The fact that aviation incidents and accidents are recorded in detail enables us to analyse frequencies and types, as well as categorise causal factors. However, there may be slight differences in the structure of databases and searches into the records have to take into account the terminology used during the reporting of those occurrences and categorisation used for keeping records. The following are examples of some established sources of safety information that could be accessed for analysis purposes.
3.4.1.1 FAA Aviation Safety Information Analysis and Sharing (ASIAS)
The ASIAS (formerly NASDAC) databases have been updated and still available for online search as before (FAA, 2006). The relevant databases are the Aviation Safety Reporting Scheme (ASRS), FAA Aircraft Incident data System (FAIDS), National Transportation Safety Bureau (NTSB) and Near Mid- Air Collision System (NMACS).
These databases could be searched by various criteria such as aircraft types, flight type, state, airport and events between two dates. A narrative contents search could be carried out using keywords. A search result will provide query count, total events count and each individual report. Keywords such as ATC, tower, tracon, language, phraseology and miscommunication were used for specific searches. Boolean logic allows for combined keywords search to narrow down the search area scope.
Table 3-5 lists the various search results carried out in September 2007 using keywords associated with this research. Based on events recorded, ASRS has the largest database and the NMACS the smallest. Reports containing the search keyword were listed and details could be extracted online. The table only shows the number of relevant events. However, as these events keywords were not totally independent of each other, the numbers should not simply be added up. Multiple keywords search could assist in narrowing down search criteria and type of events.
Table 3-5: FAA’s Databases Search Results (September 2007)
ASRS FAIDS NTSB NMACS
Total Events 176570 88373 63167 6351 ATC 32366 1576 1625 310 Tracon 3127 37 332 78 Enroute 345 1819 885 83 Tower 223 1907 3369 237 Language 912 9 47 1 Phraseology 811 5 28 3 Miscommunication 25 7 6 0 English 637 9 57 0
ATC & language 227 2 8 0 ATC and phraseology 254 2 15 1 ATC & miscommunication 9 3 1 0 ATC & English 174 2 7 0 Tracon & language 6 0 2 0 Tracon and phraseology 27 (0.015%) 0 6 1 Tracon & miscommunication 1 0 0 0 Tracon & English 5 0 4 0 Enroute & language 2 0 1 0 Enroute and phraseology 1 0 3 0 Enroute & miscommunication 0 0 0 0 Enroute & English 0 0 2 0 Tower & language 1 1 16 (0.025%) 0 Tower and phraseology 0 1 18 (0.028%) 1 Tower & miscommunication 3 1 2 0 Tower & English 1 0 18 (0.028%) 0
Not all events were ATC related or associated with any ATC operations environment. For example, NMACS has only 78 out of 6351 records pertaining to ‘tracon’ and only 1 was ‘tracon and phraseology’ related. ‘English’ and ‘miscommunication’ were not associated with any event in NMACS but found in other databases. The NTSB database showed more records associated with Tower (with language or phraseology or English). ‘Tracon and phraseology’ showed more records in ASRS. These databases gave an idea of how much the language, phraseology and communication problems affected the ATC operations.
3.4.1.2 UK MORS
A search on MORs for ‘language’ resulted in 230 reports and ‘phraseology’ resulted in 143 reports. Other MORS reports listed in the ‘language’ search are in Appendix C and those categorised by ‘phraseology’, in Appendix D. Each report contains aircraft type, flight phase, event category, location, date, a pre-
The following Table 3-6 is an example of a MORS report that was listed under ‘language’ keyword search. The incident is of an altitude deviation event that took place in Spain involving an Airbus-320.
Table 3-6: Example of UK MORS ‘language’ Search Results
A/C Type : A320 Occurrence Number: 00XYZ
Flight Phase : Climb Occurrence Date : ddmmyy
Classification : Occurrences Location : Spain
Events : Altitude Deviation (ATC) Foreign ATC Occurrence
Location Info :
Pretitle :
After take off A320 changed frequency at 200ft, but was unable to contact new frequency until FL49, when clearance was amended to maintain 5000ft. A320 reached 5350ft before descending back to 5000ft.
Precis :
After take off from R/W36L, at 200ft, A320 was given frequency change by Tower, which was acknowledged and actioned. New frequency did not respond to initial call, also all other R/T transmissions were in local language. ATC eventually contacted A320 when it was at FL49 and instructed it to maintain 5000ft, due to the slow climb of the preceding a/c. A320 climbing to FL130 on the SID, disconnected autopilot, but reached 5350ft before descending back to 5000ft.
The pilot reported that a clearance to maintain level was not timely and resulted in a level bust before the aircraft could descend to its assigned level. Usage of local language in radiotelephony with other aircraft on the frequency was claimed by the pilot as contributory to the occurrence.
In the Table 3-7 example, listed under ‘phraseology’, there was confusion over prominent words ‘line up’ and ‘ready immediately’ which had resulted in runway incursion when the pilot fail to notice the requirement ‘after landing traffic’.
Table 3-7: Example of UK MORS ‘phraseology’ Search Result
A/C Type : B737 Occurrence Number : 0WXYZ
Flight Phase : Taxy Occurrence Date : ddmmyy
Classification : Occurrences Location : UK
Events : ATC Occurrence
Runway Incursion
Location Info :
Pretitle :
B737 was given a conditional line up clearance from R3 holding point after a landing B737, but then observed to have crossed red stop bar ahead of a landing B737. Inbound B737 instructed to go around.
Precis :
Inbound B737 at approximately 2nms on final approach to R/W23 was cleared to land. Another B737 was given a conditional line up clearance from R3 holding point to 'line up
after landing traffic and be ready immediately'. B737 subsequently observed to have
crossed red stop bar ahead of landing B737 and instructed to hold position. Both pilots believed initial instruction was 'line up and be ready immediately'. Inbound B737 instructed to go around.
Normally, a restriction is issued ahead of the instruction to emphasise to the pilot that there is a condition to be met. Structuring the message differently may give pilots the wrong impression as had happened in this occurrence.
3.4.1.3 Aviation Safety Network
This website’s database reports are categorised under various headings such as regions and countries, year, contributory factor and outcome.
Table 3-8: Occurrences Attributed to Language/ Communications Problems Year Location Commentary on language / phraseology 1997 Indonesia ATC confusion over direction of aircraft turn
1996 Norway Pilot’s limited knowledge of the operating language. Request for alternate runway not understood by ATC Information
1992 Thailand language difficulties, ineffective discussion of unresolved problems, radio communication difficulties between the crew and the air traffic controllers.
1991 California failure of ATC to maintain situation awareness of traffic situation, culminating in inappropriate clearances
1989 Malaysia "...descend two four zero zero..." was interpreted by the crew as "...to 400..."Non-standard phraseology by ATC, crew misinterpret instructions
1985 New Jersey inadequate coordination among ATC, a misleading traffic advisory. 1981 France imprecise language between pilot and ATC
aircraft flying a holding pattern to lose altitude, but the controller believed aircraft was on direct descent to begin final approach. 1981 California Crew failure to immediately initiate a go-around when instructed to do
so by the ATC
1979 India ATC use of incorrect and/or non-standard phraseology
1979 Brazil '…turn right heading 140, just now, over' Incomplete ATC instructions, 1979 Italy inadequate ATC assistance (controller distracted)
1977 Lebanon Language difficulties forced Beirut Area Control to repeat approach instructions.
1977 Spain misunderstanding between the tower and the crew, aircraft departed without take-off clearance, mutual use of usual terminology which, however, gave rise to misinterpretation.
1977 California crew misinterpreted the IFR clearance and ATC instructions
1975 Washington ATC: "...maintain five thousand", flight responded "Five thousand. MAC 40641 is out of ten". Misidentification.
1973 France Radio difficulty due distance. crew twice tried to request permission to carry out a 360-degree turn, initiated the turn without clearance. 1969 Puerto Rico Wrong position information and erroneous instructions, controller was
performing beyond the safe limits of his capability
1966 France "you have 5 miles to the Mont Blanc" the positional correction by ATC was mis-understood by the pilot
1960 Brazil lack of appreciation of the communications difficulties,
pilot misunderstand instructions transmitted by Approach Control 1947 Senegal radiotelephony communications difficulties between the control tower
and the aircraft, insufficient knowledge of the English language by the controllers in the tower
A causal/ contributory factor search listed 21 accidents (Table 3-8) associated with language/ communications problems. Among the language related keywords used in the narrative of the accidents were confusion, limited knowledge, difficulties (speaking/ understanding), non-standard phraselogy, misleading, misinterpretation and imprecise. Based on location, these accidents were not limited to non-native English speaker countries, which suggest that language problems are not always ESL associated.