ED Decision 2018/007/R
(a) Accessibility. Required safety equipment to be used by the crew in an emergency must be readily accessible.
(b) Stowage provisions. Stowage provisions for required safety equipment must be furnished and must:
(1) be arranged so that the equipment is directly accessible and its location is obvious; and
(2) protect the safety equipment from inadvertent damage.
[Amdt No: 27/5]
AMC 27.1411 Safety equipment – General
ED Decision 2018/007/R
This AMC replaces FAA AC 27.1411.
(a) Explanation
CS-27 Amendment 5 introduced changes related to ditching and associated equipment. In particular, it defined a standard set of terminology, it simplified CS 27.1411 in line with it being a general certification specification for safety equipment, reorganised CS 27.1415 specifically for ditching equipment, and created a new CS 27.1470 on the installation and carriage of emergency locator transmitters (ELTs). All requirements relating to life raft installations are now co-located in CS 27.1415.
(1) The safety equipment should be accessible and appropriately stowed, and it should be ensured that:
(i) locations for stowage of all required safety equipment have been provided;
(ii) safety equipment is readily accessible to both crew members and passengers, as appropriate, during any reasonably probable emergency situation;
(iii) stowage locations for all required safety equipment will adequately protect such equipment from inadvertent damage during normal operations; and
(iv) safety equipment stowage provisions will protect the equipment from damage during emergency landings when subjected to the inertia loads specified in CS 27.561.
(b) Procedures
(1) A cockpit evaluation should be conducted to demonstrate that all required emergency equipment to be used by the flight crew will be readily accessible during any probable emergency situation. This evaluation should include, for example, emergency flotation equipment actuation devices, remote life raft releases, door jettison handles, handheld fire extinguishers, and protective breathing equipment.
(2) Stowage provisions for safety equipment shown to be compatible with the vehicle configuration presented for certification should be provided and identified so that:
(i) equipment is readily accessible regardless of the operational configuration;
(ii) stowed equipment is free from inadvertent damage from passengers and handling; and
(iii) stowed equipment is adequately restrained to withstand the inertia forces specified in CS 27.561(b)(3) without sustaining damage.
[Amdt No: 27/5]
ED Decision 2003/15/RM
Each safety belt must be equipped with a metal to metal latching device.
ED Decision 2018/007/R
If certification with ditching provisions or emergency flotation provisions is requested by the applicant, the additional safety equipment required by any applicable operating rule must meet the requirements of this CS.
(a) All equipment must be approved.
(b) Life rafts.
(1) Required life raft(s) must be remotely deployable for use in an emergency. Remote controls capable of deploying the life raft(s) must be located within easy reach of the flight crew, occupants of the passenger cabin and survivors in the water, with the rotorcraft in the upright floating or capsized position. It must be substantiated that life rafts sufficient to accommodate all rotorcraft occupants, without exceeding the rated capacity of any life raft, can be reliably deployed with the rotorcraft in any reasonably foreseeable floating attitude, including capsized, and in the sea conditions chosen for showing compliance with CS 27.801(e).
(2) Each life raft must be attached to the rotorcraft by a short retaining line to keep it alongside the rotorcraft and a long retaining line designed to keep it attached to the rotorcraft. Both retaining lines must be weak enough to break before submerging the empty life raft to which they are attached. The long retaining line must be of sufficient length that a drifting life raft will not be drawn towards any part of the rotorcraft that would pose a danger to the life raft itself or the persons on board.
(3) Each life raft must be substantiated as suitable for use in all sea conditions covered by the certification with ditching or emergency flotation provisions.
(c) Life preservers.
If the applicable operating rule allows for life preservers not to be worn at all times, stowage provisions must be provided that accommodate one life preserver for each occupant for which certification with ditching or emergency flotation provisions.
[Amdt No: 27/5]
AMC 27.1415 Ditching equipment
ED Decision 2018/007/R
This AMC replaces FAA AC 27.1415.
(a) Explanation
(1) Additional safety equipment is not required for all rotorcraft overwater operations. However, if such equipment is required by the applicable operating rule, the equipment supplied should satisfy this AMC.
NOTE: Although the term ‘ditching’ is most commonly associated with the design standards related to CS 27.801 (ditching approval), a rotorcraft equipped to the less demanding requirements of CS 27.802 (emergency flotation approval), when performing an emergency landing on to water, would nevertheless be commonly described as carrying out the process of ditching. The term ‘ditching equipment’ is therefore to be considered to apply to any safety equipment required by operational rule for operation over water.
It is a frequent practice for the rotorcraft manufacturer to provide the substantiation for only those portions of the ditching requirements relating to rotorcraft flotation and emergency exits. Completion of the ditching certification to include the safety equipment installation and stowage provisions is then left to the affected operator to arrange via a modifier so that those aspects can best be adopted to the selected cabin interior. In such cases, the ‘Limitations’ section of the rotorcraft flight manual (RFM) should identify the substantiations yet to be provided in order to justify the full certification with ditching provisions. The modifier performing these final installations is then concerned directly with the details of this AMC. Any issues arising from aspects of the basic rotorcraft flotation and emergency exits certification that are not compatible with the modifier’s proposed safety equipment provisions should be resolved between the type certificate (TC) holder and the modifier prior to the certifying authority’s certification with ditching provisions (see AMC 27.801(b)(12) and AMC 27.1415(a)(2)(ii)).
(2) Compliance with the requirements of CS 27.801 for rotorcraft ditching requires compliance with the safety equipment stowage requirements and ditching equipment requirements of CS 27.1411 and CS 27.1415, respectively.
(i) Ditching equipment, installed to complete ditching certification, or required by the applicable operating rule, should be compatible with the basic rotorcraft configuration presented for ditching certification. It is satisfactory if the operating equipment is not incorporated at the time of the original rotorcraft type certification provided that suitable information is included in the ‘Limitations’ section of the rotorcraft flight manual (RFM) to identify the extent of ditching certification not yet completed.
(ii) When ditching equipment is being installed by a person other than the applicant who provided the rotorcraft flotation system and emergency exits, special care should be taken to avoid degrading the functioning of those items, and to make the ditching equipment compatible with them (see AMC 27.801(b)(12)).
(b) Procedures
All ditching equipment, including life rafts, life preservers, immersion suits, emergency breathing systems etc., should be of an approved type. Life rafts should be chosen to be suitable for use in all sea conditions covered by the certification with ditching provisions.
(1) Life rafts
(i) Life rafts are rated during their approval according to the number of people that can be carried under normal conditions and the number that can be accommodated in an overload condition. Only the normal rating may be used in relation to the number of occupants permitted to fly in the rotorcraft.
(ii) Where two life rafts are installed, they should deploy on opposite sides of the rotorcraft in order to minimise the probability that both will be damaged during water entry/impact, and to provide the maximum likelihood that at least one raft will be useable in any wind condition.
(iii) Successful deployment of life raft installations should be demonstrated in representative orientations. Testing should be performed, including underwater deployment, if applicable, to demonstrate that life rafts sufficient to accommodate all rotorcraft occupants, without exceeding the rated capacity of any life raft, will deploy reliably with the rotorcraft in any reasonably foreseeable floating attitude, including capsized. It should also be substantiated that reliable deployment will not be compromised by inertial effects from the rolling/pitching/heaving of the rotorcraft in the sea conditions chosen for the demonstration of compliance with the flotation/trim requirements of CS 27.801(e), or by intermittent submerging of the stowed raft location (if applicable) and the effects of wind. This substantiation should also consider all reasonably foreseeable rotorcraft floating attitudes, including capsized. Reasonably foreseeable floating attitudes are considered to be, as a minimum, upright, with and without loss of the critical emergency flotation system (EFS) compartment, and capsized, also with and without loss of the critical EFS compartment. Consideration should also be given towards maximising, where practicable, the likelihood of life raft deployment for other cases of EFS damage.
(iv) Rotorcraft fuselage attachments for the life raft retaining lines should be provided.
(A) Each life raft must be equipped with two retaining lines to be used for securing the life raft to the rotorcraft. The short retaining line should be of such a length as to hold the raft at a point next to an upright floating rotorcraft such that the occupants can enter the life raft directly without entering the water. If the design of the rotorcraft is such that the flight crew cannot enter the passenger cabin, it is acceptable that they would need to take a more indirect route when boarding the life raft. After life raft boarding is completed, the short retaining line may be cut and the life raft then remain attached to the rotorcraft by means of the long retaining line.
(B) Attachments on the rotorcraft for the retaining lines should not be susceptible to damage when the rotorcraft is subjected to the maximum water entry loads established by CS 27.563.
(C) Attachments on the rotorcraft for the retaining lines should be structurally adequate to restrain a fully loaded life raft.
(D) Life rafts should be attached to the rotorcraft by the required retaining lines after deployment without further action from the crew or passengers.
(E) It should be verified that the length of the long retaining line will not result in the life raft taking up a position which could create a potential puncture risk or hazard to the occupants, such as directly under the tail boom, tail rotor or main rotor disc.
(v) Life raft stowage provisions should be sufficient to accommodate rafts for the maximum number of occupants for which certification for ditching is requested by the applicant.
(vi) Life raft activation
The following should be provided for each life raft:
(A) primary activation: manual activation control(s), readily accessible to each pilot on the flight deck whilst seated;
(B) secondary activation: manual activation control(s) accessible from the passenger cabin; if any control is located within the cabin, it should be protected from inadvertent operation; and
(C) tertiary activation: manual activation control(s) accessible to a person in the water, with the rotorcraft in all foreseeable floating attitudes, including capsized.
It is acceptable for two or more of the above functions to be incorporated into one control.
Automatic life raft activation is not prohibited (e.g. it could be triggered by water immersion). However, if such a capability is provided, it should be in addition to the above manual activation controls, not instead of them, and issues such as inadvertent deployment in flight and the potential for damage from turning rotors during deployment on the water should be mitigated.
Placards should be installed, of appropriate size, number and location, to highlight the location of each of the above life raft activation controls. All reasonably foreseeable rotorcraft floating attitudes should be considered.
(vii) Protection of life rafts from damage
Service experience has shown that following deployment, life rafts are susceptible to damage while in the water adjacent to the rotorcraft due to projections on the exterior of the rotorcraft such as antennas, overboard vents, unprotected split-pin tails, guttering, etc. and any projections sharper than a three-dimensional right angled corner. Projections likely to cause damage to a deployed life raft should be avoided by design, or suitably protected to minimise the likelihood of their causing damage to a deployed life raft. In general, projections on the exterior surface of the helicopter, that are located in a zone delineated by boundaries that are 1.22 m (4 ft) above and 0.61 m (2 ft) below the established static water line should be assessed. Relevant maintenance information should also provide procedures for maintaining such protection for rotorcraft equipped with life rafts. Furthermore, due account should be taken of the likely damage that may occur (e.g. disintegration of carbon-fibre panels or structure) during water entry and its potential hazard to deployed life rafts.
(2) Life preservers.
No provision for the stowage of life preservers is necessary if the applicable operating rule mandates the need for constant-wear life preservers.
(3) Emergency signalling equipment.
Emergency signalling equipment required by the applicable operating rule should be free from hazards in its operation, and operable using either bare or gloved hands. Required signalling equipment should be easily accessible to the passengers or crew and located near an emergency exit or included in the survival equipment attached to the life rafts.
[Amdt No: 27/5]
ED Decision 2003/15/RM
(a) To obtain certification for flight into icing conditions, compliance with this paragraph must be shown.
(b) It must be demonstrated that the rotorcraft can be safely operated in the continuous maximum and intermittent maximum icing conditions determined under appendix C of CS-29 within the rotorcraft altitude envelope. An analysis must be performed to establish, on the basis of the rotorcraft’s operational needs, the adequacy of the ice protection system for the various components of the rotorcraft.
(c) In addition to the analysis and physical evaluation prescribed in sub-paragraph (b), the effectiveness of the ice protection system and its components must be shown by flight tests of the rotorcraft or its components in measured atmospheric icing conditions and by one or more of the following tests as found necessary to determine the adequacy of the ice protection system:
(1) Laboratory dry air or simulated icing tests, or a combination of both, of the components or models of the components.
(2) Flight dry air tests of the ice protection system as a whole, or its individual components.
(3) Flight tests of the rotorcraft or its components in measured simulated icing conditions.
(d) The ice protection provisions of this paragraph are considered to be applicable primarily to the airframe. Powerplant installation requirements are contained in Subpart E of this CS-27.
(e) A means must be identified or provided for determining the formation of ice on critical parts of the rotorcraft. Unless otherwise restricted, the means must be available for night-time as well as daytime operation. The rotorcraft flight manual must describe the means of determining ice formation and must contain information necessary for safe operation of the rotorcraft in icing conditions.
ED Decision 2003/15/RM
(a) Design. Each hydraulic system and its elements must withstand, without yielding, any structural loads expected in addition to hydraulic loads.
(b) Tests. Each system must be substantiated by proof pressure tests. When proof tested, no part of any system may fail, malfunction, or experience a permanent set. The proof load of each system must at least 1.5 times the maximum operating pressure of that system.
(c) Accumulators. No hydraulic accumulator or pressurised reservoir may be installed on the engine side of any firewall unless it is an integral part of an engine.
CS 27.1457 Cockpit voice recorders
ED Decision 2003/15/RM
(a) Each cockpit voice recorder required by the applicable operating rules must be approved, and must be installed so that it will record the following:
(1) Voice communications transmitted from or received in the rotorcraft by radio.
(2) Voice communications of flight-crew members on the flight deck.
(3) Voice communications of flight-crew members on the flight deck, using the rotorcraft’s interphone system.
(4) Voice or audio signals identifying navigation or approach aids introduced into a headset or speaker.
(5) Voice communications of flight-crew members using the passenger loudspeaker system, if there is such a system, and if the fourth channel is available in accordance with the requirements of sub-paragraph (c)(4)(ii).
(b) The recording requirements of subparagraph (a)(2) may be met:
(1) By installing a cockpit-mounted area microphone located in the best position for recording voice communications originating at the first and second pilot stations and voice communications of other crew members on the flight deck when directed to those stations; or
(2) By installing a continually energised or voice-activated lip microphone at the first and second pilot stations. The microphone specified in this paragraph must be so located and if necessary, the preamplifiers and filters of the recorder must be adjusted or supplemented so that the recorded communications are intelligible when recorded under flight cockpit noise conditions and played back. The level of intelligibility must be approved by the Agency. Repeated aural or visual playback of the record may be used in evaluating intelligibility.
(c) Each cockpit voice recorder must be installed so that the part of the communication or audio signals specified in sub-paragraph (a) obtained from each of the following sources is recorded on a separate channel:
(1) For the first channel, from each microphone, headset, or speaker used at the first pilot station.
(2) For the second channel, from each microphone, headset, or speaker used at the second pilot station.
(3) For the third channel, from the cockpit-mounted area microphone, or the continually energised or voice-activated lip microphone at the first and second pilot stations.
(4) For the fourth channel, from:
(i) Each microphone, headset, or speaker used at the stations for the third and fourth crew members; or
(ii) If the stations specified in sub-paragraph (c)(4)(i) are not required or if the signal at such a station is picked up by another channel, each microphone on the flight deck that is used with the passenger loud-speaker system if its signals are not picked up by another channel.
(iii) Each microphone on the flight deck that is used with the rotorcraft’s loudspeaker system if its signals are not picked up by another channel.
(d) Each cockpit voice recorder must be installed so that:
(1) It receives its electric power from the bus that provides the maximum reliability for operation of the cockpit voice recorder without jeopardising service to essential or emergency loads;
(2) There is an automatic means to simultaneously stop the recorder and prevent each erasure feature from functioning, within 10 minutes after crash impact; and
(3) There is an aural or visual means for pre-flight checking of the recorder for proper operation.
(e) The record container must be located and mounted to minimise the probability of rupture of the container as a result of crash impact and consequent heat damage to the record from fire.
(f) If the cockpit voice recorder has a bulk erasure device, the installation must be designed to minimise the probability of inadvertent operation and actuation of the device during crash impact.
(g) Each recorder container must be either bright orange or bright yellow.
CS 27.1458 Lightweight flight recorder
ED Decision 2023/001/R
(a) Each lightweight flight recorder required by the applicable operating rules must be approved and must be installed so that:
(1) there is an aural or visual means for pre-flight checking of the recorder for proper recording of data in the storage medium; and
(2) it automatically starts recording prior to the rotorcraft being capable of moving under its own power and automatically stops recording after the rotorcraft is no longer capable of moving under its own power.
(b) The container of the recording medium must be located and mounted so as to minimise the probability of the container rupturing or the recording medium being destroyed as a result of impact with the Earth’s surface and subsequent heat damage caused by a post-impact fire, to an acceptable level.
(c) The recording medium container of the lightweight flight recorder in sub-paragraph (a) must:
(1) have a high proportion of its outer surface area coloured in bright orange; and
(2) have dimensions that are adequate for visually locating it on an accident scene.
(d) Each flight parameter to be recorded as required by the applicable operating rules must be recorded as digital data or by means of images.
(e) If the lightweight flight recorder in sub-paragraph (a) records a flight parameter as required by the applicable operating rules by means of images, the image source must be installed to provide images with a quality sufficient for reading the values of this flight parameter during all phases of the flight.
(f) If the lightweight flight recorder in sub-paragraph (a) records images or audio of the flight crew area:
(1) an ‘erase function’ must be provided, which can be operated by the commander and which modifies image and audio recordings made before the operation of that function, so that those recordings cannot be retrieved using normal replay or copying techniques; and
(2) the probability of inadvertent operation of the erase function and the probability of actuation of that function during crash impact must be minimised.
[Amdt 27/10]
AMC1 27.1458 Lightweight flight recorder
ED Decision 2023/001/R
(a) General
The recorder installed to meet CS 27.1458(a) should be granted an ETSO authorisation in accordance with the following ETSOs or be compliant with at least one of the following standards: ETSO-2C197, ETSO C124b, ETSO C176 (or equivalent standards accepted by EASA).
In demonstrating compliance with CS 27.1458, the applicant should take into account EUROCAE Document ED-155 ‘MOPS for Lightweight Flight Recording Systems’ or EUROCAE Document ED-112 ‘MOPS for Crash Protected Airborne Recorder Systems’ or later revisions of these documents.
‘Flight recorder system’ refers to the lightweight flight recorder and its dedicated equipment. It may include the following items as appropriate to the rotorcraft:
(1) The equipment necessary to:
(i) acquire and process sensor signals;
(ii) store the recorded data in a robust recording medium; and
(iii) when necessary, support dedicated sensors; and
(2) Digital data buses and/or networks providing communications between elements of the system.
The lightweight flight recorder should receive its electric power from the bus that provides the maximum reliability for operation of the recorder without jeopardising supply to load circuits essential for safe operations.
The height, width and depth of the recording medium container of the lightweight flight recorder should be at least 4 cm (1.5 inches).
(b) Installation of the flight recorder system
The flight recorder system should be installed in accordance with the recommendations made in EUROCAE Document ED-155 Section 2-5.3.
The recording medium container should be located and mounted in accordance with the specifications given in EUROCAE Document ED-155 Sections 2-5.4 and 2-5.5.
(c) Evaluation of recordings
The following acceptable means of compliance with CS 27.1458 (a), (d) and (e) is provided to demonstrate that the performance of the installed flight recorder system is acceptable with regard to data recording. Inspections of the recordings that are part of the instructions for continued airworthiness are not within the scope of this paragraph.
(1) A recording made during a flight should be evaluated to confirm that the recording of the data required by Regulation (EU) No 965/2012 is acceptable during all phases of flight where this data should be recorded. In the case of image recordings, refer to Section III-6.4 of ED-155.
(2) The evaluation of the recordings from the flight should include:
(i) checking the correct functioning of the automatic start-and-stop function of the flight recorder system; and
(ii) if the recorder is fitted with a built-in-test feature, checking the absence of faults that may affect the performance of the recorder.
(3) The evaluation of the recordings should be documented in an evaluation report.
(4) The performance of the flight recorder system with regard to data recording should be considered to be acceptable only if sub-paragraphs (c)(1) and (c)(2) of this AMC were satisfactorily addressed.
(5) It is accepted that by implementing emergency procedures (i.e. for smoke/fire isolation) the power supply to the lightweight recorder is cut off.
(d) Image and audio recordings of the flight crew area
If there are no compartments to physically segregate the flight crew from the passengers, the term ‘flight crew area’ in CS 27.1458 should be understood as the area including:
— the flight crew seat(s),
— windshield and windows used by the flight crew to get an external view while seated,
— aircraft instruments and controls, and
— circuit breakers accessible by the flight crew while seated.
(e) Instructions for continued airworthiness (ICA)
When developing the ICA for the flight recorder system, required by CS 27.1529 and Appendix A, the applicant should address all the failures that may affect the performance of the flight recorder system or the quality of the data required to be recorded by Regulation (EU) No 965/2012.
Examples of failures (indicative and non-exhaustive list):
— Loss of the recording function of the lightweight flight recorder;
— Any data required by Regulation (EU) No 965/2012 is missing, or is not correctly recorded;
— Failure of the automatic start-and-stop function.
The ICA should include the procedures to be followed for retrieving the data required to be recorded by the lightweight flight recorder when it is undamaged.
In addition, if the lightweight flight recorder records some required flight parameters as digital data, the ICA should include a document that presents the information necessary to retrieve the raw binary data of these flight parameters from a recording file and to convert this data into engineering units and textual interpretations. If the lightweight flight recorder records some required flight parameters by means of images, the ICA should include a document that presents the information necessary to read the flight parameter values from the recorded images.
[Amdt 27/10]
ED Decision 2003/15/RM
(a) Each flight recorder required by the applicable operating rules must be installed so that:
(1) It is supplied with airspeed, altitude, and directional data obtained from sources that meet the accuracy requirements of CS 27.1323, CS 27.1325, and 27.1327, as applicable;
(2) The vertical acceleration sensor is rigidly attached, and located longitudinally within the approved centre of gravity limits of the rotorcraft;
(3) It receives its electrical power from the bus that provides the maximum reliability for operation of the flight recorder without jeopardising service to essential or emergency loads;
(4) There is an aural or visual means for pre-flight checking of the recorder for proper recording of data in the storage medium;
(5) Except for recorders powered solely by the engine-driven electrical generator system, there is an automatic means to simultaneously stop a recorder that has a data erasure feature and prevent each erasure feature from functioning, within 10 minutes after any crash impact; and
(b) Each non-ejectable recorder container must be located and mounted so as to minimise the probability of container rupture resulting from crash impact and subsequent damage to the record from fire.
(c) A correlation must be established between the flight recorder readings of airspeed, altitude, and heading and the corresponding readings (taking into account correction factors) of the first pilot’s instruments. This correlation must cover the airspeed range over which the aircraft is to be operated, the range of altitude to which the aircraft is limited, and 360° of heading. Correlation may be established on the ground as appropriate.
(d) Each recorder container must:
(1) Be either bright orange or bright yellow;
(2) Have a reflective tape affixed to its external surface to facilitate its location underwater; and
(3) Have an underwater locating device, when required by the applicable operating rules, on or adjacent to the container which is secured in such a manner that they are not likely to be separated during crash impact.
CS 27.1461 Equipment containing high energy rotors
ED Decision 2003/15/RM
(a) Equipment containing high energy rotors must meet sub-paragraphs (b), (c), or (d).
(b) High energy rotors contained in equipment must be able to withstand damage caused by malfunctions, vibration, abnormal speeds, and abnormal temperatures. In addition:
(1) Auxiliary rotor cases must be able to contain damage caused by the failure of high energy rotor blades; and
(2) Equipment control devices, systems, and instrumentation must reasonably ensure that no operating limitations affecting the integrity of high energy rotors will be exceeded in service.
(c) It must be shown by test that equipment containing high energy rotors can contain any failure of a high energy rotor that occurs at the highest speed obtainable with the normal speed control devices inoperative.
(d) Equipment containing high energy rotors must be located where rotor failure will neither endanger the occupants nor adversely affect continued safe flight.
CS 27.1470 Emergency locator transmitter (ELT)
ED Decision 2018/007/R
Each emergency locator transmitter, including sensors and antennae, required by the applicable operating rule, must be installed so as to minimise damage that would prevent its functioning following an accident or incident.
[Amdt No: 27/5]
AMC 27.1470 Emergency locator transmitters (ELTs)
ED Decision 2018/007/R
(a) Explanation
The purpose of this AMC is to provide specific guidance for compliance with CS 27.1301, CS 27.1309, CS 27.1470, CS 27.1529 and CS 27.1581 regarding emergency locator transmitters (ELT) and their installation.
An ELT is considered to be a passive and dormant device whose status is unknown until it is required to perform its intended function. As such, its performance is highly dependent on proper installation and post-installation testing.
(b) References
Further guidance on this subject can be found in the following references:
(1) ETSO-C126b 406 and 121.5 MHZ Emergency Locator Transmitter;
(2) ETSO-C126b 406 MHz Emergency Locator Transmitter;
(3) FAA TSO-C126b 406 MHz Emergency Locator Transmitter (ELT);
(4) EUROCAE ED-62A MOPS for aircraft emergency locator transmitters (406 MHz and 121.5 MHz (optional 243 MHz));
(5) RTCA DO-182 Emergency Locator Transmitter (ELT) Equipment Installation and Performance; and
(6) RTCA DO-204A Minimum Operational Performance Standards for 406 MHz Emergency Locator Transmitters (ELTs).
(c) Definitions
(1) ELT (AF): an ELT (automatic fixed) is intended to be permanently attached to the rotorcraft before and after a crash, is automatically activated by the shock of the crash, and is designed to aid search and rescue (SAR) teams in locating a crash site.
(2) ELT (AP): an ELT (automatic portable) is intended to be rigidly attached to the rotorcraft before a crash and is automatically activated by the shock of the crash, but is readily removable from the rotorcraft after a crash. It functions as an ELT (AF) during the crash sequence. If the ELT does not employ an integral antenna, the rotorcraft-mounted antenna may be disconnected and an auxiliary antenna (stowed in the ELT case) connected in its place. The ELT can be tethered to a survivor or a life raft. This type of ELT is intended to assist SAR teams in locating the crash site or survivor(s).
(3) ELT (S): an ELT (survival) should survive the crash forces, be capable of transmitting a signal, and have an aural or visual indication (or both) that power is on. Activation of an ELT (S) usually occurs by manual means but automatic activation (e.g. activation by water) may also apply.
(i) ELT (S) Class A (buoyant): this type of ELT is intended to be removed from the rotorcraft, deployed and activated by survivors of a crash. It can be tethered to a life raft or a survivor. The equipment should be buoyant and it should be designed to operate when floating in fresh or salt water, and should be self-righting to establish the antenna in its nominal position in calm conditions.
(ii) ELT (S) Class B (non-buoyant): this type of ELT should be integral to a buoyant device in the rotorcraft, deployed and activated by the survivors of a crash.
(4) ELT (AD) or automatically deployable emergency locator transmitter (ADELT): this type of automatically deployable ELT is intended to be rigidly attached to the rotorcraft before a crash and automatically deployed after the crash sensor determines that a crash has occurred or after activation by a hydrostatic sensor. This type of ELT should float in water and is intended to aid SAR teams in locating the crash site.
(5) A crash acceleration sensor (CAS) is a device that detects an acceleration and initiates the transmission of emergency signals when the acceleration exceeds a predefined threshold (Gth). It is also often referred to as ‘g switch’.
(d) Procedures
(1) Installation aspects of ELTs.
The installation of the equipment should be designed in accordance with the ELT manufacturer’s instructions.
(i) Installation of the ELT transmitter unit and crash acceleration sensors
The location of the ELT should be chosen to minimise the potential for inadvertent activation or damage by impact, fire, or contact with passengers, baggage or cargo.
The ELT transmitter unit should ideally be mounted on primary rotorcraft load-carrying structures such as trusses, bulkheads, longerons, spars, or floor beams (not rotorcraft skin). Alternatively, the structure should meet the requirements of the test specified in 6.1.8 of ED-62A. For convenience, the requirements of this test are reproduced here, as follows:
‘The mounts shall have a maximum static local deflection no greater than 2.5 mm when a force of 450 Newtons (100 lbf) is applied to the mount in the most flexible direction. Deflection measurements shall be made with reference to another part of the airframe not less than 0.3 m or more than 1.0 m from the mounting location.’
However, this does not apply to an ELT (S), which should be installed or stowed in a location that is conspicuously marked and readily accessible, or should be integral to a buoyant device such as a life raft, depending on whether it is of Class A or B.
A poorly designed crash acceleration sensor installation can be a source of problems such as nuisance triggers, failures to trigger and failures to deploy.
Nuisance triggers can occur when the crash acceleration sensor does not work as expected or is installed in a way that exposes it to shocks or vibration levels outside those assumed during equipment qualification. This can also occur as a result of improper handling and installation practices.
A failure to trigger can occur when an operational ELT is installed such that the crash sensor is prevented from sensing the relevant crash accelerations.
Particular attention should be paid to the installation orientation of the crash acceleration sensor. If the equipment contains a crash sensor with particular installation orientation needs, the part of the equipment containing the crash sensor will be clearly marked by the ELT manufacturer to indicate the correct installation orientation(s).
The design of the installation should follow the instructions contained in the installation manual provided by the equipment manufacturer. In the absence of an installation manual, in general, in the case of a helicopter installation, if the equipment has been designed to be installed on fixed-wing aircraft, it may nevertheless be acceptable for a rotorcraft application. In such cases, guidance should be sought from the equipment manufacturer. This has typically resulted in a recommendation to install the ELT with a different orientation, e.g. 45 degrees with respect to the main longitudinal axis (versus zero degrees for a fixed wing application). This may help the sensor to detect forces in directions other than the main longitudinal axis, since, during a helicopter crash, the direction of the impact may differ appreciably from the main aircraft axis. However, some ELTs are designed specifically for helicopters or designed to sense forces in several axes.
(ii) Use of hook and loop style fasteners
In several recent aircraft accidents, ELTs mounted with hook and loop style fasteners, commonly known from the brand name Velcro®, have detached from their aircraft mountings. The separation of the ELT from its mount could cause the antenna connection to be severed, rendering the ELT ineffective.
Inconsistent installation and reinstallation practices can lead to the hook and loop style fastener not having the necessary strength to perform its intended function. Furthermore, the retention capability of the hook and loop style fastener may degrade over time, due to wear and environmental factors such as vibration, temperature, or contamination. The safety concern about these attachments increases when the ELT manufacturer’s instructions for continued airworthiness (ICA) do not contain specific instructions for regularly inspecting the hook and loop style fasteners, or a replacement interval (e.g. Velcro life limit). This concern applies, regardless of how the hook and loop style fastener is installed in the aircraft.
Separation of ELTs has occurred, even though the associated hook and loop style fastener design was tested during initial European Technical Standard Order (ETSO) compliance verification against crash shock requirements.
Therefore, it is recommended that when designing an ELT installation, the ELT manufacturer’s ICA is reviewed and it is ensured that the ICA for the rotorcraft (or the modification, as applicable) appropriately addresses the in-service handling of hook and loop style fasteners.
It is to be noted that ETSO/TSO-C126b states that the use of hook and loop fasteners is not an acceptable means of attachment for automatic fixed (AF) and automatic portable (AP) ELTs.
(iii) ELT antenna installation
This section does not apply to the ELT(S) or ELT (AD) types of ELT. The most recurrent issue found during accident investigations concerning ELTs is the detachment of the antenna (coaxial cable), causing the transmission of the ELT unit to be completely ineffective.
Chapter 6 of ED-62A addresses the installation of an external antenna and provides guidance, in particular, on:
(A) the location of the antenna;
(B) the position of the antenna relative to the ELT transmission unit;
(C) the characteristics of coaxial-cables; and
(D) the installation of coaxial-cables.
Any ELT antenna should be located away from other antennas to avoid disruption of the antenna radiation patterns. In any case, during installation of the antenna, it should be ensured that the antenna has a free line of sight to the orbiting COSPAS-SARSAT satellites at most times when the aircraft is in the normal flight attitude.
Ideally, for the 121.5 MHz ELT antenna, a separation of 2.5 metres from antennas receiving very high frequency (VHF) communications and navigation data is sufficient to minimise unwanted interference. The 406 MHz ELT antenna should be positioned at least 0.8 metres from antennas receiving VHF communications and navigation data to minimise interference.
External antennas which have been shown to be compatible with a particular ELT will either be part of the ETSO/TSO-approved ELT or will be identified in the ELT manufacturer’s installation instructions. Recommended methods for installing antennas are outlined in FAA AC 43.13-2B.
The antenna should be mounted as close to the respective ELT as practicable. Provision should be taken to protect coaxial cables from disconnection or from being cut. Therefore, installation of the external antenna close to the ELT unit is recommended. Coaxial cables connecting the antenna to the ELT unit should not cross rotorcraft production breaks.
In the case of an external antenna installation, ED-62A recommends that its mounting surface should be able to withstand a static load equal to 100 times the antenna’s weight applied at the antenna mounting base along the longitudinal axis of the rotorcraft. This strength can be substantiated by either test or conservative analysis.
If the antenna is installed within a fin cap, the fin cap should be made of an RF-transparent material that will not severely attenuate the radiated transmission or adversely affect the antenna radiation pattern shape.
In the case of an internal antenna location, the antenna should be installed as close to the ELT unit as practicable, insulated from metal window casings and restrained from movement within the cabin area. The antenna should be located such that its vertical extension is exposed to an RF-transparent window. The antenna’s proximity to the vertical sides of the window and to the window pane and casing as well as the minimum acceptable window dimensions should be in accordance with the equipment manufacturer’s instructions.
The voltage standing wave ratio (VSWR) of the installed external antenna should be checked at all working frequencies, according to the test equipment manufacturer’s recommendations, during the first certification exercise for installation on a particular rotorcraft type.
Coaxial cables between the antenna and the ELT unit should be provided on each end with an RF connector that is suitable for the vibration environment of the particular installation application. When the coaxial cable is installed and the connectors mated, each end should have some slack in the cable, and the cable should be secured to rotorcraft structures for support and protection.
In order to withstand exposure to fire or flames, the use of fire-resistant coaxial cables or the use of fire sleeves compliant to SAE AS1072 is recommended.
(2) Deployment aspects of ELTs
Automatically deployable emergency locator transmitters (ADELTs) have particularities in their designs and installations that need to be addressed independently of the general recommendations.
The location of an ADELT and its manner of installation should minimise the risk of injury to persons or damage to the rotorcraft in the event of its inadvertent deployment. The means to manually deploy the ADELT should be located in the cockpit, and be guarded, such that the risk of inadvertent manual deployment is minimised.
Automatically deployable ELTs should be located so as to minimise any damage to the structure and surfaces of the rotorcraft during their deployment. The deployment trajectory of the ELT should be demonstrated to be clear of interference from the airframe or any other parts of the rotorcraft, or from the rotor in the case of helicopters. The installation should not compromise the operation of emergency exits or of any other safety features.
In some helicopters, where an ADELT is installed aft of the transport joint in the tail boom, any disruption of the tail rotor drive shaft has the potential to disrupt or disconnect the ADELT wiring. From accident investigations, it can be seen that if a tail boom becomes detached, an ADELT that is installed there, aft of the transport joint, will also become detached before signals from sensors that trigger its deployment can be received.
Therefore, it is recommended to install the ADELT forward of the transport joint of the tail boom. Alternatively, it should be assured that ELT system operation will not be impacted by the detachment of the structural part on which it is installed.
The hydrostatic sensor used for automatic deployment should be installed in a location shown to be immersed in water within a short time following a ditching or water impact, but not subject to water exposure in the expected rotorcraft operations. This assessment should include the most probable rotorcraft attitude when crashed, i.e. its capability to keep an upright position after a ditching or a crash into water.
The installation supporting the deployment feature should be demonstrated to be robust to immersion. Assuming a crash over water or a ditching, water may immerse not only the beacon and the hydrostatic sensor, which is designed for this, but also any electronic component, wires and the source of power used for the deployment.
(3) Additional considerations
(i) Human factors (HF)
The ELT controls should be designed and installed so that they are not activated unintentionally. These considerations should address the control panel locations, which should be clear from normal flight crew movements when getting into and out of the cockpit and when operating the rotorcraft, and the control itself. The means for manually activating the ELT should be guarded in order to avoid unintentional activation.
(ii) The rotorcraft flight manual (RFM) should document the operation of the ELT, and in particular, any feature specific to the installed model.
(iii) Batteries
An ELT operates using its own power source. The ELT manufacturer indicates the useful life and expiration date of the batteries by means of a dedicated label. The installation of the ELT should be such that the label indicating the battery expiration date is clearly visible without requiring the removal of the ELT or other LRU from the rotorcraft.
(4) Maintenance and inspection aspects
This Chapter provides guidance for the applicant to produce ICA related to ELT systems. The guidance is based on Chapter 7 of ED-62A.
(i) The ICA should explicitly mention that:
(A) The self-test function should be performed according to the manufacturer’s recommendation but no less than once every 6 months. Regulation at the place of operation should be considered when performing self-tests, as national aviation authorities (NAAs) may have established specific procedures to perform self-tests.
(B) As a minimum, a periodic inspection should occur at every battery replacement unless an inspection is required more frequently by the airworthiness authorities or the manufacturer.
(ii) Each inspection should include:
(A) the removal of all interconnections to the ELT antenna, and inspection of the cables and terminals;
(B) the removal of the ELT unit, and inspection of the mounting;
(C) access to the battery to check that there is no corrosion;
(D) a check of all the sensors as recommended by Chapter 7.6 of ED-62A — Periodic inspection; and
(E) measurement of the transmission frequencies and the power output.
(5) Rotorcraft flight manual (RFM)/Rotorcraft flight manual supplement (RFMS)
The rotorcraft flight manual (RFM) or supplement (RFMS), as appropriate, should contain all the pertinent information related to the operation of the ELT, including the use of the remote control panel in the cockpit. If there are any limitations on its use, these should be declared in the ‘Limitations’ section.
Detailed instructions for pre-flight and post-flight checks should be provided. As a pre-flight check, the ELT remote control should be checked to ensure that it is in the armed position. Post-flight, the ELT should be checked to ensure that it does not transmit, by activating the indicator on the remote control or monitoring 121.5 MHz.
Information on the location and deactivation of ELTs should also be provided. Indeed, accident investigations have shown that following aircraft ground impact, the remote control switch on the instrument panel may become inoperative, and extensive fuselage disruption may render the localisation of, and the access to, the ELT unit difficult. As a consequence, in the absence of information available to the accident investigators and first responders, this has led to situations where the ELT transmitted for a long time before being shut down, thus blocking the SAR channel for an extended time period. It is therefore recommended that information explaining how to disarm or shut down the ELT after an accident, including when the remote control switch is inoperative, should be included.
[Amdt No: 27/5]