What is IATA IMP?
The IATA Interchange Message Procedures (IMP) is a standardised messaging framework developed by the International Air Transport Association (IATA) to enable electronic data interchange between airlines, freight forwarders, ground handling agents, and other parties in the air cargo supply chain.
IMP defines the format, structure, and content of messages exchanged between these parties. Type B messages are the core operational messages — plain-text, line-based telegraphic messages transmitted over SITA/ARINC networks or modern IP-based equivalents. Despite being decades old, Type B messages remain the backbone of air cargo communication worldwide, processed by millions of shipments every day.
Type B refers to the SITA network message type. These are plain ASCII text messages with a strict line-by-line structure. They are lightweight, universally supported, and deeply embedded in airline and GHA systems globally. While XML-based Cargo-XML (CIMP) is the modern successor, Type B IMP remains widely used and understanding it is essential for anyone building or integrating air cargo systems.
Message Structure
Every IMP Type B message follows a strict hierarchical structure. Understanding this structure is the foundation for parsing, generating, or validating any cargo message.
-- Transmission Header -- .DESTINATION ORIGINATOR Line 1: Address line DDHHMM Line 2: Date/time (UTC) -- Message Header -- MSG-TYPE/VERSION e.g. FWB/16 -- Data Segments -- AWB-ORIGIN/AWB-NUMBER SEGMENT-ID/DATA-FIELDS ... -- Message End -- ZZZZ End-of-message indicator
Key Structural Rules
- Each line begins with a segment identifier (e.g. SHP, CVD, NME) followed by a forward slash and data fields
- Fields within a segment are separated by forward slashes (/)
- Lines are terminated with CR+LF
- Maximum line length is 69 characters for SITA Type B transmission
- The message ends with ZZZZ on its own line
- Dates use DDMMMYY format (e.g. 15MAR25) and times use HHMM in UTC
Core Message Types
The IMP standard defines over 30 message types covering the full lifecycle of a cargo shipment. Below are the most critical ones used in day-to-day operations.
FFR — Freight Booking Request
The FFR (Freight Booking Request) is sent by a freight forwarder or shipper to an airline's cargo reservation system to request space on a specific flight. It is the starting point of the cargo booking lifecycle.
Forwarder sends FFR → Airline responds with FBR (Booking Response) confirming or proposing an alternative → Forwarder acknowledges → AWB created and FWB transmitted.
Key FFR Segments
| Segment | Description | Example |
|---|---|---|
| FFR | Message identifier and version | FFR/3 |
| BKG | Booking details — flight, date, origin, destination | BKG/EK/521/15MAR25/DXB/LHR |
| SHP | Shipper details — name and address | SHP/ACME ELECTRONICS LLC/DUBAI |
| CNE | Consignee details | CNE/GLOBAL IMPORTS LTD/LONDON |
| CVD | Commodity and volume data — weight, pieces, dimensions | CVD/K/500/5/120/80/100 |
| SRI | Special handling requirements | SRI/ELI |
.EKDXBXH FWDDXBAA 150830 FFR/3 BKG/EK/521/15MAR25/DXB/LHR SHP/ACME ELECTRONICS LLC JEBEL ALI FREE ZONE/DUBAI/AE CNE/GLOBAL IMPORTS LTD UNIT 5 HEATHROW LOGISTICS PARK/LONDON/GB CVD/K/500.0/5/120/80/100 SRI/ELI NME/CONSUMER ELECTRONICS ZZZZ
FWB — Air Waybill Data Message
The FWB (Freight Waybill) is one of the most important messages in air cargo. It is the electronic master air waybill — a legally binding document that travels with the shipment and contains the complete contractual and operational details of the consignment.
FWB is transmitted from the freight forwarder or origin station to the airline, and then forwarded to all transit and destination stations. It is the primary data source for customs, handling agents, and consignees.
FWB Segment Structure
| Segment | Description | Example |
|---|---|---|
| FWB | Message type and version number | FWB/16 |
| AWB | Airway Bill number — airline prefix and serial | AWB/176-12345678 |
| ORG | Origin station and airline IATA code | ORG/DXB/EK/FWDDXBAA/T |
| SHP | Shipper name, address, city, country | SHP/ACME ELECTRONICS LLC/DUBAI/AE |
| CNE | Consignee name, address, city, country | CNE/GLOBAL IMPORTS LTD/LONDON/GB |
| AGT | Agent details — IATA agent code and name | AGT/12345678/FREIGHT WORLD DXB |
| RTG | Routing — flight and destination sequence | RTG/EK521/LHR |
| CVD | Commodity and volume — weight, pieces, dimensions | CVD/K/500.0/5/120/80/100/CM |
| NME | Nature of goods description | NME/CONSUMER ELECTRONICS |
| CHG | Charge details — rate class, charges | CHG/Q/500.0/3.50/1750.00 |
| SRI | Special handling codes | SRI/ELI/PER |
| OSI | Other service information | OSI/HANDLE WITH CARE |
.LHREKXH FWDDXBAA 150845 FWB/16 AWB/176-12345678 ORG/DXB/EK/FWDDXBAA/T/15MAR25 SHP/ACME ELECTRONICS LLC JEBEL ALI FREE ZONE GATE 5 DUBAI/AE/TEL/97143456789 CNE/GLOBAL IMPORTS LTD UNIT 5 HEATHROW LOGISTICS PARK LONDON/GB/TEL/442081234567 AGT/12345678/FREIGHT WORLD DXB RTG/EK521/LHR/EK CVD/K/500.0/5/120/80/100/CM NME/CONSUMER ELECTRONICS CHG/Q/500.0/3.50/1750.00/PP SRI/ELI OSI/DO NOT STACK ZZZZ
FHL — House Waybill Data Message
The FHL (Freight House Label) message carries the house waybill details for consolidated shipments. When a forwarder consolidates multiple smaller shipments under a single master AWB, each individual shipment is represented by a house waybill. The FHL transmits these house details to the airline and destination.
FHL messages are always associated with a parent FWB and reference the master AWB number. A single master AWB can have many associated FHL messages — one per house shipment.
1 FWB (Master AWB) contains the consolidated totals → linked to N × FHL messages, one per house waybill. Customs and destination handlers need both the FWB and all FHL messages to process the shipment.
.LHREKXH FWDDXBAA 150900 FHL/5 AWB/176-12345678 MWB/176-12345678/DXB/LHR HWB/FWDDXB-HB001/DXB/LHR SHP/TECH SUPPLIES FZE SILICON OASIS/DUBAI/AE CNE/MIDLANDS TECH LTD BIRMINGHAM BUSINESS PARK/GB CVD/K/120.0/2/60/40/50/CM NME/LAPTOP COMPUTERS SRI/ELI ZZZZ
FFM — Flight Manifest Message
The FFM (Freight Flight Manifest) is generated by the departure station and transmitted to all transit and destination stations before or at the time of aircraft departure. It lists every piece of cargo on board — both ULD-loaded and loose cargo — and is the primary document used by handlers to prepare for arrival.
FFM messages are critical for advance cargo information (ACI) regulatory compliance in many countries, including the EU, US, and Canada, where pre-arrival data must be submitted to customs authorities.
FFM Structure Overview
| Segment | Description | Example |
|---|---|---|
| FFM | Message type and version | FFM/8 |
| FLT | Flight details — carrier, flight number, date, origin, destination | FLT/EK/521/15MAR25/DXB/LHR |
| ULD | ULD identifier — type, serial, airline code | ULD/PMC/12345/EK |
| AWB | Airway bill attached to the ULD or loose | AWB/176-12345678/K/500.0/5/T |
| SPH | Special handling codes for the piece/ULD | SPH/ELI |
| CNT | Shipment count — total AWBs and pieces on flight | CNT/12/45 |
.LHREKXH EKDXBXH 151030 FFM/8 FLT/EK/521/15MAR25/DXB/LHR ULD/PMC/12345EK/EK/LHR AWB/176-12345678/K/500.0/5/T SPH/ELI NME/CONSUMER ELECTRONICS ULD/AKE/98765EK/EK/LHR AWB/176-98765432/K/85.0/3/T NME/PHARMACEUTICALS SPH/PIL/COL CNT/2/8 ZZZZ
FSU — Freight Status Update
The FSU (Freight Status Update) is one of the most frequently exchanged messages in air cargo. It is generated automatically by airline systems at key milestones in the shipment journey and transmitted to freight forwarders, customs, and other stakeholders.
Each FSU carries a status code that identifies what happened to the shipment. Understanding FSU status codes is essential for track-and-trace systems and exception management.
Common FSU Status Codes
| Code | Event | Description |
|---|---|---|
| RCS | Received from Shipper | Cargo accepted at origin station from shipper or forwarder |
| MAN | Manifested | Shipment has been manifested on a specific flight |
| DEP | Departed | Flight has departed with the shipment on board |
| ARR | Arrived | Flight has arrived at destination or transit station |
| RCF | Received from Flight | Cargo offloaded and received at the station |
| NFD | Notified | Consignee has been notified of cargo arrival |
| AWD | Docs to Customs | Documents submitted to customs for clearance |
| CCD | Customs Cleared | Shipment cleared by customs authorities |
| DLV | Delivered | Cargo delivered to consignee or their agent |
| DIS | Discrepancy | A discrepancy has been found — damage, shortage, overage |
| FOH | Freight on Hand | Cargo held at station, not yet manifested on a flight |
| TRM | Transferred | Cargo transferred to another carrier or location |
.FWDDXBAA EKDXBXH 151045 FSU/14 AWB/176-12345678 DEP/15MAR25/1030/EK521/DXB/LHR CVD/K/500.0/5 ZZZZ
.FWDDXBAA EKLHRXH 151435 FSU/14 AWB/176-12345678 DIS/15MAR25/1420/LHR CVD/K/480.0/5 SHP/SHORTAGE/20KG MISSING ON ARRIVAL ZZZZ
FMA & FNA — Flight Movement Advice
The FMA (Flight Movement Advice) confirms that a flight has departed or arrived, providing actual times. Downstream systems use FMA to trigger arrival processing, resource planning, and status updates.
The FNA (Flight Not Operated Advice) is the counterpart message, sent when a scheduled flight will not operate. Receipt of an FNA triggers urgent rebooking processes for all affected cargo.
.LHREKXH EKDXBXH 151050 FMA/3 FLT/EK521/15MAR25 DEP/DXB/1035/LHR ETA/LHR/1405 ZZZZ
.LHREKXH EKDXBXH 150600 FNA/3 FLT/EK521/15MAR25 ORG/DXB/LHR OSI/FLIGHT CANCELLED DUE TO OPERATIONAL REASONS OSI/CARGO TO BE REBOOKED ON EK523/16MAR25 ZZZZ
FCR — Cargo Release Message
The FCR (Freight Cargo Release) message authorises the release of a specific shipment to a named consignee, customs broker, or ground handling agent. It is typically generated after customs clearance has been obtained and payment of charges confirmed.
FCR is critical in controlling who can collect cargo at destination — it acts as the electronic delivery order and replaces the need for a physical AWB original in many modern operations.
.EKLHRXH FWDDXBAA 151500 FCR/3 AWB/176-12345678 CNE/GLOBAL IMPORTS LTD UNIT 5 HEATHROW LOGISTICS PARK/LONDON/GB REL/15MAR25/1500/LHR AGT/87654321/HEATHROW CUSTOMS BROKERS OSI/CUSTOMS CLEARED REF GB123456789 ZZZZ
The Complete Shipment Message Flow
In practice, a typical international air cargo shipment generates the following sequence of IMP messages from booking to delivery:
Special Handling Codes in IMP Messages
IMP messages use IATA Special Handling Codes (SPH) to communicate commodity-specific requirements. These three-letter codes appear in SRI and SPH segments and dictate how cargo must be stored, transported, and handled. Below are the most common codes you will encounter:
| Code | Category | Meaning |
|---|---|---|
| PIL | Pharmaceutical | Pharmaceuticals requiring temperature control (+15°C to +25°C) |
| COL | Cold Chain | Perishable cargo requiring refrigeration (+2°C to +8°C) |
| FRO | Frozen | Deep frozen shipments (-18°C or below) |
| ELI | Lithium Batteries | Lithium ion/metal batteries — regulated DG |
| PER | Perishable | Perishable goods requiring priority handling |
| AVI | Live Animals | Live animals — IATA LAR regulations apply |
| VAL | Valuable Cargo | High value cargo requiring security vault storage |
| DGR | Dangerous Goods | IATA DGR regulated hazardous materials |
| HEA | Heavy Cargo | Individual pieces exceeding 150kg |
| HUM | Human Remains | Human remains — requires specific documentation |
| VUN | Vulnerable | Fragile cargo requiring careful handling |
| AOG | Aircraft on Ground | Priority AOG spare parts shipment |
IMP vs. Cargo-XML (CIMP)
IATA introduced Cargo-XML as the modern successor to IMP Type B messaging. While IMP uses plain ASCII text, Cargo-XML uses structured XML schemas and is designed for web services, REST APIs, and modern cargo community systems.
Both standards coexist today. Most large airlines, GHAs, and freight forwarders operate dual stacks — accepting and generating both IMP Type B and Cargo-XML. Many community systems (Cargo Community Systems like CHAMP, CargoSphere) translate between them automatically. New integrations increasingly use Cargo-XML, but Type B remains dominant in operational messaging, particularly for FSU status updates and FFM manifests.
| Feature | IMP Type B | Cargo-XML |
|---|---|---|
| Format | Plain ASCII text, line-based | XML, structured schema |
| Transport | SITA/ARINC Type B network | HTTP/S, REST, SOAP, AS2 |
| Validation | Manual parsing rules | XSD schema validation |
| Human readable | Yes, with training | Verbose but structured |
| Industry adoption | Universal (legacy) | Growing (modern systems) |
| Regulatory use | Widely accepted | Increasingly mandated |
Building Systems That Process IMP Messages
If you are building or integrating systems that handle IMP Type B messages, here are the key engineering considerations:
- Message parsing: Build a segment-based parser that reads line by line, identifies the segment code, and extracts fields by position and slash delimiter. Handle continuation lines carefully.
- Validation: Validate mandatory segments per message type, check AWB number format (3-digit prefix + 8-digit serial), validate date/time formats, and verify IATA airport and airline codes.
- Encoding: IMP messages are 7-bit ASCII. Handle encoding carefully when interfacing with modern UTF-8 systems — special characters in consignee names can cause parsing failures.
- Acknowledgement: Implement SITA network acknowledgements (ACK/NAK) for reliable delivery. Failed transmissions require retry logic with exponential backoff.
- Duplicate detection: Messages can be retransmitted. Use AWB number + message type + timestamp composite keys for deduplication.
- AWB state machine: Model the shipment lifecycle as a state machine driven by FSU status codes. Not all status transitions are valid — e.g., DLV cannot follow DIS without RCS.
SkyMantix has 20+ years of hands-on experience building and integrating air cargo systems that process IMP Type B messages at scale — from Oracle APEX-based cargo portals to cloud-hosted message brokers on AWS and OCI. If you are building a cargo system that needs to speak IMP, we can help.