I suspect this feature/hole has something to do with the engine's fire bottles.
My questions are....... What is being indicated?
Is it that the fire extinguisher is fully charged?
Is it that the extinguisher has been used and thus needs servicing?
Is this object a pre flight "walk around" check for the pilots or strickly used by maintenance personnel?
What does this round object/hole do? Does it change colour? Does an object stick out of it when it's indicating?
Finally, do other jet airliner's engine's have these Extinguisher Indicators on the outside of their cowlings?
Avt007 From Canada, joined Jul 2000, 2132 posts, RR: 5 Reply 1, posted (9 years 12 months 2 days 11 hours ago) and read 3011 times:
Pretty much every aircraft will have these, though the location varies. Some are on the fuselage, some on the cowling. There are nromally two for each fire bottle. This picute only shows one, but the idea is that when the bottle is discharged, some of the pressure is sent down a second line to the indicator, which is a coloured metal disc. At the end of the line is a springloaded piston wi tha pin on the end of it. The pressure moves the piston, and the pin pushes out the disc, which is just clipped in place. The disc falss out, indicating a discharge. It is a quick thing to glance at and see if the bottle has been blown. Whether the pilots look at it is a matter for the operators SOP. When there are two indicators, the red one means the bottle blew because the internal pressure rose too high, and was vented overboard before the bottle exploded. The yellow one is for an intentional discharge by the crew.
Mr Spaceman From Canada, joined Mar 2001, 2786 posts, RR: 9 Reply 2, posted (9 years 12 months 2 days 11 hours ago) and read 3012 times:
Wow, that was a quick reply and very much appreciated.
Thank You, sir for the detailed info on what that object is for and how it works. It's pretty neat to me to learn about the smaller less obvious gadgets that can be found on an airliner's body and engines.
Avt007 From Canada, joined Jul 2000, 2132 posts, RR: 5 Reply 4, posted (9 years 12 months 2 days 9 hours ago) and read 2959 times:
Perhaps "intentional" is a bad word. The yellow disc is only blown out if the bottle is discharged by the squib, through the cockpit switch. More than one bottle has been blown unintentionally.
Spaceman- you're welcome! I enjoy showing off my knowledge as much as the next guy!
Musang From United Kingdom, joined Apr 2001, 796 posts, RR: 7 Reply 6, posted (9 years 12 months 23 hours ago) and read 2848 times:
On the RJ and, I believe, the 146 because in many ways they're identical, the green disc blows out if there is a thermal discharge of the fire bottle, i.e. its an over-pressure relief system to vent the extinguisher if for some reason it gets too hot (and therefore its internal pressure gets dangerous).
There are two extinguisher bottles per engine, located in the front of the cowling. If the green disc is blown out, the inside of the "bowl" shaped end of the pipe is revealed, which is red. One each side of each pod. On the preflight, a simple task to check each of the eight green discs.
Similarly, the aircraft has an oxygen bottle discharge disc on the lower right side just forward of the baggage hold, with a white disc. If that blows, according to the manual, streamers are deployed, to attract attention. Never seen it, not even a picture, so don't know how long the streamers are or what colour.
VC-10 From United Kingdom, joined Oct 1999, 3691 posts, RR: 35 Reply 9, posted (9 years 12 months 19 hours ago) and read 2837 times:
The 727 has the yellow disc
Funny you should say that because I was thinking about it after I posed the question and thought I could remember yellow disc's on 707 # 2 & 3 sailboat fairings. As it has been 22 years since I last worked on one I couldn't remember. So if the 72 has them the 70 must have had them.
Real airplanes have a light in the cockpit that tells you the bottle is empty. - Couldn't agree more
Cdfmxtech From United States of America, joined Jul 2000, 1338 posts, RR: 28 Reply 10, posted (9 years 12 months 19 hours ago) and read 2830 times:
Classic 737 APUs have 2 disks on the right side of the tail area to indicate either a normal discharge (yellow), or a thermal discharge (red). Either way, there is an APU Bottle discharge light in the flightdeck. Missing indicators indicate the above mentioned conditions.
Avt007 From Canada, joined Jul 2000, 2132 posts, RR: 5 Reply 11, posted (9 years 12 months 12 hours ago) and read 2812 times:
Lights are good too, and most planes I`ve worked have them, but don`t think thats foolproof too. Always have a backup! Discs don`t need power, they can`t burn out like lamps, they are basic and fairly foolproof, yet I have seen the odd disc fall out for no reason, except maybe they weren`t installed properly.
UAL Bagsmasher From United States of America, joined Sep 1999, 2134 posts, RR: 10 Reply 15, posted (9 years 11 months 4 weeks 1 day 19 hours ago) and read 2769 times:
LOL I just had a practical on this yesterday. I had to inspect the fire supression system on our T-39A. Bottle pressures, lines, and disks. Disks were missing and the bottles were low. Gee go figure...at a school and all....