KingFriday013 From United States of America, joined May 2007, 1277 posts, RR: 10 Posted (2 years 2 months 1 week 1 hour ago) and read 7341 times:
Hey y'all,
I've been meaning to figure this out for a while, just did a search and couldn't find anything. What the heck is that fin/strake/whatever-you-wanna-call it thing on the Embraer 190/195? It's on the bottom, close to the rear. Here are a few pictures I found:
KELPkid From United States of America, joined Nov 2005, 5932 posts, RR: 4 Reply 1, posted (2 years 2 months 1 week ago) and read 7331 times:
On the AC E170's, it sure looks like a VHF antenna...probably for NAV and COM combined
Harder to tell on the US 190's. It looks like there's the same VHF antenna right at the front, but the dark paint sure makes the rest hard to pick out... looks like it might be a strake type thingy immediately aft of the antenna.
Celebrating the birth of KELPkidJR on August 5, 2009 :-)
Your LOC antenna (the localizer is half of the ILS system-the part that lines you up to the runway left-to-right) is going to be the same antenna as your NAV antenna, because localizers use the lower portion of the same frequency band that VOR's use. The glideslope antenna (glideslope is the up/down guidance on an ILS) is basically 1/3 the the size of the NAV/LOC antenna, because, IIRC, the glideslope transmitter frequency is about 3 times higher than LOC frequency, and, in fact, falls in the UHF frequency band (higher frequencies than the VHF bands used for navigation and communication).
GA aircraft which are IFR equipped have a somewhat longer antenna on the belly (that looks like a little ladder) for picking up the almost-obsolete marker beacons on an ILS (and marker beacons are being decomissioned by the droves here in the US). Airliners probably have marker beacon antennas, too, but in a lower-drag form.
Celebrating the birth of KELPkidJR on August 5, 2009 :-)
KingFriday013 From United States of America, joined May 2007, 1277 posts, RR: 10 Reply 5, posted (2 years 2 months 6 days 23 hours ago) and read 7286 times:
Quoting KELPkid (Reply 3): The more I delve into the topic, the more conviced I am that the strake-like appearance on the US E190's is an optical illusion:
Hmmm. I remember when I was taxiing by one I was thinking, "what the hell is that thing??" I think it's much more noticeable in real life, from the ground level (or at least from the window of a 737).
EMBQA From United States of America, joined Oct 2003, 9286 posts, RR: 13 Reply 6, posted (2 years 2 months 6 days 23 hours ago) and read 7279 times:
HSTA Compartment drain mast and fairing..................If you look at the photos that show the right side of the aircraft you'll see a 'dark' spot just below the horizontal stab fairing. That is the access door to this unpressurized area. The only thing in there is the System 3 Hydraulic pump and filters.... the HSTA ( Horizontal Stabiilizer Trim Actuactor ) .. and the hydraulic lines that feed the Elevators.
[Edited 2011-03-17 14:32:24]
"It's not the size of the dog in the fight, but the size of the fight in the dog"
B6JFKH81 From United States of America, joined Mar 2006, 2767 posts, RR: 7 Reply 7, posted (2 years 2 months 6 days 23 hours ago) and read 7271 times:
If you are referencing the item that runs along the bottom of the fuselage, from rear to front, it's actually a drain mast. Never really paid attention to it until this thread so I walked down to the hangar floor and (as usual) there is an E190 sitting out there. In speaking with an MX sup, he says its a drain for the very aft compartment (can figure out if it is forward or aft of the pressure bulk, I'm guessing forward since it looks like it comes from the compartment behind the galley carts) which houses a bunch of items and can get condensation in it. I have to check the drawings now LOL!
"If you do not learn from history, you are doomed to repeat it"
B6JFKH81 From United States of America, joined Mar 2006, 2767 posts, RR: 7 Reply 10, posted (2 years 2 months 6 days 23 hours ago) and read 7239 times:
Here is a better pic from UNDER an aircraft. It runs from back to front. EMBQA, is that exterior tubing leading to the mast? Where exactly does it drain from?
EMBQA From United States of America, joined Oct 2003, 9286 posts, RR: 13 Reply 11, posted (2 years 2 months 6 days 22 hours ago) and read 7232 times:
Yup Jason. Next time you're in the hangar stick your head in that door. The drain hole is right at the base of the pressure bulkhead. If you have hydraulic fluid coming out of it.. really-really bad things are happening, and you'll be getting an AOG call. Nashville Buddy.. schedule a trip.
"It's not the size of the dog in the fight, but the size of the fight in the dog"
B6JFKH81 From United States of America, joined Mar 2006, 2767 posts, RR: 7 Reply 12, posted (2 years 2 months 6 days 22 hours ago) and read 7224 times:
Quoting EMBQA (Reply 11): Yup Jason. Next time you're in the hangar stick your head in that door. The drain hole is right at the base of the pressure bulkhead. If you have hydraulic fluid coming out of it.. really-really bad things are happening, and you'll be getting an AOG call. Nashville Buddy.. schedule a trip.
Thank you, I'll poke my head in there after I finish eating dinner LOL. I would love to come down, but the amount of travel my crew is responsible for lately is insane. I did 26 cities last year, so a BNA HMV tour of duty was out of the question. Hopefully I can make it down on a ferry flight one day, chill, go out to eat, say hi to you guys, and pass ride back.
"If you do not learn from history, you are doomed to repeat it"
FlyASAGuy2005 From United States of America, joined Sep 2007, 6519 posts, RR: 11 Reply 13, posted (2 years 2 months 6 days 18 hours ago) and read 7157 times:
Okay, totally different a/c manufacturer but always wanted to ask this question.
What are the two "fin-like" objects that can be found on the CR9s?
In the pictures below, they are very noticeable located just aft section of the baggage compartment door.
Starlionblue From Hong Kong, joined Feb 2004, 15870 posts, RR: 66 Reply 15, posted (2 years 2 months 6 days 18 hours ago) and read 7148 times:
Quoting FlyASAGuy2005 (Reply 13): What are the two "fin-like" objects that can be found on the CR9s?
They're not "fin-like". They're fins!
On the subject of ventral fins, the F-8 Crusader had two since to counteract yaw moment at low speeds. I saw footage of one being catapulted off a carrier and immediately veering off to one side.
FlyASAGuy2005 From United States of America, joined Sep 2007, 6519 posts, RR: 11 Reply 16, posted (2 years 2 months 5 days 14 hours ago) and read 6909 times:
Quoting EMBQA (Reply 14): Ventral Fins... they help stabilize the aircraft in turns and lower speeds. They use the same thing on their Dash-8-400 design.
FlyASAGuy2005 From United States of America, joined Sep 2007, 6519 posts, RR: 11 Reply 19, posted (2 years 2 months 4 days 20 hours ago) and read 6714 times:
Quoting EMBQA (Reply 18): Maybe.. but I've seen them on several aircraft. Saab 340.. Saab 2000... EMB 145XR... EMB-135BJ just to name a few
Well, there you go! I guess it's more of a perfomance thing then.
CAM2:"Lightning coming out of that one." CAM1: "What?"
loggat From United States of America, joined Feb 2000, 660 posts, RR: 0 Reply 20, posted (2 years 2 months 3 days 1 hour ago) and read 6457 times:
Getting back to the original OP question, I fly the EMBs (170/175/190) for a living, and I have been told that the reason that this hydraulic system 3 drain makes the aircraft look like it has a fin is that when it was originally designed, the drain mast looked different (may even have been just a hole) and it was located on the bottom of the fuselage right below the aft compartment containing the system 3 hydraulic pumps and reservoir - ie. much closer to the tail. For some reason that I can only speculate (I think it has to do with the proximity of the original mast/hole to the APU air intake on the underside of the tail), they had to move the drain by creating a hollow fin structure to run the fluid down to the new (pictured) mast located a lot further forward and lower than the original. Basically it is a permanent fix to a problem detected during the original aircraft testing.
There are 3 types of people in this world, those that can count, and those that can't.
soon7x7 From United States of America, joined May 2006, 2799 posts, RR: 14 Reply 21, posted (2 years 1 month 4 weeks 1 day 19 hours ago) and read 6254 times:
Quoting FlyASAGuy2005 (Reply 16): Id this due to the length of the CR9? Don't think i've seen them on many other a/c.
I read that on CRJ's and Embraers the winglets create yaw instability so the ventral fins help to neutralize the effect.
zipsy From UK - England, joined Jul 2010, 37 posts, RR: 0 Reply 22, posted (9 months 3 weeks 1 day 19 hours ago) and read 4764 times:
Always wondered about this strange tubing on the E-Jets.On my last flight,on a 195,I have noticed that fluid came out of that mast,what does that mean?I saw it coming out when I entered the aircraft.There also was a strange smell in the cabin like burned oil or something like that.
KPWMSpotter From United States of America, joined Dec 2006, 325 posts, RR: 2 Reply 24, posted (9 months 3 weeks 1 day 8 hours ago) and read 4608 times:
Quoting tdscanuck (Reply 23): Something is leaking. The drain system is there to get leaking fluids safety out of the cabin (oil, fuel, hydraulic fluid, etc.).
Does the Embraer drain mast also vent lavatory grey water? If so, the leaking fluid could be slightly more innocent than hydraulic fluid or oil.
zipsy From UK - England, joined Jul 2010, 37 posts, RR: 0 Reply 26, posted (9 months 3 weeks 18 hours ago) and read 4502 times:
Quoting soon7x7 (Reply 25):
Does the Embraer drain mast also vent lavatory grey water? If so, the leaking fluid could be slightly more innocent than hydraulic fluid or oil.
The Embraer jets do have 2 grey water drain masts but this fin like mast is different.It did smell like burned oil and also a horrible fishy smell was present.It was pretty disgusting and made me feel sick.
pilotpip From United States of America, joined Sep 2003, 3082 posts, RR: 12 Reply 27, posted (9 months 2 weeks 6 days 23 hours ago) and read 4321 times:
The Embraer jets do have 2 grey water drain masts but this fin like mast is different.It did smell like burned oil and also a horrible fishy smell was present.It was pretty disgusting and made me feel sick.
That smell is exactly what you think it is. It's very apparent on our older a/c. My theory: the system logic opens the bleed valves too soon after an engine or APU start. It's especially apparent when we start the APU but I've found by selecting the APU bleed off and letting the thing run for a couple minutes the opening the valve the smell is non existient.
As far as the water drain masts, there are 2. One is just forward of the wing root fairing, one is aft. They are usually white and should be labeled "Hot" because they are heated. They drain from the lav and galley sinks.
320tech From Turks and Caicos Islands, joined May 2004, 487 posts, RR: 5 Reply 28, posted (9 months 2 weeks 4 days 18 hours ago) and read 3878 times:
The fin kinda thing on the lower aft fuselage is actually the APU fuel drain. I don't recall how it came to be placed there - more bad design by Embraer is my guess - but I think it might be a mod to keep fuel from being ingested into the APU intake.
The aft water drain mast is alongside the fuel drain to the right, near the middle. The forward water drain mast is directly in front of the right air conditioning pack air inlet, which means anything that goes down the forward galley drain goes right through the heat exchanger.
The No 3 hydraulics system doesn't use the APU fuel drain. Overflow goes into an ecology bottle in the aft fuselage, behind the pressure dome.
I don't know specifically, but normally strakes such as those on the stretched CRJs are used to improve directional stability on long fuselages when they don't want to increase the size of the tail. Similar strakes can be seen on the Beech 1900D.
The primary function of the design engineer is to make things difficult for the manufacturer and impossible for the AME.
zipsy From UK - England, joined Jul 2010, 37 posts, RR: 0 Reply 30, posted (9 months 2 weeks 3 days 23 hours ago) and read 3669 times:
Quoting 320tech (Reply 28):
That smell is exactly what you think it is. It's very apparent on our older a/c. My theory: the system logic opens the bleed valves too soon after an engine or APU start. It's especially apparent when we start the APU but I've found by selecting the APU bleed off and letting the thing run for a couple minutes the opening the valve the smell is non existient.
That makes sense,the smell occured after engine start.Now why did it smell fishy,like rotten kippers?Never knew burned oil can smell this bad.
zipsy From UK - England, joined Jul 2010, 37 posts, RR: 0 Reply 31, posted (9 months 2 weeks 3 days 23 hours ago) and read 3667 times:
Quoting 320tech (Reply 28):
As far as the water drain masts, there are 2. One is just forward of the wing root fairing, one is aft. They are usually white and should be labeled "Hot" because they are heated. They drain from the lav and galley sinks.
Do these drain masts ever get blocked?I know on older aircraft you get alot of trouble with blocked masts.Are these masts hot on the ground or only in the air?It would be pretty unpleasant for ground staff who may bump into one by accident if they were hot.
320tech From Turks and Caicos Islands, joined May 2004, 487 posts, RR: 5 Reply 33, posted (9 months 1 week 4 days 16 hours ago) and read 3203 times:
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Quoting EMBQA (Reply 29): Incorrect...look at post 6 of the description of what the fin is.
I had a look through the AMM and SRM, and couldn't find a useful reference to the mast. My original statement was based on what I was told by someone who was working on them on a C check line. Looking in AMM 49-17-00, APU Drains, it states that the APU combustor has an overboard drain for fuel in case of an aborted start. It doesn't really show where the drain goes, though. Other APU drains empty into the combustor.
The only reference to a No 3 hydraulic system drain that I can find states that shaft seal seepage is drained to an ecology bottle. I don't see anything about a drain for the HSTA.
The next time I'm at work, I will try to have a look in there to confirm that EMBQA is right.
The Embraers EMBQA works on may not have heated water drain masts, but Air Canada's Embraers most definitely have heated masts. They're heated even on the ground, even on nice hot days.
The primary function of the design engineer is to make things difficult for the manufacturer and impossible for the AME.
EMBQA From United States of America, joined Oct 2003, 9286 posts, RR: 13 Reply 34, posted (9 months 1 week 3 days 22 hours ago) and read 3126 times:
Quoting 320tech (Reply 33): The Embraers EMBQA works on may not have heated water drain masts, but Air Canada's Embraers most definitely have heated masts. They're heated even on the ground, even on nice hot days.
He was asking about the drain mast in question... which is not heated. The forward and aft galley water drain are heated
Quoting 320tech (Reply 33): I don't see anything about a drain for the HSTA.
It's the drain for the HSTA Compartment...not solely the HSTA
"It's not the size of the dog in the fight, but the size of the fight in the dog"
zipsy From UK - England, joined Jul 2010, 37 posts, RR: 0 Reply 35, posted (9 months 1 week 1 day 21 hours ago) and read 2997 times:
Quoting EMBQA (Reply 34):
The Embraers EMBQA works on may not have heated water drain masts, but Air Canada's Embraers most definitely have heated masts. They're heated even on the ground, even on nice hot days.
Why are they heated on the ground?It's only up in the air where they need to be heated.The ground crew better watch out then!
loggat From United States of America, joined Feb 2000, 660 posts, RR: 0 Reply 36, posted (9 months 6 days ago) and read 2777 times:
Quoting zipsy (Reply 35): Why are they heated on the ground?
Gray water drains through these masts at all times in the air and on the ground. There is no gray water storage. The front galley and lavatory sinks drain out of the forward mast. The rear galley and lavatory sinks drain out of the rear mast. Edmonton (CYEG) in the winter would be a good reason to heat them on the ground.
There are 3 types of people in this world, those that can count, and those that can't.
Larshjort From Denmark, joined Dec 2007, 1216 posts, RR: 0 Reply 37, posted (9 months 5 days 23 hours ago) and read 2757 times:
Quoting zipsy (Reply 35): Why are they heated on the ground?It's only up in the air where they need to be heated.The ground crew better watch out then!
1. As round crew I would keep away from them at any tme, heated or not. You never know when somebody is going to pour coffee down the drain.
2. They are labeled HOT, and they are not placed where ou would normally place your hand. If you bump into them with your head then the heat isn't biggest problem.
zipsy From UK - England, joined Jul 2010, 37 posts, RR: 0 Reply 41, posted (9 months 4 days 8 hours ago) and read 2532 times:
Talking about grey water drain masts,how do you guys unblock them if they get clogged?Also interested to know which aircraft (Boeing,Airbus,Embraer) is the worst offender when clogging up?Any pics would be great.
Almost 9 years working on Ejets and I've never seen a clogged drain. There really is noting that can clog it as the sink drain will not allow anything big down it...and its a 1" hose.
"It's not the size of the dog in the fight, but the size of the fight in the dog"
HAWK21M From India, joined Jan 2001, 31201 posts, RR: 58 Reply 43, posted (9 months 3 days 9 hours ago) and read 2411 times:
Quoting zipsy (Reply 41): Talking about grey water drain masts,how do you guys unblock them if they get clogged?Also interested to know which aircraft (Boeing,Airbus,Embraer) is the worst offender when clogging up?Any pics would be great.
On the B737.....We use the Hot water method,followed by reverse blowing of Nitrogen ie drain to the sink.At that time the problem was the FAs used to drain the Tea/coffee down the sink.this was later stopped.
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