tl:dr;

The Radio Altimeter Aux output was only operational between .4v and 3 v or so.  This made the ground prox see the Radio Altitude as 348 feet at all times.  This subtle failure was missed three times on the bench.

 

Cl 601 …A

 

 

RESOLUTION:

 

A loaner Rad Alt box fixed the EGPWS call out problem.

 

Here is the video of the EGPWS working properly

http://youtu.be/xm16feftWR0

Squawk:  EGPWS gives “Pull Up”  “Terrain” in flight

Supporting facts about squawk:  

1. Fault occurs during clmb, or first level off, AFTER 2000 to 3000 feet.

2. Associated “Pull Up”  “Terrain” on ground was fixed by properly setting zero.

3. The number 1 and number 2 IRU’s have been swapped just in case the problem was IRUAlt.(??2 IRU inputs?)

Details about EGPWS

 

> ps

EGPWC CONFIGURATION:
PART NUMBER: 965-0976-003-214-214
MOD STATUS: 10
SERIAL NUMBER: 17306

APPLICATION S/W VERSION: 214.2
CONFIGURATION S/W VERSION: 214.11
TERRAIN DATABASE VERSION: 473
ENVELOPE MOD DATABASE VERSION: B07
BOOT CODE VERSION: B101.2

CURRENT FAULTS:

GPWS COMPUTER OK

GPWS EXTERNAL FAULTS:
IRS BUS INACTIVE
EFIS BUS INACTIVE
FMC BUS INACTIVE

———-
Envelope Modulation INOP
Terrain Clearance Floor – Position Error

PROGRAM PIN CONFIGURATION:
Aircraft Type = 85
Audio Menu = 0
Altitude Callout Menu = 15
Configuration Option 2 Selected
Smart Callout Selected
Optional Inputs Selected
Dual GPS Selected
Windshear Caution with Voice Selected
Bank Angle Selected
Peaks Enabled
Mode 6 Low Volume Selected
Terrain Awareness and TCF Disabled
Obstacle Awareness Enabled

RAW PROGRAM PIN STATES:
Program Pin 1 (TP-10A) = 6 (TP-12C)
Program Pin 2 (TP-10B) = 3 (MP-15D)
Program Pin 3 (TP-10C) = 2 (MP-03A or Gnd)
Program Pin 4 (MP-04D) = 8 (TP-04D)
Program Pin 5 (MP-04B) = 2 (MP-03A or Gnd)
Program Pin 6 (MP-08A) = 5 (MP-07B)
Program Pin 7 (MP-14D) = 6 (TP-12C)
Program Pin 8 (MP-05A) = 1 (Open)
Program Pin 9 (MP-02C) = 1 (Open)
Program Pin 10 (MP-04A) = 1 (Open)
Program Pin 11 (MP-04C) = 1 (Open)
Program Pin 12 (TP-05B) = 4 (MP-03D)
Program Pin 13 (MP-05B) = 3 (MP-15D)
Program Pin 14 (TP-02C) = 2 (MP-03A or Gnd)
Program Pin 15 (MP-15C) = 1 (Open)
Program Pin 16 (MP-08B) = 5 (MP-07B)
Program Pin 17 (TP-06D) = 1 (Open)
Program Pin 18 (MP-15A) = 1 (Open)
Program Pin 19 (MP-15B) = 1 (Open)

 

Initial Pilot video of squawk:

http://youtu.be/dm5NXfQ25Co, Video shows Baro ASL 3000 – level.  The Rad Alt shows 2200 feet to 2350 feet, makes sense around the DFW area, ground level is 750 feet or so.

RadAlt RT300 has been to Lincoln “3 times”.

P/N  S/N

Apr_30_2015_8130 (1)   replace Downconverter

May_16_2014_8130 (2)  Capacitors

June_25_2015_8130 Resistor, connector

 

 

EGPWS has been to Honeywell,

Egpws work report  work report. No Fault found.

Deeper troubleshooting at RadAlt input:

Duncan has rung out Rad Alt Aux wires.

Chuck at AAT put a volt meter on the EGPWS 13A and 13B:

0Feet = .367 volts DC.  100 foot test = ~2.36 VDC,

EGPWS Air Inc 552 voltages and wires

Video http://youtu.be/tNAsbRlpKNk

Ground troubleshooting in WinViews:

Ground test FAULTS

> FHW
WARNING HISTORY:

FLIGHT LEG 1:
TCF TooLowTerrain ( 4771:58:39)
TCF TooLowTerrain ( 4772: 1:13)
TCF TooLowTerrain ( 4772: 4: 4)
M3 Don’tSink (Pause) Don’tSink ( 4772: 4: 8)
M1 Sinkrate ( 4772: 4:27)

FLIGHT LEG 2:
M3 Don’tSink (Pause) Don’tSink ( 4771: 6:35)
M3 Don’tSink (Pause) Don’tSink ( 4771: 6:46)
M3 Don’tSink (Pause) Don’tSink ( 4771:26: 5)
M3 Don’tSink (Pause) Don’tSink ( 4771:27:44)
M3 Don’tSink (Pause) Don’tSink ( 4771:27:46)

…….and so forth

 

(Use CXR RawARA1)

0 Feet = -1.3 to -2.0 feet (Parameter RawARA1)

100 foot test = 98.7 feet

> cxr RawARA1
RawARA1 97.557308 Cstm=0x00000167 Flg=0x00000000 T.Upd=213400
Usr=3 psDEFAULT +VALID
> cxr RawARA1
RawARA1 23.977366 Cstm=0x000000A7 Flg=0x00040000 T.Upd=215290
Usr=3 psDEFAULT FW+VALID
> cxr RawARA1
RawARA1 -2.082198 Cstm=0x00000064 Flg=0x00000000 T.Upd=217200
Usr=3 psDEFAULT +VALID

 

IN AIR results from WinViews

With Baro reading 3000, EFIS RA reading ~2300 FT……..

RawARA1 is only 354 feet.   THATS BAD.

RawIALT1 was about 2900 feet.

 

WHAT SHOULD THE VOLTAGE BE AT 480 feet AGL:

V = .02*h +20

=10 volts for 480 feet.

 

WHAT SHOULD THE  VOLTAGE BE AT 2500 feet AGL:

According to DAC international Install Manual,

Volts = 10*(1+LN((ALT + 20)/500) so 2500 feet is 26.16 VDC…… correct because 480 feet works out to 10VDC, same as low formula

WRONG……..According to the RT 300 book

Volts = 10* LN((ALT + 20)/500) so 2500 feet is 11.6 VDC  .. WRONG

 

EGPWS works correctly with loaner Rad Alt RT

 

Challenger working notes

rad alt delay lines work card

Delay line DataSheet

DelayLine1503

Balser 817 781 9859

Harold Henderson 818 398 1425

Scott Mckinney at Duncan 402.479.4212

Josh  DOM AAT 817 507 8676

Jorje 817 395 3382

Joel 214 714 6289