Bio15 From Colombia, joined Mar 2001, 1089 posts, RR: 7 Posted (11 years 4 months 3 weeks 2 days 22 hours ago) and read 2607 times:
Hi everyone. I came across these two pictures below, and some questions came to my mind:
1) On the SELCAL section of the overhead panel I see both L & R (left & right I assume) for VHF and for HF radio frequencies. Where are the VHF and HF radios located? Do the frequencies seen above (13.297 and 11.396) have anything to do with the SELCAL unit?
Just an additional question, what is the FLT INT button for? (also on the SELCAL quadrant)
2) Just to the right of the GPWS warning override buttons there's a vertical row of switches, and each one has two black bars (annunciators probably). What are these for? I only saw these switches on the American Airlines 767.
Cdfmxtech From United States of America, joined Jul 2000, 1338 posts, RR: 27
Reply 1, posted (11 years 4 months 3 weeks 2 days 20 hours ago) and read 2557 times:
>On the SELCAL section of the overhead panel I see both L & R (left & right I assume) for VHF and for HF radio frequencies. Where are the VHF and HF radios located? <
The HF control panels are located on the overhead panel. The panels are the ones with the frequencies shown. The left panel is above the Bat Switch/Stby Pwr panel and the right is above the Pilot Call Panel (or what u call the SELCAL ctrl panel).
>Do the frequencies seen above (13.297 and 11.396) have anything to do with the SELCAL unit?<
See above reply. Those freqs are HF freqs.
SELCAL only monitors VHF and HF. There is no control for it in the flightdeck.
>Just to the right of the GPWS warning override buttons there's a vertical row of switches, and each one has two black bars (annunciators probably). What are these for? I only saw these switches on the American Airlines 767.<
Don't know. We don't have that panel on our aircraft.
AAR90 From United States of America, joined Jan 2000, 3451 posts, RR: 47
Reply 2, posted (11 years 4 months 3 weeks 2 days 18 hours ago) and read 2543 times:
#2 is AA's 757/767 Mechanical Checklist. No matter what else you may do wrong, if you complete these checklists the plane will safely takeoff, fly and land. ALL AA aircraft have some form of Mechanical Checklist installed and every AA Captain I've ever flown with (myself included) glances at the Mechanical Checklist prior to every takeoff and every landing.
*NO CARRIER* -- A Naval Aviator's worst nightmare!
ERFly From United States of America, joined Aug 2002, 164 posts, RR: 0
Reply 3, posted (11 years 4 months 3 weeks 2 days 14 hours ago) and read 2513 times:
The FLT INT button is the Flight Intercom switch...Basically what that does is allows the pilots to tap into the cabin crew interphone system. If an F/A calls the flight deck, they can either pick up the handset on the center pedestal or press that button, and the INT button on the comm panel and talk through the hand mike and speakers or their headset.
Dc10hound From United States of America, joined Dec 2000, 463 posts, RR: 5
Reply 5, posted (11 years 4 months 3 weeks 2 days 6 hours ago) and read 2472 times:
I don't fully understand the difference of SELCAL using VHF and ATC usual VHF communications. That means you can talk to ATC with SELCAL?
SELCAL is there to let you know that "mother" is calling. When the SELCAL chime is heard, and the SELCAL light illuminates, it is letting you know that your company is trying to raise you on the respective radio.
It, along with ACARS, is your electronic dog leash.
Think of it as a pager that uses HF or VHF.
"Eagles soar. But weasels never get sucked into jet intakes.."
Avioniker From United States of America, joined Dec 2001, 1109 posts, RR: 11
Reply 6, posted (11 years 4 months 3 weeks 2 days 5 hours ago) and read 2467 times:
Actually the Flt Int is for flight deck crew communication and there is normally a jack for ground crew communication located in the external power panel.
Service Interphone and Cabin Interphone are for communication throughout the aircraft external to the flight deck and there is a separate button so that system may be used to communicate with the flight deck for maintenance from various remote parts of the plane.
SelCal stands for Selective Call. Each aircraft is assigned a unique four letter code which represents a set of two tone harmonics. When the crew is monitoring a "noisy" frequency the SelCal allows them to turn the volume down thus reducing flight deck distractions. When a station or Dispatch wants to communicate with that specific aircraft they transmit the tones which that aircraft's SelCal is set to monitor. This comes through in the flight deck as a "doorbell" sound via the aural warning system and alerts the crew they need to turn up the radio the call is coming in on. They can tell which radio to turn up by looking at a panel which will have an annunciator lit for that radio. The SelCal resets as soon as the crew transmits on that radio and is ready to respond to a new call.
If the plane has ACARS it may also be tied to a SelCal channel and it will automatically respond and reset the SelCal. The doorbell chimes alert the crew to the incomming ACARS message.
The older systems used vibrating reeds and had one or two channels so the reilability wasn't too great and you can only have one radio per channel.
Current systems use tuned tank circuits and have five channels (more may be added) so that the company may couple all of the radios (HF and VHF) and ACARS to the system.
For visual indicating and alerting there may be a dedicated panel with annunciator lights or the "Call lights" may be integrated into the radio transmitter (Mic) button on the audio control panels.
The advances in avionics are getting closer to magic every day.
Pretty soon the "one man - one dog" cockpit will be a reality.
One may educate the ignorance from the unknowing but stupid is forever. Boswell; ca: 1533
ERFly From United States of America, joined Aug 2002, 164 posts, RR: 0
Reply 7, posted (11 years 4 months 3 weeks 2 days 2 hours ago) and read 2445 times:
The intercom to talk with the ground crew is tied into the Flight Intercom on the comm panel. The one on the overhead is to tie into the service intercom. The GND CALL light illuminated when the ground is calling upstairs. Then they just select the switch on the comm panel.
Bio15 From Colombia, joined Mar 2001, 1089 posts, RR: 7
Reply 8, posted (11 years 4 months 3 weeks 16 hours ago) and read 2372 times:
I appreciate all of your responses. I do understand the general purpose of SELCAL and how it is used.
My questions were rather oriented toward the more specific silly details (sorry about that). For example, can the dispatcher contact the aircraft on any HF or VHF frequency if the pilots don't have it tuned on their overhead or pedestal radios?
How many VHF radios does the aircraft have on the pedestal? 2 for SELCAL 2 for ATC?
All refered to the 767.
HAL From United States of America, joined Jan 2002, 2529 posts, RR: 53
Reply 9, posted (11 years 4 months 2 weeks 6 days 14 hours ago) and read 2341 times:
Regarding SELCAL, The buttons you see are the lights that go on in addition to hearing the chime.
In simple terms, there aren't separate radios for SELCAL and comm. The SELCAL signal comes through your main comm radios - HF and VHF. You have to have the proper frequency tuned in (either HF or VHF) for ATC or company to chime you on SELCAL. No, the company can't tune your radio for you. For example all aircraft flying over water monitor AIRINC on HF for giving position reports and getting SELCAL messages. AIRINC isn't ATC, but rather a radio company that acts as a clearing-house for information between us and ATC. When ATC wants to give us a message, they call AIRINC, who then gives us a SELCAL on the HF frequency they previously told us to monitor. When they call us, a chime goes off, and the light on the appropriate overhead button illuminates, telling us which radio they're calling us on. We push the button to extinguish the light (or on some planes, keying the microphone also extinguishes the light) and talk to whoever is calling us. Over land, if ACARS is inop, we keep one of the VHF radios tuned to the appropriate AIRINC frequency for wherever we are, and the SELCAL signal comes over that radio. But if ACARS is operational, we don't have to keep one of the VHF radios listening to AIRINC. Our 767's all have three VHF radios - one dedicated to ACARS, and two for talking to ATC. If the ACARS is inop, that radio would be tuned to the AIRINC frequency (as described above) to listen for the SELCAL chime.
In the photograph in the first post, it appears the plane has only two VHF radios, along with the two HF radios - hence only two buttons on the SELCAL panel.
In our newest planes, those button-lights for SELCAL have been removed. When we get a SELCAL, a message appears on the EICAS screen, and the appropriate switch on our audio panel lights up with a "call" light above the volume dial for that radio. The only button-lights left on the overhead panel are the cabin call buttons from the F/A's panels.
Hope this helps.
One smooth landing is skill. Two in a row is luck. Three in a row and someone is lying.