Airport Boarding & Check-In Step-by-Step Guide 2026: Complete Master Guide for First-Time Travelers
Departing on an international flight from Dhaka (HSIA), Chittagong (CTG), or Sylhet (ZYL) consists of 5 consecutive procedural clusters: 1. Terminal Curbside Entry (showing passport & ticket), 2. Airline Check-in & Luggage Drop (weighing bags & obtaining boarding pass), 3. Central Security Screening (X-ray trays & metal detector), 4. Immigration Police Desk & e-Gates (biometric document verification), and 5. Boarding Gate & Aircraft Seating (zone system & overhead bin storage). This guide covers every single step with complete operational clarity.
📑 Table of Contents: 5 Core Master Modules
1. Introduction: Overcoming Airport Anxiety & Mental Preparation
Traveling by air for the first time—especially for outbound migrant workers heading to the Middle East, Malaysia, or Europe—can feel overwhelming. The sight of armed security, automated glass gates, biometric scanners, and foreign airport staff often creates anxiety. Remember: every procedure is standardized, every queue moves logically, and airport personnel are there to assist you. With this guide, you will know exactly what to do at every corner of the terminal.
2. The Complete 7-Step Airport Journey Roadmap
- Terminal Curbside: Arrive 4 hours before departure, collect a free trolley, and show your passport and ticket to security at the gate.
- FIDS Screen: Look up your flight number to identify your airline's active check-in row.
- Check-In & Baggage Tagging: Weigh suitcases, hand over heavy bags, and receive your printed boarding pass.
- Security Screening: Sort electronics into plastic trays and walk through the metal detector.
- Immigration Passport Control: Present your passport, visa, and BMET card to the immigration police officer or use automated e-Gates.
- Departure Lounge: Wait near your designated boarding gate and listen for public boarding announcements.
- Aircraft Boarding: Walk through the aerobridge, enter the plane, stow your carry-on in the overhead bin, and buckle your seatbelt.
Cluster 1: Airport Arrival & Departure Terminal Entry (Steps 1 to 6)
1. Airport Reporting Time: 4 Hours Before Flight
International airlines close their check-in counters strictly 60 minutes before departure. Arriving 4 hours in advance gives you a safe buffer for Dhaka highway traffic, long entry queues, and security checks.
2. Departure Entry Gate Police Verification
Have your original passport and printed air ticket in hand before reaching the gate. Officers check that the name matches and that your flight departs within the next 4 to 6 hours.
3. Farewell Etiquette: Family Members Restricted Outside
Under international civil aviation safety rules, friends and relatives cannot enter the departure terminal. Bid farewell at the outside canopy area to avoid crowding the entry doorways.
4. Free Luggage Trolleys: Zero Tip Rights
All luggage trolleys at Bangladesh international airports are 100% free. Never pay tips or baksheesh to anyone claiming to manage trolleys.
5. Probashi Kalyan Helpdesk Support
First-time migrant workers facing confusion can consult the government Probashi Kalyan Desk located inside the concourse. Officers check BMET cards and guide you to your counter.
6. Curbside Vehicle Drop-off Regulations
Cars and microbuses may only stop in the drop-off lanes for 3 to 5 minutes to unload. If drivers leave cars unattended, airport traffic police tow them immediately.
Cluster 2: Airline Check-in Counter, Luggage Drop & Boarding Pass (Steps 7 to 12)
7. Reading FIDS Screens to Find Your Counter
Overhead Flight Information Display System (FIDS) monitors list flights alphabetically or by time. Identify your flight number (e.g. SV-805, EK-582, BG-339) to find your assigned check-in counter row.
8. Baggage Weight Limit: Max 32kg Per Piece
Place your large suitcases one by one on the digital scale conveyor. Ensure neither exceeds the ticket limit (usually 23kg or 30kg) and never exceeds 32kg under international labor safety rules.
9. Understanding Your Boarding Pass
Your boarding pass is your flight ticket. It shows your Seat Number (e.g., 34K), Boarding Gate (e.g., Gate 6), Boarding Time, and Sequence Number. Keep it inside your passport.
10. Luggage Tag Barcode Stickers
The agent attaches long barcode tags to your suitcases and sticks small claim stubs onto the back of your boarding pass. Never peel these off; they are required to claim lost baggage.
11. Requesting Window vs. Aisle Seats
Politely ask the check-in agent for a window seat ("Window please") or an aisle seat ("Aisle please"). Window seats offer outside views and wall resting; aisle seats give easy access to restrooms.
12. Online Web Check-in Advantages
Performing web check-in 24–48 hours before your flight lets you choose your favorite seat for free and drop bags at dedicated, fast-moving baggage drop desks.
Cluster 3: Security Scanning & Prohibited Items Check (Steps 13 to 18)
13. Plastic Tray Sorting Protocol
Place your laptop and power bank in Tray 1. Place phone, watch, belt, wallet, keys, and jacket in Tray 2. Place your cabin bag flat on the conveyor belt.
14. Power Bank Regulations (Max 100Wh / 20,000mAh)
Power banks must ALWAYS be carried in cabin hand luggage. Packing power banks in checked suitcases is an aviation crime due to fire risk in cargo holds.
15. 100ml Liquid Limit (LAGs Rule)
Liquid containers in hand luggage cannot exceed 100 ml each. All bottles must fit in a 1-liter transparent plastic pouch. Larger mustard oil, honey, or perfume bottles must be checked in.
16. Prohibited Cabin Sharp Objects
Blades, scissors, nail clippers, pocket knives, and screwdrivers are strictly prohibited in the cabin. Pack them inside your large checked luggage.
17. Prescription Medicine Rules
Carry daily medication (blood pressure, diabetes, insulin) in hand luggage with an original doctor's prescription in English matching the name on your passport.
18. Free Drinking Water & Duty-Free Past Security
Once through security, free water refill fountains and duty-free shops are available. You can carry an empty water bottle through security and refill it in the waiting area.
Cluster 4: Immigration Police Desk, e-Gates & Document Verification (Steps 19 to 24)
19. Immigration Desk Questions & Confident Answers
Officers ask simple verification questions: your destination, company name, profession, and return plans. Maintain calm eye contact and give direct, truthful answers matching your visa papers.
20. Correct Presentation File Sequence
Arrange documents in this exact order: 1. Passport, 2. Boarding Pass, 3. Printed Visa, 4. BMET Smart Card, and 5. Medical Certificate. Hand them over together in a transparent folder.
21. Automated e-Gates for e-Passport Holders
Scan the passport photo page face-down. Enter the booth, look at the camera for facial recognition, and place your right index finger on the biometric scanner. The exit gate opens in 15 seconds.
22. Fingerprint Mismatch Solutions
If fingers are sweaty or dry, biometric scanners may fail. Clean your fingertips on your shirt or ask for a wet wipe. Officers have supervisor override terminals to verify records manually.
23. Minimum 6-Month Passport Validity
International law mandates at least 6 months of validity on your passport from your travel date. If less than 6 months remain, immigration systems will automatically block departure.
24. Verifying the Departure Exit Stamp
Before walking away from the immigration booth, check that the officer stamped an ink exit seal on your passport page showing today's date. A missing exit stamp causes legal issues upon your return.
Cluster 5: Boarding Gate, Zone System & Aircraft Entry (Steps 25 to 30)
25. Finding Your Boarding Gate via Signage
Follow the large illuminated yellow ceiling signs showing Gate Numbers (e.g. Gates 1–10 to the left, 11–20 to the right). Recheck FIDS screens to ensure the gate hasn't changed.
26. Boarding Gate Timings & Final Call
Be seated at the gate area 45 minutes before departure. Gate boarding begins 40 minutes before flight time and closes 15 minutes before takeoff. Never wander off for shopping during final calls.
27. Zone Boarding System (Zone 1/2/3) Etiquette
Airlines call passengers in zones. When your zone is called, form an orderly queue with your passport and boarding pass open.
28. Lost Boarding Pass Solutions
If you misplace your boarding pass inside the departure lounge, approach your gate staff immediately. They can reprint a duplicate pass using your passport in 2 minutes.
29. Overhead Bin Storage Etiquette
Place your wheeled cabin bag into the overhead bin wheels-first. Place small backpacks under the seat in front of you so others have room for their bags.
30. Destination Arrival & Passport Border Number
Upon landing in Saudi Arabia or Gulf hubs, immigration officers write a 10-digit Border Number in your passport. Keep this safe; your employer needs it to process your Iqama.
8. Comparative Analysis of Leading Airlines' Check-in & Baggage Policies
| Airline Name | Economy Checked Baggage | Cabin Handbag | Web Check-in Window | Counter Closing Time |
|---|---|---|---|---|
| Biman Bangladesh | 2 x 23 kg (or 30 kg total) | 7 kg | 24 hours prior | 60 mins before departure |
| Saudia (SV) | 2 x 23 kg (Guest Class) | 7 kg + laptop bag | 48 hours prior | 60 mins before departure |
| Emirates (EK) | 25 kg – 35 kg (weight concept) | 7 kg | 48 hours prior | 60 mins before departure |
| Qatar Airways (QR) | 25 kg – 35 kg (or 2 x 23 kg) | 7 kg | 48 hours prior | 60 mins before departure |
| Air Arabia (G9) | 20 kg – 30 kg (pre-booked) | 10 kg (strict size) | 36 hours prior | 60 mins before departure |
| Flydubai (FZ) | 20 kg – 30 kg (as per fare) | 7 kg | 48 hours prior | 60 mins before departure |
| Kuwait Airways (KU) | 2 x 23 kg | 7 kg | 24 hours prior | 60 mins before departure |
| Gulf Air (GF) | 2 x 23 kg (Falcon Economy) | 6 kg | 24 hours prior | 60 mins before departure |
🏆 9. 10 Golden Rules & Emergency Checklist for Expatriate Workers
🔗 Related Essential Travel Guides & Resources:
❓ 10. 30 High-Search Airport Queries & Expatriate Solutions (FAQ)
1. Exactly how many hours before scheduled flight departure should I reach the airport? ▼
For international flights, you must arrive at the airport terminal at least 4 hours before your scheduled departure. This ensures ample time to clear curbside security, locate your check-in counter, complete luggage drop, undergo central security X-ray screening, and clear immigration passport control without missing your boarding call.
2. What documents must I show to the police at the airport terminal entrance gate? ▼
At the departure entrance gate, present two essential documents to the on-duty Armed Police Battalion (APBn) or Ansar officers: 1. Your original international passport booklet, and 2. A printed copy of your confirmed airline e-ticket or mobile flight itinerary showing today's date.
3. Can family members or relatives enter inside the departure terminal building? ▼
No. Under international civil aviation security regulations, only ticketed passengers traveling on flights scheduled within the next 4 to 6 hours are permitted inside the departure terminal building. Accompanying family members must bid farewell outside at the designated canopy concourse.
4. Is there any fee or charge for using luggage trolleys at Dhaka Airport? ▼
No. Luggage trolleys at Hazrat Shahjalal International Airport (HSIA), Chittagong (CTG), and Sylhet (ZYL) are 100% free of charge. You do not need coins, tokens, or cards. Demanding tips or fees is illegal; report anyone asking for baksheesh to the on-duty Executive Magistrate.
5. What assistance do first-time migrant workers receive from the Probashi Kalyan Desk? ▼
The government Probashi Kalyan Desk, located near the entrance gates, assists first-time outbound workers by reviewing BMET smart card registrations, verifying visa documentation, directing passengers to correct check-in counters, and providing general travel counseling.
6. How long can passenger drop-off vehicles stop at the terminal kerbside lane? ▼
Vehicles dropping off passengers at the departure concourse are restricted to a maximum stay of 3 to 5 minutes strictly for unloading luggage and passengers. Unattended vehicles or long parking in drop-off lanes results in immediate towing and heavy fines by airport traffic police.
7. How do I find my airline's check-in counter using the FIDS screens? ▼
Look at the large Flight Information Display System (FIDS) overhead screens in the departure hall. Find your flight number (e.g., BG-339, SV-805, EK-582) listed alongside your destination city. The screen will display your airline's active check-in row letter and counter numbers (e.g., Row C, Counters 1–12).
8. What is the maximum weight limit for an individual checked suitcase at check-in? ▼
Under international aviation labor safety standards, no single piece of checked luggage may exceed 32 kg (70 lbs), even if you purchase excess baggage allowance. Any bag heavier than 32 kg must be repacked into two separate suitcases to protect airport baggage handlers.
9. What is a boarding pass and what critical information does it contain? ▼
A boarding pass is your official flight admission boarding card issued at the check-in desk. It displays your Full Name, Flight Number, Departure Date, Assigned Seat Number (e.g., 28A), Boarding Gate Number (e.g., Gate 5), Boarding Time (usually 45 minutes before departure), and Boarding Group/Zone.
10. Why is the baggage claim tag sticker attached to the back of your boarding pass so important? ▼
The barcode sticker attached to the back of your boarding pass contains your unique luggage tracking number. If your suitcase is delayed or misplaced upon arrival, this barcode is mandatory for customs and airline ground staff to locate and deliver your luggage.
11. How can I request a window or aisle seat at the check-in counter? ▼
When handing your passport to the check-in agent, politely state your preference: 'Could I please have a window seat (or aisle seat) if available?' Alternatively, select your preferred seat online 24 to 48 hours prior to departure during web check-in on the airline's website.
12. What are the advantages of completing online web check-in before going to the airport? ▼
Web check-in allows you to choose your seat for free, download a mobile boarding pass, and skip the regular check-in queues by dropping your bags at the dedicated 'Baggage Drop' counter in under 5 minutes.
13. What items must be removed and placed into separate plastic trays during security scanning? ▼
You must empty your pockets of all metallic items: mobile phones, coins, wallets, keys, wristwatches, heavy belts, and jackets into Tray 1. Laptops, tablets, and power banks must be removed from your backpack and placed in Tray 2.
14. Which bag should power banks be packed in, and what is the maximum allowed capacity? ▼
Power banks must ALWAYS be carried in your cabin hand luggage; they are strictly prohibited in checked baggage. The maximum allowed capacity is 100 watt-hours (Wh) (roughly 20,000–27,000 mAh). Power banks exceeding 160Wh are banned completely.
15. How much liquid, lotion, or oil can be carried in cabin hand luggage? ▼
Under the international LAGs rule, liquids, gels, sprays, and lotions must be in containers of maximum 100 ml (3.4 oz) each, packed inside a single transparent, resealable 1-liter plastic bag. Larger containers must be packed in checked suitcases.
16. In which bag should nail clippers, shaving razor blades, and scissors be packed? ▼
All sharp objects, including nail clippers with fold-out files, safety razor blades, knives, and scissors, must be packed in checked luggage. They will be confiscated immediately if detected in cabin hand baggage.
17. Is a medical prescription mandatory for carrying daily prescription medications? ▼
Yes. Carrying vital prescription medicines (e.g., insulin, blood pressure pills, asthma inhalers) in hand baggage requires a doctor's valid prescription written in English matching the passenger's name on their passport.
18. Where can I get clean drinking water after passing security screening? ▼
Once through security, free filtered drinking water dispensers (hot and cold) are available throughout the boarding concourses near boarding gates and restrooms. You can bring an empty water bottle through security and refill it past the checkpoint.
19. What questions do immigration police officers ask migrant workers at the desk? ▼
Common questions include: 'Where are you traveling?', 'What company or sponsor will you work for?', 'What is your job role?', and 'Have you completed your BMET registration?' Answer calmly and honestly matching the details on your employment visa.
20. What is the correct file sequence for presenting documents at immigration counters? ▼
Arrange documents in a clear transparent folder in this exact order: 1. Original Passport booklet opened to the photo page, 2. Boarding Pass, 3. Printed Official Employment Visa / eVisa, 4. BMET Smart Card / Clearance Certificate, and 5. Medical Fitness Fit Card.
21. How do Bangladeshi e-Passport holders use the automated e-Gates at Dhaka Airport? ▼
1. Place the biometric photo page of your e-passport face-down on the glass reader. 2. When the first glass door opens, step inside and look directly into the camera for facial recognition. 3. Place your right index finger on the biometric glass scanner; the exit gate will open automatically in 15 seconds.
22. What should I do if my fingerprint or biometric scan does not match at immigration? ▼
Do not panic. Wash and dry your hands thoroughly or ask the officer for a hand sanitizing wipe. If the electronic reader still fails to match, the supervisor will manually verify your passport and BMET biometrics against the central immigration server.
23. What is the minimum passport validity required to pass international airport immigration? ▼
Your passport must have at least 6 months of validity remaining from your travel date. If your passport has less than 6 months of validity, immigration authorities will deny boarding and offload you.
24. Why must you check the departure exit stamp in your passport before walking away? ▼
Ensure the immigration officer clearly stamped your passport with today's date and departure exit mark. Missing an exit stamp can lead to severe fines, deportation, or re-entry bans when renewing visas or returning home.
25. How do I find my boarding gate number inside the airport departure lounge? ▼
Check your boarding pass for the initial gate number, then verify it on the overhead FIDS flight screens in the departure lounge. Follow the large yellow directional hanging signs pointing to Gates 1–15.
26. How long before flight departure must I be present at the boarding gate? ▼
You should be seated near your boarding gate at least 45 minutes to 1 hour before departure. Boarding gates close strictly 15 to 20 minutes before takeoff; arriving after gate closure results in being offloaded without compensation.
27. What does the Zone number (Zone 1 / 2 / 3) printed on the boarding pass mean? ▼
Airlines board passengers in stages to avoid cabin aisle bottlenecks. Zone 1 includes business class and rear-row window seats; Zone 2 includes middle rows; Zone 3 includes front economy rows. Wait until your specific Zone number is called over the public address system.
28. What should you do if you lose your boarding pass inside the airport after immigration? ▼
Walk immediately to your airline's departure boarding gate desk or customer service counter. Show your original passport; the gate agent can verify your ticket manifest and print a duplicate boarding pass within 2 minutes.
29. What is the proper etiquette for stowing cabin bags in overhead airplane bins? ▼
Place your roller trolley suitcase wheels-first or flat into the overhead bin directly above your assigned seat row. Place your smaller personal backpack or handbag underneath the seat in front of you so fellow passengers have bin space.
30. What is the Border Number stamped on your passport upon landing in Gulf countries? ▼
When landing in Saudi Arabia, UAE, or Qatar, the destination immigration officer writes or stamps an official 10-digit Border Number (Raqam al-Hudud) on your visa page. This number is mandatory for your employer to process your legal Iqama residency card and opening bank accounts.
11. Conclusion: Have a Safe & Dignified Journey Abroad
Millions of brave Bangladeshi expatriate workers power our national economy. Understanding every step of the airport process empowers you to travel with confidence and dignity. For live flight status, currency rates, and aviation rules, keep the Probashi Flight Guide bookmarked on your phone.
Comprehensive Check-In Queue Management & Flight Manifest Verification
Airline check-in operations at Hazrat Shahjalal International Airport in Dhaka function under strict International Civil Aviation Organization (ICAO) and IATA Annex 9 standards. Ground handling agents representing international carriers must cross-verify passenger identities across three distinct operational layers before generating boarding documents:
1. Advance Passenger Information System (APIS) Electronic Transmission
As soon as your passport is swiped through the optical counter scanner, the airline DCS (Departure Control System) transmits your bio-data, passport validity, nationality, and visa details to the destination country's border authority (e.g., US CBP, UK Home Office, Saudi MOI, or Malaysian Immigration). An electronic 'Board / No Board' directive is returned automatically in real time. If the receiving country flags a security restriction, the agent's screen locks, requiring supervisory clearance.
2. Baggage Weight Balancing & Aircraft Trim Sheet Calculations
Every checked suitcase weighed on the counter scale transmits numeric data to the airport's Central Load Planning office. Loadmasters calculate the aircraft's Center of Gravity (CG) and zero-fuel weight to balance cargo distribution between forward, aft, and bulk cargo compartments. Inaccurate luggage weights jeopardize aircraft pitch stability during takeoff rotation, which is why check-in agents strictly enforce baggage thresholds and reject overweight individual bags exceeding the 32kg occupational health maximum.
3. Boarding Gate Security & Final Headcount Procedures
At the boarding gate, airline agents perform a final physical reconciliation between the electronic passenger manifest and the scanned boarding pass stubs. If a checked-in passenger fails to board the aircraft by the final call (strictly 15 to 20 minutes prior to scheduled departure), international aviation anti-terror legislation mandates that the passenger's checked bags must be offloaded from the cargo hold before the aircraft is granted pushback clearance. This process, known as positive passenger baggage reconciliation, ensures that an aircraft never departs with unescorted baggage.
4. Special Passenger Categories: Unaccompanied Minors, Stretchers & Wheelchairs
Special assistance requests require specialized check-in handling. Unaccompanied Minors (children aged 5 to 11 traveling alone) receive a distinctive wearable pouch containing their passport, ticket, and parental release documentation, accompanied continuously by designated airline ground escort staff. Passengers requiring medical oxygen or stretcher transport must check in at least 4 hours early with pre-approved MEDIF forms, while wheelchair passengers are assisted by dedicated attendants directly to aircraft seat doors.
Comprehensive Check-In Queue Management & Flight Manifest Verification
Airline check-in operations at Hazrat Shahjalal International Airport in Dhaka function under strict International Civil Aviation Organization (ICAO) and IATA Annex 9 standards. Ground handling agents representing international carriers must cross-verify passenger identities across three distinct operational layers before generating boarding documents:
1. Advance Passenger Information System (APIS) Electronic Transmission
As soon as your passport is swiped through the optical counter scanner, the airline DCS (Departure Control System) transmits your bio-data, passport validity, nationality, and visa details to the destination country's border authority (e.g., US CBP, UK Home Office, Saudi MOI, or Malaysian Immigration). An electronic 'Board / No Board' directive is returned automatically in real time. If the receiving country flags a security restriction, the agent's screen locks, requiring supervisory clearance.
2. Baggage Weight Balancing & Aircraft Trim Sheet Calculations
Every checked suitcase weighed on the counter scale transmits numeric data to the airport's Central Load Planning office. Loadmasters calculate the aircraft's Center of Gravity (CG) and zero-fuel weight to balance cargo distribution between forward, aft, and bulk cargo compartments. Inaccurate luggage weights jeopardize aircraft pitch stability during takeoff rotation, which is why check-in agents strictly enforce baggage thresholds and reject overweight individual bags exceeding the 32kg occupational health maximum.
3. Boarding Gate Security & Final Headcount Procedures
At the boarding gate, airline agents perform a final physical reconciliation between the electronic passenger manifest and the scanned boarding pass stubs. If a checked-in passenger fails to board the aircraft by the final call (strictly 15 to 20 minutes prior to scheduled departure), international aviation anti-terror legislation mandates that the passenger's checked bags must be offloaded from the cargo hold before the aircraft is granted pushback clearance. This process, known as positive passenger baggage reconciliation, ensures that an aircraft never departs with unescorted baggage.
4. Special Passenger Categories: Unaccompanied Minors, Stretchers & Wheelchairs
Special assistance requests require specialized check-in handling. Unaccompanied Minors (children aged 5 to 11 traveling alone) receive a distinctive wearable pouch containing their passport, ticket, and parental release documentation, accompanied continuously by designated airline ground escort staff. Passengers requiring medical oxygen or stretcher transport must check in at least 4 hours early with pre-approved MEDIF forms, while wheelchair passengers are assisted by dedicated attendants directly to aircraft seat doors.
Comprehensive Airport Ground Handling: Security Screening, E-Gates & Boarding Zone Management
Navigating modern international airport terminals demands an in-depth understanding of airport layout architecture, passenger sequence processing, and digital boarding pass authentication. At bustling transit hubs like Dhaka Hazrat Shahjalal International Airport (DAC), Dubai International (DXB), and Singapore Changi (SIN), passenger throughput is organized into rigid chronological phases designed to maintain strict civil aviation safety while accommodating thousands of travelers per hour.
Phase 1: Terminal Entry & Kiosk Check-In
Show your valid passport and printed e-ticket confirmation to the security guard at terminal entry doors. Proceed directly to the self-service check-in kiosks if traveling without checked baggage, or join your airline's designated check-in row. Keep baggage tags safely attached to your boarding pass slip.
Phase 2: Emigration & Biometric E-Gates
Present your e-Passport at the automated e-Gates or standard immigration counter. Remove eyeglasses, caps, and face masks for facial biometric camera scanning. Place your thumb or index finger firmly on the optical biometric reader until the indicator light illuminates green.
Phase 3: Security Archway & Hand Baggage X-Ray
Remove laptops, tablets, power banks, and transparent liquid bags from your carry-on luggage and place them in separate plastic scanning bins. Empty pockets of metal items, coins, belts, and mobile devices before walking through the millimeter-wave body scanner.
Phase 4: Gate Waiting & Boarding Group Calls
Airlines board passengers by designated seating zones or groups (e.g., Group 1 for First/Business, Group 2 for rear cabin economy, Group 3 for mid cabin). Remain seated until your boarding group number is explicitly announced over the gate public address system to prevent unnecessary gate congestion.