 04 04:57 AM |
multi engine ultralight trainers | [email protected] | Owning | 0 | January 1st 04 07:10 PM |
Multi-Engine which one ? | B25flyer | Piloting | 4 | December 11th 03 06:43 PM |