Desert Operation Guidelines
Effectivity: BD-700-2A12 aircraft
Infoservice
Aircraft operating in desert regions are exposed to air that carries a high concentration of dust, seasonally combined with extreme heat and, in coastal areas, a high humidity.
Other than the exposure on the ground, dust from desert sand and construction sites is also carried to altitude by strong winds and sandstorms.
Ingestion of dust and sand will typically degrade components in the engines, air conditioning and pressurization systems, while the high temperatures affect engine performance and electronic components.
Whilst the Environmental Corrosion Control and Prevention Guidelines address corrosion, exposure to sand, dust and extreme heat will also require special attention for a number of components and systems.
This publication is a compilation of references and information, to be used as a helpful guide for maintenance departments developing customized maintenance practices when operating in desert regions and other areas with a high concentration of airborne pollutants.
FCOM Supplement 07B-13 provides operational guidance.
Information published in this Infoservice is considered accurate. However, the data published in our manuals takes precedence at all times.
This document is subject to revision, and it is always recommended to obtain the latest version from the Bombardier online portal, whenever referenced.
Revision status of the tasks presented are controlled within their respective publications. Any such revisions are not automatically updated in this document.
Initial release
ATA 10 - Parking
AMP Task
Task: BD700-A-J10-12-00-00AAA-720A-A
Subject: Installation of the Covers and Plugs
Benefits:
Covers and plugs will prevent sand and dust ingress in critical areas.
Whenever parking on the ramp in desert region airports and airfields, whether short- or long-term, it’s important to protect the aircraft against the elements. In particular, the use of engine covers is critical to prevent dust contamination of the internal cooling as well as erosion and sand build-up.
If parked for longer periods, the external windshield cover will help provide protection from the sunlight and small particle impact caused by strong winds and jet blast. It’ll also help prevent erosion of the aerodynamic seals.
Note: During short-term parking, in case it’s not possible to install the engine covers, it’s recommended to inspect and dry motor the engines for at least 2 minutes prior to flight. For any long-term parking, engine covers must be used.
MPD Reference
Task:BD700-3AB48-11500-00 section 15
Subject: Walk Around Inspection
Benefits:
Increase dispatch availability. Regular walk around inspections carried out by a technician, who will also be able to carry out any servicing required, will help maintain operational readiness.
Note: With no scheduled flights or general maintenance planned for up to 7 days, Short-term parking is applicable (AMP BD700-A-J10-10-02-00AAA-170A-A).
And if parked for more than 7 consecutive days, the Long-term procedure is applicable(AMP BD700-A-J10-10-03-00AAA-170A-A).
Precaution
ATA: 21-53-03
Subject: Pre-flight precaution
Benefits:
Prior to departure, it’s recommended to carry out a FOD inspection of LH and RH dual heat exchangers through the diffuser inspection windows.
ATA 12 - Servicing
AMP Tasks
Task: BD700-A-J12-21-00-03AAA-251A-A
Subject: Windshields and side windows - Cleaning
Benefits:
Regular cleaning of the windshield and side windows including the weather- and hump seal, will help prevent FOD and maintain the seal integrity, preventing moisture and sand ingress.
Task: BD700-A-J12-21-00-04AAA-251A-A
Subject: External surfaces of the aircraft - Cleaning
Benefits:
Cleaning the aircraft’s external surfaces regularly prevents the accumulation of sand and dust, mitigating corrosion, contamination and degradation.
Desert Operation Task Intervals
BD-700-2A12
Note:
*Applicability: MSN 70214-70300 and all aircraft with SB 700-31-7505 embodied.
* Threshold: 1700 H / 23 C margin loss, Interval: 1700 H / 15 C,
GE SB 71-00-0000-00A-930A-D refers.
*** Wash frequency is also depending on engine trend and to be determined by the operator.
ATA 21 - Environmental control
AMP Tasks
Task: BD700-A-J21-21-11-00AAA-921A-A
Subject: Recirculation filter - Discard
Benefits:
The recirculation filter assembly contains a high-efficiency particulate air (HEPA) filter capable of removing more than 99% of particles larger than 3 microns. Replacement of the filter assembly is currently scheduled at 1700 H.
For aircraft frequently operating in desert regions, replacing it earlier will help maintain clean cabin air.
Task: BD700-A-J21-52-01-00AAA-258A-A
Subject: Plenum - Other procedure to clean
Benefits:
The inlet plenum collects the ram airflow leaving the dual heat exchanger and the APS heat exchanger. Any contaminants not exiting the ram air exhaust, will gradually accumulate and build up around the ACM fan. Scheduled regular cleaning of the inlet plenum will help mitigate degradation of the ACM fan.
Task: BD700-A-J21-52-05-00AAA-258A-A
Subject: Dual heat exchangers - Other procedure to clean
Benefits:
Exposed directly to the elements, the dual heat exchanger is vulnerable to FOD and particle ingestion. Sand, dust and other airborne pollutants will gradually accumulate in the heat exchanger, restricting the airflow and heat transfer. Scheduled regular cleaning of the dual heat exchanger will help ensure consistent bleed air cooling.
ATA 21 - Environmental control
AMP Tasks
Task: BD700-A-J21-52-07-00AAA-258A-A
Subject: Condenser/reheater unit - Other procedure to clean
Benefits:
Bleed air impurities and solid particles will gradually accumulate in the condenser/ reheater unit, restricting the airflow and transfer of hot bleed air to the ACM turbine in- and outlet. Scheduled regular cleaning of the condenser/reheater unit will help prevent damage to the ACM and maintain its ability to provide consistent cooling.
Task: BD700-A-J21-52-09-00AAA-258A-A
Subject: Water extractors - Other procedure to clean
Benefits:
When impurities and solid particles mix with the water extracted from the air exiting the condenser, it will turn into mud with the risk of clogging the overboard drain and water injector lines. Scheduled regular cleaning of the water extractor, including the injector and drain lines, will ensure unrestricted flow of the extracted water and help prevent contamination of the condenser/reheater.
Task: BD700-A-J21-54-11-00AAA-921A-A
Subject: Forward avionics-rack filter - Discard
Benefits:
A filter is preventing dust contamination of the avionics and electrical equipment in the forward avionics rack. Replacement of this filter is currently scheduled at 1700 H. For aircraft frequently operating in areas with a high concentration of dust, replacing it earlier will help mitigate equipment failure.
ATA 21 - Environmental control
AMP Tasks
Task: BD700-A-J21-62-07-00AAA-258A-A
Subject: Air Preparation System heat exchanger - Other procedure to clean
Benefits:
Exposed directly to the elements, the APS heat exchanger is vulnerable to FOD and particle ingestion. Sand, dust and other airborne pollutants will gradually accumulate in the heat exchanger, restricting airflow and heat transfer. Scheduled regular cleaning of the APS heat exchanger will help ensure cool air supply to the OBIGGS Package.
Precaution
ATA: 21-60-23
Subject: High OAT precaution - aft equipment- compartment
Benefits:
Two fans and a dual channel temperature sensor are installed in the aft equipment- compartment to protect the APU FADEC, RADALT transceivers and other equipment. Operating in active/standby mode, the active fan starts when the SAT is greater than 30°C (86°F). If the temperature exceeds 68°C (154°F) for more than 30 seconds, an AFT BAY OVHT caution message is posted on EICAS, preventing dispatch.
If the APU is supplying bleed air to the ECS for extended periods at peak temperatures during the summer, the fan is unable to cool adequately and the aft bay temperature will eventually exceed 68°C (154°F).
As per FCOM Vol. 1 02-05-12, APU bleed air extraction on ground for ECS operation is limited to 48 °C OAT. This limit will help prevent an overtemp shut down of the APU FADEC. In case the AFT BAY OVHT caution message is posted, the aft equipment compartment will need to be cooled. Opening the access door should bring down the temperature; however, if insufficient, an external cooling source will be needed. The CAS message is removed once the temperature is below 68°C. The temperature can be monitored via the OMS.
ATA 31 - Indicating/recording systems
AMP Tasks
ATA: BD700-A-J31-61-05-03AAA-921A-A
Subject: Adaptive Flight Display inside and outside fan filters - Discard
Benefits:
To prevent dust accumulating and eventually failing the AFDs, filters have been introduced in the Adaptive Flight Display Trays. Scheduled regular replacement of the AFD filters will help ensure adequate cooling/airflow and prevent dust contamination.
Note: The inside and outside AFD filters have been introduced in production with a cut-in at MSN 70214 and via SB 700-31-7505 for MSN 70006-70213.
ATA 36 - Pneumatic
AMP Tasks
ATA: BD700-A-J36-11-09-00AAA-258A-A
Subject: ECS pre-cooler - Other procedure to clean
Benefits:
Exposed directly to the elements whenever the ram air door is open, the ECS precooler is vulnerable to FOD and particle ingestion. Sand, dust and other airborne pollutants will gradually accumulate in the precooler, restricting the airflow and heat transfer. Scheduled regular cleaning of the ECS precooler will help ensure cool air supply to the ECS and APS.
ATA: BD700-A-J36-11-17-00AAA-258A-A
Subject: Main pre-cooler - Other procedure to clean
Benefits:
Sand, dust and other airborne pollutants contained in the fan air will gradually accumulate in the precooler, restricting the airflow and heat transfer. Scheduled regular cleaning of the main precooler will help ensure bleed air cooling.
ATA 49 - Airborne auxiliary power
AMP Tasks
ATA: BD700-A-J49-10-01-00AAA-258A-A
Subject: Airborne auxiliary-power-unit - Other procedure to clean
Benefits:
Sand, dust and other airborne pollutants will gradually accumulate in the APU compressor. Scheduled regular wash of the APU compressor impeller will help reduce degradation, mitigating loss of performance in the compressor section.
ATA 71 - Power plant
AMP Tasks
ATA: BD700-A-J71-00-00-03AAA-398A-A
Subject: Engine Wash - with chemical agent or water only
Benefits:
For aircraft parked on the ramp in desert region airports and airfields, diligent use of engine covers will greatly reduce the adverse effects of particle erosion and contamination. However, when flying, particularly at low altitude, ingestion of dust and other airborne pollutants cannot be avoided.
Washing the engines regularly will help prevent build-up of particles blocking the internal cooling, thus mitigating degradation and loss of ITT margin.
Note: It’s recommended to dry motor the engines for at least 2 minutes prior to washing. In case the aircraft has been exposed to severe dust and sand conditions, the following procedure applies: LMM - GEK112062 Task 72-00-00-02B-310A-D.
Maintenance & Operational Guidance
Task: AMP tasks G FCOM Supplement referenced in this document Engine longevity
Subject: Engine cleanliness and ITT management are the two main drivers to help preserve engine life.
Benefits:
Keeping the engines clean is accomplished with the use of covers and/or a hangar, dry motoring, and washing.
Maintaining a healthy ITT margin when operating in areas with extreme seasonal heat, requires special consideration with respect to thrust settings. During periods with elevated temperatures, at takeoff, it’s recommended to use the maximum assumed temperature thrust reduction that meets performance requirements.
Final Thoughts
The recommended tasks coincide with existing MRBR inspection intervals, keeping the operational inconvenience to a minimum. However, depending on the operation, it might be more beneficial to carry out some of these tasks seasonally – for example, before the summer heat.
Ultimately, it’s at the discretion of the operator to compile a program tailored to the operational environment. Along with the regulatory requirements, the MRBR always takes precedence.
Infoservice
Desert Operation Guidelines BD-700-2A12 aircraft
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