Tailstrike - Tailstrike indication, warning &
protection
ATA:
31-28
FIN:
A/C Type:
A320
A321
A330
A340
A340-500
A340-600
A/C Serie:
Ref:
Topic:
Part Number:
31.28.00001
First Issue
Date:
23-JUL-2009
Last
Publication
Date:
07-MAY2014
Supplier:
Linked
Articles:
ISI
31.00.00019
Linked
Documentation:
Old Wise Ref:
engsup-12978
Engineering Support
Model:
First Issue Date:
23-JUL-2009
Last Publication Date:
07-MAY-2014
Manufacturer:
Description
A) TAILSTRIKE INDICATOR ON PFD
The Tailstrike indicator displayed on the Primary Flight Display (PFD) shall advise the flight
crew that the altitude (pitch angle) is such that the aircraft tail may strike the ground. The
Tailstrike indicator was first implemented on A340-500/-600 (on EIS2).
The tailstrike angle is received from the FG. The Tailstrike indicator is only displayed when
the tailstrike angle (in degree) is greater than 0. Moreover, the tailstrike indicator shall not be
displayed if the tailstrike angle is not valid or not computed by upstream computer (FG).
When the pitch angle is equal to the tailstrike angle, the aircraft tail hits the ground. The
Tailstrike indicator shall advise the pilot that the aircraft tail is closed to the ground.
When the pitch angle is equal to the tailstrike angle, the lower extremity of the "V" part of the
Tailstrike indicator shall touch the aircraft mock up whatever the kind of the aircraft mock up:
VBAR or not. In case of aircraft mock up without VBAR, the Tailstrike indicator will touch
the upper side of the centre square of the aircraft mock up if the pitch angle becomes equal to
the tailstrike angle.
The Tailstrike indicator shall be displayed as an amber "V" on the pitch scale and submitted
to the roll rotate as per the picture below:
A330/A340
Conditions for the Tailstrike indicator display
- the received tailstrike angle is valid,
- the received tailstrike angle data is not declared not computed,
- the received tailstrike angle data is strictly greater than 0,
Note that there is no dedicated hardware or software pin program to inhibit the tailstrike
indicator.
Display when VBAR option is activated :
the tailstrike indicator touches the aircraft mock-up when the pitch angle is equal to the
tailstrike angle. In this case, the projected value of the tailstrike angle is equal to the projected
value of the pitch angle.
Display when VBAR option is not activated :
the basic aircraft mock up is displayed on PFD. When the pitch angle is equal to the tailstrike
angle, the tailstrike indicator touches the upper side of the centre square of the aircraft mockup. In this case, the output value is equal to the projected value of the tailstrike + half the
height of the centre square of the mock-up.
There is no output data sent on output bus concerning the tailstrike angle, therefore no
required data for the DFDR.
The below minimum computer standards are required to activate the Tailstrike indicator
function.
A330
- EIS1 standard V512X (Mod 54225) or EIS2 L6-1 (Mod 53063),
- FG standard HJ1 (for PW & RR motorisations) or G1 (for GE motorisation).
A340-200/-300
- EIS1 DMC V111X (Mod 55662) or EIS2 L6-1 (Mod 53063),
- FMGEC "A11" standard (either via the FMS2 Pegasus P3A11 MOD 55615, or FMS2
THALES/Smiths T2A11 MOD 55353, or FMS1 Honeywell L10A11 MOD 56108).
A340-500/-600
Tailstrike indication function is basic from production on A340-500/-600.
A320 FAMILY
The Tailstrike indication function is relevant for A320 & A321 only. It is not necessary on
A319 & A318 aircraft.
Conditions for the Tailstrike indicator display
- the received tailstrike angle is valid,
- the received tailstrike angle data is not declared not computed,
- the received tailstrike angle data is strictly greater than 0,
- hardware pin program at FAC and DMC level is wired to GROUND.
Requirements:
- FAC B0619 standard (MOD 36766) with Pin-programm AB/6A grounded
- EIS2 S7 standard (MOD 36725) with Pin-programm AB/7J grounded
- FG:
CFM family :
FM HONEYWELL : P1C9 (MOD 32222)
FM THALES : S1C10 (MOD 32997)
IAE family :
FM HONEYWELL : P1I10 (MOD 35526)
FM THALES : S2I9 (MOD 34076)
B) "PITCH PITCH" AUTO CALL-OUT GENERATED BY FWC
The logics for PITCH PITCH auto callout are described in Wise article Flight Warning
Computer (FWC) - PITCH PITCH auto callout.
The below minimum computer standards are required to activate the "PITCH PITCH" auto
call-out.
A330
- FWC K8-1 standard coupled with FWC hard pin-programming activation,
- FMGEC T3HJ1, T3G1, P4HJ1, P4G1 (HJ1 for PW/RR and G1 for GE).
A340-200/-300
- FWC L10-1 standard coupled with FWC hard pin-programming activation,
- FMGEC "A11" standard.
A340-500/-600
"PITCH PITCH" auto call-out activation is basic from production on A340-500/-600.
A320 Family
- FWC H2-F3P standard,
- FAC B0619 standard,
- FAC Pin Programming.
C) TAILSTRIKE INDICATOR FOR ECAM WARNING GENERATED
BY FWC
The Tail Strike Indicator (TSI) is a breakable component used to indicate contact of aircraft's
rear fuselage with the ground. This component is housed in a fairing located at the point
where the rear fuselage would be touching the ground at maximum pitch limit. If the
component is broken in any way at aircraft take-offs or landings, it will indicate that a Tail
Strike has occurred.
The TSI provide two discrete signals to SDAC 1 and 2. The SDACs will process each discrete
input as "Ground" to indicate normal system configuration and "Open Circuit" as a Tail
Strike.
The TSI is made of two independent circuits that have the following characteristics:
Circuit 1:
The circuit goes "open" when 10mm (+/-2mm) of tail strike indicator is worn by ground
chafing during take-off or landing
Circuit 1 can stand abuse loads in any axis up to 650N without braking
Circuit 2:
The circuit goes "open" when the ground impact is greater that 650N and less that 5000N.
If the vertical load is greater than 5000N, the TSI will break off the aircraft at distinct TSI
location within the metal housing downwards the mounting flange.
This will cause permanent breaking of circuit 1 and 2.
Note:
If an "open" condition is detected at take-off or landing, the ECAM warning "TAIL STRIKE"
will be triggered.
If an "open" condition is detected on ground, the ECAM warning "TAIL STRIKE DET
FAULT" will be triggered.
If an "open" condition is detected in flight, out of take-off or landing phase, this will arm the
ECAM warning "TAIL STRIKE DET FAULT".
To activate Tail Strike Detection through Tail Strike Indicator, the below minimum system
standards are required:
A330:
- FWC K9 standard to provide the ECAM warning.
- SDAC C8 standard to provide acquisition interface between TSI and FWC.
- TSI and associated wiring : to provide information to SDAC.
- pin programming at SDAC level : to activate the TSI logics with FWC.
A340-200/-300
- FWC L11: to provide the ECAM warning.
- SDAC C8 : to provide acquisition interface between TSI and FWC.
- TSI and associated wiring : to provide information to SDAC.
- pin programming at SDAC level : to activate the TSI logics with FWC.
A340-500/-600
TSI, FWC, SDAC and pin-programming activation are basic from production.
A320 Family
The tailstrike detection through Tailstrike Indicator is not available on A320 Family.
D) TAILSTRIKE ACTIVE PROTECTION (FLIGHT CONTROLS
FEATURE)
This function consists in reducing the elevator authority in specific flight conditions in order
to avoid any tail strike. This function is hosted by the Flight Controls computers.
The below minimum computer standards are required to activate Tail Strike Active
Protection:
A330
- available on MRTT only
A340-200/-300
- L19 standard (FCPC xx2K2xxxxx)
- L20 standard (FCPC xx2K0xxxxx)
A340-500/-600
- FCPC W1 standard
A320 family
- ELAC: L93 standard
Survey for the Engineering Support section
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