Aircraft Bonding Jumper

Aircraft Bonding Jumper

There were various types of bonding jumper i.e. P/N MS25083-2BB4, P/N BACJ40A20-9, P/N BACJ40K5A5A6, P/N BACJ40AD57-11 and P/N 69-14402-1 installed on Boeing airplane at various locations.

The following are partial description of the referenced bonding jumpers:

a) Bond Jumper P/N MS25083-2BB4 JUMPER ASSEMBLY, ELECTRIC, BONDING AND CURRENT RETURN (S/S BY MIL-C-83413/8) (per Mil-C-25083 4.0 inch long)

b) Bond Jumper P/N BACJ40A20-9 JUMPER ASSEMBLY, BONDING, COPPER, 35 AMPERE (0.190 & 0.190 Studs, 9 Inch Long)

c) Bond Jumper P/N BACJ40K5A5A6 JUMPER, BONDING, IRRADIATED, POLYOLEFIN, NYLON INSULATED TERMINAL (BMS3-11 RESISTANT) (0.190 & 0.190 Studs, 6 inch long)

d) Bond Jumper P/N BACJ40AD57-11 JUMPER ASSEMBLY, 35 AMPERE (0.250 & 0.375 studs, 11 inch long)

e) Bond Jumper P/N 69-14402-1 STATIC BONDING JUMPER, 60 amp braided tinned copper stranding (9.60 INCH LONG, STUD HOLES SLOTTED 0.14 radius WITH 0.10 CENTER OFFSET both ends)

The bonding check after installation is available via D6-54446 Standard Wiring Practices Manual (SWPM) Subject 20-20-00, and depends on the surface material and stud diameter.

Selection of a bonding jumper is based on current and frequency requirements and characteristics, material compatibility, installation geometry, environment, etc.
The selection of bonding jumpers is determined by the engineering design organization based on the specific requirements for the environment, application and other factors available at the time of design as discussed above. The reasons for a determination of a specific selection or design are not recorded, at least not with the selection. The parts or specification are available for each location in the respective IPC chapters listing the components for each area. Operator is encouraged to adhere to this selection or as specified in the drawing if not listed in the IPC.

Any deviations from the design drawing must be evaluated by Boeing.

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Boeing Aircraft Paint Spec

Boeing Aircraft Paint Spec

Boeing provides some infos on the paint spec for the external antennas.
Basically, the antennas should not be painted over i.e. Marker Beacon Antenna and ADF Loop Antenna.
Radio Altimeter Antenna is straightly NOT recommended to be painted.
Most antennas installed on airplanes are already been painted by the antenna manufacturers.
Boeing has not developed any procedures to carry out cosmetic repairs or rework on the antenna.

Discussion:
As a general rule, the antennas should not be painted over. Most antennas installed on airplanes are already painted by the antenna manufacturers and Boeing does not paint over these antennas nor does Boeing recommend painting over them.
While Boeing does not develop procedures for the maintenance of vendor build parts, if an antenna is not damaged structurally and only requires cosmetic repairs, we have found that the following generally does not effect system performance: Apply BMS 10-60 Type II polyurethane enamel or an equivalent paint which is non-metallic, skydrol resistant epoxy enamel or polyurethane enamel. This paint should be applied in accordance with BAC5845. If a primer is required, Boeing suggests the use of BMS 10-79, Type II or III.
Note: Antennas must be re-tested after being re-painted.
The following more specific guidelines are offered for your consideration:

VHF Communication Antenna:
This antenna is BFE, was supplied by Sensor and is supplied by Dorne and Margolin. The suppliers prefer to have operators return the antennas to them for repair. Also, painting the antenna voids the manufacturer warranty. Therefore we don't recommend painting it. However, if the operator must paint the antenna, Boeing recommends using non-metallic, BMS10-60, Type II polyurethane enamel, color white, applied per BAC5845.

VHF (VOR/ILS) Navigation Antenna:
This antenna is an integral part of the vertical fin. Boeing has no objection to painting the VHF Nav Antenna with non-metallic, BMS10-60, Type II polyurethane enamel, applied per BAC5845.

Marker Beacon Antenna:
Boeing recommends that the Marker Beacon Antenna should not be repainted by the operator. This is a high Q antenna and is sensitive to the finish that is applied. It is recommended that the antenna be returned to the vendor for refurbishing.

ADF Sense Antenna:
Boeing has no objection to painting this antenna.

ADF Loop Antenna:
Repainting the ADF Loop Antenna is generally not recommended by vendors and no repainting instructions are provided.

Radio Altimeter Antenna:
Repainting the RA Antenna is not recommended.

Note: The metal rim around the RA Antenna may be painted for corrosion protection, but it is critical to system performance that the fastener holes and countersunk areas around the holes be free of paint and making surface to surface contact with the airplane.

ATC / DME Antenna:
Painting the antenna voids the manufacturer warranty. Therefore we don't recommend painting it. If the operator must paint this antenna, use paint using BMS10-11, Type II epoxy enamel, color BAC201 orange, applied per BAC5736.

TCAS Antenna:
Do not paint. The TCAS Antennas installed by Boeing arrive from the TCAS suppliers fully finished. Since this antenna uses very low signals to determine the direction of incoming signals, the TCAS suppliers have advised BOEING in the past that they do not recommend operators paint the TCAS Antenna. Boeing suggests that the appropriate TCAS Vendor be directly contacted for advice on Antenna painting.



Question and Answer

1) What are the paint specs for external antenna?
The paint specifications for external antennas are controlled by the individual vendors supplying each antenna. Boeing does not specify nor have detailed knowledge of these individual paint specifications.

2) Can Boeing recommend the type of paint those normally use to paint external antenna (i.e. type & P/N)?
Boeing does not recommend painting over external antennas. However, if an antenna must be painted, we suggest using BMS 10-60 Type II polyurethane enamel or an equivalent paint which is non-metallic, skydrol resistant epoxy enamel or polyurethane enamel. If a primer is required, Boeing suggests the use of BMS 10-79, Type II or III.

3) Please advices if paint below can be used to paint the external antenna?
High Solids Polyurethane Enamel Topcoat (Eclipse Series) White Topcoat Gloss P/N: BAC70846 Spec BMS 10-72 and primer High Solid electrostatic Epox Primer P/N: 10P20-44 Spec BMS 10-72.
Subject to restrictions listed in the preceding "Discussion" section, Boeing has No Technical Objection (NTO) to the use of the decorative paint system defined below for use in painting external antennas:
- High Solids Polyurethane Enamel Topcoat (Eclipse Series) White Topcoat Gloss P/N: BAC70846 Spec BMS 10-72 and primer High Solid electrostatic Epox Primer P/N: 10P20-44 Spec BMS 10-72.
Note: While Boeing has reviewed the available technical information on this paint as proposed for this use and it appears to satisfy form, fit and function requirements, Boeing has not tested nor certified it for this particular use. Therefore, after painting, it is recommended that you perform airplane tests to verify satisfactory system operation of each antenna.

4) Is there any Boeing Services Letter with regards to the External Antenna Painting or Antenna Rework / Repair?
Boeing has not prepared or released any Services Letter on rework / repair of vendor supplied antennas.

5) We understood that Marker Beacon Antenna should not be painted and ADF Loop Antenna and Radio Altimeter Antenna are straightly NOT recommended to be painted. Please advice if Boeing has come out with any Service Letter with regards to this?
Boeing has not prepared or released any Services Letter recommending that the Marker Beacon Antenna, the ADF Loop Antenna or the Radio Altimeter Antenna NOT be painted.

6) Kindly advice the proper procedure to carry out cosmetic repairs or rework on the external antenna?
For vendor supplied antennas, Boeing has not developed any procedures to carry out cosmetic repairs or rework.
Note: For vendor supplied antennas when the damage has been only cosmetic such as non-penetrating minor paint scratches, there are antennas which Boeing has painted using BMS 10-60 Type II polyurethane enamel or an equivalent paint which is non-metallic, skydrol resistant epoxy enamel or polyurethane enamel. In these cases, Boeing has found that system performance has not been degraded. This work has included limited sanding, use of some primer and application of less than 3 mils of the paint.


Source of References
1) Boeing MESSAGE NUMBER:1-1JLT7F dated 12 May 2005
2) Boeing MESSAGE NUMBER:1-1K31I4 dated 13 May 2005

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LANGKAWI INTERNATIONAL MARITIME & AEROSPACE EXHIBITION LANGKAWI, MALAYSIA | 1 - 5 DECEMBER 2009

THE WORLD'S PREMIER MARITIME & AEROSPACE EXHIBITION

Malaysia is once again proud to play host to the 10th edition of the LIMA Exhibition, which will be held from 1 – 5 December 2009 in Langkawi.

The Langkawi International Maritime and Aerospace Exhibition is the premier destination for aerospace and maritime manufacturers targeting the Asia Pacific growth markets. For nearly 20 years, LIMA has been serving exhibitor needs by assembling key decision makers from the defence, enforcement and civil sectors.

 

Exhibition Program

Opening Hours

1 – 4 December 2009

Trade Visitors Only: 1000-1700

5 December 2009

Public: 1000-1700 

Download exhibition program at http://www.lima.com.my/pdf/Event_Programme.pdf

Trade Visitors

Trade Visitors may register online before attending LIMA '09! You make payment and collect your pre-prepared passes at the Registration Counter on site. The fee is RM50 for multiple entries.

 

Public Visitors 

The 5th of December is opened to public visitors. Visitors may register onsite at registration counter at a fee of RM20 per person whilst children under 12 may attend free of charge.

Visitor Attire

The organizer reserves the right to refuse entry to visitors in jeans, Bermudas, shorts sandals, slippers or sports shoes and to minor below 18 years old.

For More Details....Visit

http://www.lima2009.com.my/index.php

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A319/320/321 - Cockpit Door Surveillance System- Reliability Improvement

A319/320/321 - Cockpit Door Surveillance System- Reliability Improvement

Background/Reason:

CDSS Cameras P/N 8410B1-101-105 and 8410B2-4-90 installed on A319/320/A321 fleet have experienced premature removals due to internal short circuit in the power supply board.
The aim of this task is to perform a campaign check of the CDSS Cameras MOD status and carry out an upgrade of the installed ones, which do not have MOD “A” and or MOD “B” incorporated at the label P/N.

Material Requirement
1) P/N 8410B1-101-105 MOD A (Goodrich); Flight Crew Door Camera
2) P/N 8410B2-4-90 MOD A & B (Goodrich); No1 Passenger Crew/L/H and R/H Doors Camera

References
1) Airbus A319/320/321 AMM 23-72-00

Accomplishment Instructions
WARNING: Observe all warning and caution given in the referenced AMM TASK.

1) Get access to the avionics compartment. Open, safety and tag the related CBs refer to AMM TASK 23-72-51-000-001

2) Remove Camera P/N 8410B1-101-105 FIN # 12 RA installed on front cockpit door as per AMM Removal / Installation TASK 23-72-51-000-001.

3) Check identification Label on the Camera. FIN # 12 RA

a) IF MOD “A” is indicated on the P/N plate, no further action is required, reinstall Camera as per AMM Task 23-72-51-400-001.

b) If MOD A is not indicated on the label P/N, attach U/S label and write “Unit to be modified”

c) Record in the attached feedback form and with findings.

d) If Camera S/N is affected as per the attached SIL and P/N 8410B1-101-105MOD “A” is not indicated on the Label P/N. Attach U/S Label and writes “Unit to be modified as per CMA 23-37 R03”

4) Install the modified camera FIN # 12A P/N 8410B1-101-105 with MOD “A” incorporated on the Label P/N as per AMM Task 23-72-51-400-001

5) Remove Camera FIN# 13 RA P/N 8410B2-4-90 installed on No1 passenger/crew LH
as per AMM Removal / Installation TASK 23-72-51-000-001

6) Remove Camera FIN # 14RA P/N 8410B2-4-90 installed on No1 Passenger/Crew RH
door as per AMM Removal / Installation TASK 23-72-51-000-001

7) Check identification Label on the Cameras FIN # 13 RA and 14 RA.

a) If both MOD “A” & MOD ”B” are indicated on the P/N plate; no further action is required, reinstall Cameras as per AMM Task 23-72-51-400-001

b) Record in the attached feedback form with findings.

c) If P/N 8410B2-4-90 MOD “A” OR MOD “B” is not indicated on the Label P/N. Attach U/S Label and write “Unit to be modified”

8) Install the modified camera FIN # 13 RA P/N 8410B2-4-90 with MOD “A” & MOD “B” incorporated on the label P/N as per AMM Task 23-72-51-400-001

9) Install the modified camera FIN # 14A P/N 8410B2-4-90 with MOD “A” & MOD “B” incorporated on the label P/N as per AMM Task 23-72-51-400-001

Test
10) Do the operational test of all cameras FIN # 12 RA, 13 RA and 14 RA as per AMM Task 23-72-00-710-001

Close-up
11) Return the A/C to normal operations conditions, as per AMM Sub task.23-72-00-862-051

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MD-11F Autoland Cat II

MD-11F Autoland Cat II

1) MD-11F is FAA approved to perform various levels of Autoland approaches with the equipment listed in the Autopilot Automatic Landing Configuration (AALC) table shown in the MD-11F AFM, section 3 (Procedures).

2) P to F conversion does not affect Autoland operation. AFM covers both MD-11 & MD-11F is up-to-date and there are no differences between passenger and cargo config with regard to autoland system.

3) As stated in MD-11F AFM Section 1 (Limitation);

- Autoland operation requires incorporation of SB MD11-22-004 or the production equivalent.

- DO NOT perform Autolands when the aircraft gross weight is less than 305,000 lb and this limitation does not apply when SB MD11-22-14 or its production equivalent is incorporated.

- Automatic landings are prohibited above 8000 feet MSL and at weights greater than 481,500 lb. If an LSAS failure is annunciated enroute, the failed LSAS channel must remain in the OFF position for Autoland operations and landing weather minima credit with wing engine inoperative, may not be based on use of the automatic landing system. A manual landing is required if a wing engine N1 RPM indicator reverts to Amber “X” between 1000 feet AGL and 200 AGL. This limitation does not apply when SB MD11-22-005 or its production equivalent is incorporated.

- Three (3) hydraulic systems must be operative for DUAL LAND operations although “DUAL LAND” may be displayed when one hydraulic system is inoperative. This limitation does not apply when SB MD11-A31-001 or production equivalent is installed.

4) AMM has an additional test requirements procedure for Autoland operational status. Table below are the details of the additional test requirements for each of the components related to Autoland:

No Description AMM refer
1 Flight Control Computer Task 22-01-01-741-801
2 Autoflight System Control Panel Task 22-00-02-700-801
3 Autopilot Disconnect Switches Task 22-00-06-700-801
4 Auto Throttle Servo Task 22-00-07-700-801
5 Auto Throttle Disengage Switches Task 22-00-07-700-801
6 Electrical Power Control Unit Task 24-08-01-741-801
7 Inboard/Outboard Aileron Actuators Task 27-13-00-741-801/802
8 Rudder Actuators Task 27-23-00-741-801
9 Inboard/Outboard Elevator Actuators Task 27-33-00-741-802/803
10 Flap Synchros Task 27-54-00-741-801
11 Glareshield Control Panel Task 22-00-04-700-801
12 Wheel Speed Transducers Task 34-45-03-741-801
13 Inertial Reference System Task 34-43-00-700-803
14 Air Data Computers Task 34-16-01-741-801
15 ILS Receiver Task 22-01-01-741-801/802
16 Glideslope Antenna Relay Task 34-32-03-741-801
17 Radio Altimeter Task 34-42-01-741-801
18 FADEC Task 73-21-02-741-868

Note: Each component related to Autoland has and additional task written “To keep the aircraft approved for CATEGORY IIIb status, do the …….”

5) MD-11 Maintenance Schedule includes the additional test requirements to return aircraft to Autoland operational status after maintenance.

6) MD-11F FCOM does reflect the procedures such as the “SINGLE LAND” and “NO AUTOLAND” alerts which indicate the land availability of the aircraft. “SINGLE LAND” indicates that CAT II approach may be continued automatically. “NO AUTOLAND” indicates that there is insufficient equipment redundancy to perform an automatic landing. MD-11 FCOM (B/MD11/FCOM/P563.1D) refers.

7) MEL Procedure Manual (MDC K5511) item 22-10-3 also reflects relief of Automatic Landing System (Autoland) and provide procedure to install PLACARD “AUTOLAND INOP” and in addition to the alert “NO AUTOLAND” that will shows in EAD.


References
a) Boeing message dated 31st Oct 2005
b) AFM MDC-K0041 Rev 82 dated 15 Mar 05
c) AFM MDC-K0041 Rev 84 dated 28 July 05
d) MEL Procedure Manual (MDC K5511)
e) Aircraft Maintenance Schedule.
f) MD11Aircraft Maintenance Manual (AMM)
g) MD-11 FCOM (B/MD11/FCOM/P563.1D)

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Aircraft Polar Route Operations

Polar Route Operations

A. Introduction

1. New cross-polar routes connect eastern and interior regions of North America to Asian cities via Polar Region which provides an attractive shortcut to Asia (Polar 1, 2, 3 and 4).

2. The advantages are obvious; it reduces the flight time, increase the payload and also there is the absence of turbulence.

3. Polar routes operate under extreme temperatures in the Artic environment where suitable and alternate airports are limited.

4. There are many major Airlines operating the polar routes, notably United, Continental, Northwest, Delta, Air Canada. Air China, Russia KrasAir and Cathay Pacific.

5. The following should be considered when conducting polar routes operation:
A) Regulatory guidance
B) En route alternate airport
C) Cold fuel management
D) Communication and navigation

B. Regulatory guidance

1. Obtain info from local authority and FAA on the specific requirement to conduct polar operations i.e. approval and to provide flight plan – Flight Ops

2. Prepare the Airline Recovery Plan for unplanned diversion that address the care & safety of crew at the diversion airport and provide the plan to transport crew from that airport – Flight Ops

3. Prepare the Long Range Flight Crew Rest Plan and a clear progression of pilot-in-command authority – Flight Ops

4. Liaise with Boeing to develop a Fuel temperature analysis and monitoring program – Engineering

5. Verify that acft is fitted with effective communication system i.e. VHF(Voice and data link), HF(Primary) & SATCOM (Back-up) – Engineering

6. Amend Minimum Equipment Lists (MEL) to indicate the following equip/systems are required for north polar operations dispatch – Engineering
1) FQIS (include fuel tank temperature indicating system)
2) Auto-throttle system
3) Autopilot
4) Communication systems i.e. HF and VHF (Voice & ACARS), (SATCOM – backup system)

7. Conduct training for flight crew and maintenance on Polar Route Operation (i.e. QFE, QNH and meter altimetry, cold temp alt correction proc, fuel management proc, weather pattern and cold weather anti-exposure suits) – Flight Ops and Engineering

8. Ensure a minimum of two (2) cold weather anti-exposure suits to be on board the acft – Engineering

9. Conduct an DCA-observed validation flight in order to receive authorization to conduct polar operations – Flight Ops

10. In the event of any emergency landing for aircraft flying over substantially uninhabited land areas in polar conditions are likely to be met MCAR scale V, which requires the following:
1) One survival beacon radio apparatus,
2) Marine type pyrotechnical distress signal
3) 100 gm of glucose toffee tablets for each 4 persons on board
4) Half liter of fresh water in durable containers for each 4 persons on board
5) First aid equipment
6) One stove suitable for use with acft fuel for every 75 persons
7) One cooking utensil in which snow or ice can be melted, two snow shovels and two ice saws
8) Single or multiple sleeping bags
9) Artic survival kit


C. En Route Alternate Airports

1. Flight Ops to identify the alternate airports along a routes which must have
a capability such as airplane can land safely at the existing runway, diverted airplane can be cleared from the runway, crew are able to deplane in a safe manner, facilities near the airport and recovery plan can be executed and completed within 12 to 48 hrs after diversion – Flight Ops

D. Cold Fuel Management

1. Verify that MD-11 is fitted with fuel temperature probe located in the outboard compartment of tank no 3 and in the horizontal stabilizer tank and Low Fuel Temperature indicator is displayed on Display Unit – Engineering

E. Communication and Navigation

1. Polar route operations require VHF and HF systems to communicate with ATC. SATCOM should be considered only as a backup as it is not available above 82 deg north latitude.

2. Aircraft entering Russian airspace on Polar 1 and Polar 2 are controlled by the Murmansk ATC center near the Finnish border and those entering Polar 3 and Polar 4 are under Magadan’s watch located in Russia’s east coast.

3. GPS and IRUs provide navigation over the polar route. Aircraft is recommended to equipped with dual GPS and triple IRUs; which is fitted on MD11.

References:
i) Aero Magazine of Oct 2001
ii) OPSPEC B055 on North Polar Operations in the Air Transport Operations Inspectors Handbook Order 8400.10, Volume 3
iii) Civil Aviation Regulations (CAR)

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B737 - ACAS II Potential Interference between Cargo Door Modification and Upper Directional Antenna

Aircraft : B737-200
Defect : ACAS II Potential Interference between Cargo Door Modification and Upper Directional Antenna

Spurious ACAS II signals had been reported after aircraft undergone freighter modification. ACAS II system was installed at SZB just prior to freight modification. Main Cargo Door (MCD) hinge fwd end protrudes by about 1 inch at the fwd-most end.

ACAS II system was tested using T-49C Test Set for bearing testing and air mode (2500 feet) simulated using Pitot Static Test Set. Various situations/scenarios were checked to verify most probably cause of these spurious signals together with radio LAE.

Scenario 1 - ACAS II Upper Directional Antenna at the existing location (BS 385), carried out outside hangar.

1) A few seconds after switching 'ON' the ACAS II system (T-49C is still 'OFF'); IVSI displayed:
- Nuisance intruder (diamond shape with no identification and altitude) appeared outside the RA ring (about 45 degree) for a short while. After 1 second, it appeared at different angle (about 225 degree) and moved around the ring and disappeared.
- Sometimes this nuisance intruder (diamond shape with no identification and altitude) appeared more than one place (2 or 3) at the same time at various angles.

2) Using T-49C for bearing testing transmitted at angles of 0, 225, 270 and 315o below were displayed on the IVSI:
- Intruder with identification and altitude (as setting on T-49C) coming in from the correct angle and altitude as per setting. The intruder with the diamond shape (solid, white) changed to circle (Amber, solid) and aural warning (Traffic alert) was audible once intruder entered the 2 nm range ring. This is correct indication.

3) However, at angles of 45, 90, and 135 o, we found the following discrepancy on the IVSI:
- Intruder with identification and altitude (as setting on T-49C) as per (2) above; and at the same time, nuisance intruder with identification and altitude (as setting on T-49C) coming in from incorrect angle (180 degree from the transmitted angle) and disappeared once it enter the 2 nm range ring. This seems to be a reflected signal probably caused by the MCD door hinge. However the correct indication was not affected by this spurious signal.

4) Once in a while we saw the nuisance intruder (diamond shape with no identification and altitude) appeared outside the ring and disappeared after 1 second and re-appeared again for short durations at different angle (at various angles).

5) At the same time an actual aircraft was flying above our acft and we saw the correct traffic shown on IVSI (intruder with identification and altitude) coming from LEFT of the acft (at angle of 225 to 360 degree) with clean signal (no reflection or erratic). There was NO aural warning or traffic alert since aircraft is flying above our acft on ground.

Summary of Scenario 1
Based on the findings, the system is functional except the reflection image of intruder (nuisance) when an aircraft approaches at angles of 45, 90, and 135o. The nuisance intruder (TA diamond) disappears once it goes into the RA circle. The correct intruder is still shown on IVSI and provides a correct visual warning: blank diamond shape (white) changes to solid (white) and then once inside the 2 nm range ring, diamond shape changes to circle (Solid, Amber). Aural warning (TA and RA) is audible once intruder enters the 2 nm range ring. Correct indication maintains its true path. Therefore system is considered operative except for the spurious signals that typically last few seconds.

Scenario 2 - ACAS II Upper Directional Antenna at the existing location (BS 385) and the height is temporarily adjusted upwards by installing the 1 cm thick spacer. (Note: new bonding less than 2.5 milliohms as we use a wire jumper to bond to acft frame). Carried out on 31st Jan 2007 outside the hangar.
Findings as shown on the IVSI:

6) Same as Scenario 1 findings except this time we notice that there is NO nuisance intruder (diamond shape with no identification and altitude) on the IVSI per described in Scenario 1 para (1).

Summary of Scenario 2
Situation is only improved slightly with the antenna adjusted upwards.

Scenario 3 - ACAS II Upper Directional Antenna is moved fwd temporarily 2 feet from the existing location BS 385) and at the same stinger. (Note: new bonding less than 2.5 milliohms as we use a wire jumper to bond to acft frame). Carried out outside hangar.

7) Powered up with no signal from tester, same per described in Scenario 1 para (1).

8) Transmitted signal using T-49C at angles of 0, 225, 270 and 315o.
- Finding same as described in scenario 1 para (2). This is correct indication.

9) Transmitted signal using T-49C at angles of 45, 90, and 135o.
- Finding same as described in scenario 1 para (3). Correct indication with additional transient ghost indications.

10) Transmitted signal using T-49C directed to the cargo door hinge at angle of 90 degree (see figure)



IVSI displayed:
- Nuisance intruder with identification and altitude (as setting on T-49C) coming in at about 210 o i.e. from behind the acft and disappeared once it entered the RA ring.
- Nuisance intruder moved away from the acft at the same angle (210o).
- We believed this happened due to the reflection created by the MCD hinge.

11) During test we saw an intruder with identification and altitude (one aircraft was flying above) coming from the LEFT (at angle of 225 to 360o) with clean signal (no reflection or erratic)
At the same time, there was another aircraft flying above coming from the RIGHT (at angle of 30 to 135o). Traffic shown on IVSI was same per acft movement. After 1 second another ghost intruder with the same identification and altitude appeared at about 180o from the initial intruder at the same speed and disappeared once it enter the RA ring. We believed it was a reflection created by the MCD hinge.

Summary of Scenario 3
Moving the antenna forward did not solve completely the transient indication problem. Furthermore the fwd location cannot be used for antenna installation due to the 9G barrier attachments.

Scenario 4 – MCD hinge covered using a metal plate (5’X 3’). T-49C transmitting to the Upper ACAS II antenna. Carried out outside hangar.

12) Powered up with no signal from tester, same per described in Scenario 1 para (1).

13) T-49C transmits at 0º (about 5 meter) from Upper ACAS II Antenna
- Intruder (signal from T-49C) with correct direction and altitude was seen on IVSI.
- At the same time, acft taking off/landing from runway was also seen on IVSI.
- No nuisance image occurred.

14) T-49C transmits at 90º (about 5 meter) from Upper ACAS II Antenna
- Intruder (signal from T-49C) with correct direction and altitude was seen on IVSI. The correct intruder with the diamond shape (solid, white) changed to circle (Amber, solid) and aural warning (TA & RA) was audible once intruder entered the 2 mile range ring. This is correct indication.
- Nuisance intruder (Solid diamond shape) appeared at 315º + 1200 ft and disappeared after 1 second.
- At the same time there was a solid diamond at +1200 to +1300 ft and duplicated it self for a few seconds and disappeared.

15) T-49C transmits at 45º, 135º, 225º, 270º and 315º (about 5 meter) from Upper ACAS II Antenna
- T-49C ‘ON’. Intruder with correct direction and altitude was seen on IVSI
- No nuisance image occurred.

Summary of Scenario 4
Covering the MCD hinge with the metal plate removed the problem of duplicate image at opposite direction (at angles of 45 o, 90 o, and 135o). The correct intruder was shown on IVSI and provided a correct visual and aural warning. However, ghost (intruder with no ident i.e. direction and altitude) persisted when signal was at 90º; and the ghost indications were different to Scenario 1.



Summary/Discussion

1) Based on the findings above the system is considered operative except for the spurious signals that typically last few seconds. The system provides correct intruder identification and path, visual and aural warning. Blank diamond shape (white) changes to solid (white) and then once inside the 2 nm range ring, diamond shape changes to circle (Solid, Amber) and aural warning (TA and RA) are triggered.

2) All scenarios except 4 showed the reflected (nuisance) image of intruder once with simulated acft approaching at angles of 45, 90, and 135 degrees. The ghost intruder (TA diamond) disappeared once it entered 2 nm range ring.

3) Covering the MCD hinge with a metal plate (scenario 4) removed the problem of spurious duplicate image at opposite direction (at angles of 45, 90, and 135 degrees).

4) Moving the antenna forward did not solve the transient indication problem.

5) Nuisance intruder (no ident i.e. direction and altitude) appeared at all scenarios; but less when the MCD hinge was covered with metal plate.

6) The protruding MCD hinge has created reflected signals which caused transient indications of intruders.

7) There was no reply from other B737-200 freighter operators if they faced the same problem.

8) The most promising solution is covering the MCD hinge with some fairing; preferably metallic. However it would not eliminate completely spurious signals since simulated acft at 90 o caused nuisance indications.

9) Cause of transient indications during system start up is not identified; but the short duration does not cause a problem.

Conclusion

This problem of spurious and transient ACAS II indications is most probably caused by the protruding MCD hinge introduced by the freighter modification. However the ACAS II system is operative and providing correct warnings. Most promising solution is to install a metallic fairing over the MCD hinge and this will be pursued with AEI. However it would not eliminate all spurious signals. Educating the flight crew should prevent faulting the ACAS II system due to the spurious/transient indications described.

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