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    Re: Question for pilots.
    From: Gary LaPook
    Date: 2014 Mar 18, 09:32 -0700
    I received an email asking about the ELT, here is my reply.

    They only activate automatically after sustaining a lot of G's indicating to the device that the plane has crashed.

    Federal law requires a 121.5 mhz ELT be installed in general aviation aircraft only, not required for airliners. 
    This frequency is no longer monitored by satellites since 2009 so even if one were installed in the plane and manually activated there is no reason to believe that it would have been heard.

    The newer, 406 mhz, beacons, which are satellite monitored, are not required in US made or operated aircraft, even in general aviation planes. These newer ones are permitted to be installed but are not required, are expensive, so nobody is installing them.

    Certification of transport category aircraft is governed by FAR part 25, (14 CFR part 25,) and this does not require ELTs for the aircraft itself.


    Nor does FAR part 121 which governs operations by air carriers.



    One is required to be attached to ONE life raft if rafts are installed but these do not operate automatically, the raft must be deployed and the ELT must then be activated manually.

    Safety Equipment
    §25.1411   General.
    (e) Long-range signaling device. The stowage provisions for the long-range signaling device required by §25.1415 must be near an exit available during an unplanned ditching.
    §25.1415   Ditching equipment.
    (a) Ditching equipment used in airplanes to be certificated for ditching under §25.801, and required by the operating rules of this chapter, must meet the requirements of this section.
    (b) Each liferaft and each life preserver must be approved. In addition—
    (1) Unless excess rafts of enough capacity are provided, the buoyancy and seating capacity beyond the rated capacity of the rafts must accommodate all occupants of the airplane in the event of a loss of one raft of the largest rated capacity; and
    (2) Each raft must have a trailing line, and must have a static line designed to hold the raft near the airplane but to release it if the airplane becomes totally submerged.
    (c) Approved survival equipment must be attached to each liferaft.
    (d) There must be an approved survival type emergency locator transmitter for use in one life raft.


    Some have speculated that the pilots could have turned off the emergency oxygen equipment for the passengers but this is not true. Federal Aviation Regulations require that they be completely automatic. The pilots can deploy them but they can't disable the automatic deployment of the masks when the cabin altitude reaches 15,000 feet.

    §25.1447   Equipment standards for oxygen dispensing units.
    If oxygen dispensing units are installed, the following apply:
    (c) If certification for operation above 25,000 feet is requested, there must be oxygen dispensing equipment meeting the following requirements:
    (1) There must be an oxygen dispensing unit connected to oxygen supply terminals immediately available to each occupant, wherever seated, and at least two oxygen dispensing units connected to oxygen terminals in each lavatory. The total number of dispensing units and outlets in the cabin must exceed the number of seats by at least 10 percent. The extra units must be as uniformly distributed throughout the cabin as practicable. If certification for operation above 30,000 feet is requested, the dispensing units providing the required oxygen flow must be automatically presented to the occupants before the cabin pressure altitude exceeds 15,000 feet. The crew must be provided with a manual means of making the dispensing units immediately available in the event of failure of the automatic system.


    Here is a link to the training manual for the B-777, I could find nothing about an ELT but you are welcome to look.


    From: Paul Niquette <paul{at}niquette.com>
    To: Gary J. LaPook <garylapook---.net>
    Sent: Tuesday, March 18, 2014 3:16 AM
    Subject: ELT?
    What about this?
    I am puzzled why this system has not been mentioned at all so far.

    From: Gary LaPook <garylapook---.net>
    To: garylapook---.net
    Sent: Monday, March 17, 2014 9:46 PM
    Subject: [NavList] Re: Question for pilots.

    Radar is limited to the radar horizon, about 1.44 times the square root of the height of the antenna plus 1.44 times the height of the plane.  From 35,000 feet the radar horizon is 230 nautical miles away. The radar detection range might be further limited by the power output of the radar transmitter based on the fourth power of the range, from the standard radar range formula. If the lane descended to 5,000 feet then the radar horizon was limited to about 90 NM. When I flew the ocean, separation of planes was based on HF position reports given by the pilots in this format:   http://members.home.nl/7seas/radcalc.htm

    The standard format for position reports is:

    "Gander radio this is Cessna November one six two one seven;
    forty west, forty three thirty five north at 2015 ;
    flight level one zero zero;
    Estimating thirty five west, forty one twenty north at 2230 ;
    Mike next;

    This is the same format over the U.S. if radar is inop.

    The time (Zulu of course) of the position is obviously an important element of the report and is the time at the position, not the time of the radio message which might be a bit latter depending on HF propagation conditions.

    As far as I know this is still done but the position reports are now sent over a satellite link instead of HF. 


    From: Lu Abel <luabel{at}ymail.com>
    To: garylapook---.net
    Sent: Monday, March 17, 2014 1:51 PM
    Subject: [NavList] Re: Question for pilots.

    There was a discussion of offshore tracking on one of the (US) national news programs yesterday and when asked about a knowledgeable hijacker disabling satellite tracking (as the MN370 hijackers apparently did with their ground transponder), the aviation expert being interviewed said "unfortunately, there's always a circuit breaker somewhere that someone with sufficient expertise could throw ..." 

    From: Richard B. Langley <lang---.ca>
    To: luabel{at}ymail.com
    Subject: [NavList] Re: Question for pilots.

    In the future, we might not have to rely on radar. NAV CANADA has entered into a joint venture with Iridium Communications, called Aireon, which will expand air traffic surveillance to the entire planet by installing ADS-B receivers on Low Earth Orbit (LEO) satellites. The plan is to use the Iridium NEXT satellites.
    I guess such a system could also be turned off on an aircraft unless it is made tamper-proof. But it would likely have a circuit breaker somewhere.

    View and reply to this message: http://fer3.com/arc/m2.aspx?i=127243

    View and reply to this message: http://fer3.com/arc/m2.aspx?i=127250

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