Aviation Safety Letter 4-2003
To the Letter — Use of "Clear" and "Cleared" in ATC Phraseology
After the largest air disaster ever in Tenerife in 1977, the International Civil Aviation Organization (ICAO) issued advisories on phraseology changes to avoid the use of words that could be misinterpreted. Confusion around the words "CLEAR" and "CLEARED" was fundamental to this tragic accident, so the most important change was that the word CLEARED was to be used only where a clearance is given for takeoff or landing. A couple of years after the event, the Dutch aviation authorities mandated those changes to the ATC phraseology, but I was unable to determine if the new phraseology implemented in Canada. Human and technical communication limitations make it easy to confuse "clear" with "cleared". Add to this fast aviation jargon and pilots whose mother tongue is not English, and the potential for misunderstandings is "clear".
Arthur van Maurik
Piloot & Vliegtuig magazine
The ATC Manual of Operations (MANOPS) has a section pertaining to the use of the word "clear(ed)". It states, "Do not use words and terms "go ahead", "clear" or "cleared" in radiotelephony communications for ground vehicle operations." The purpose of a clearance is as follows: "An ATC clearance or instruction constitutes authority for an aircraft to proceed only in so far as known air traffic is concerned and is based solely on the need to safely expedite and separate air traffic. Pilots are required to comply with ATC clearances accepted by them and with ATC instructions directed to and acknowledged by them, subject to the pilot maintaining final responsibility for the aircraft's safety. Canadian controllers are directed to differentiate clearly between a clearance and an instruction by using the appropriate prefix, i.e: ATC clears, cleared or ATC suggests. NAV CANADA confirmed that it has adopted all the ICAO PANS ATM Doc 4444 articles that indicate the use of the words "clear" and "cleared" when issuing a clearance. NAV CANADA is therefore in compliance with ICAO-mandated phraseology in this respect. — Ed.
In Issue 2/2003 of the Aviation Safety Letter, your report of a collision between a helicopter and a Cessna 170 near Sandford Field, Ontario, illustrates a common problem for those of us flying out of private airstrips. Here in Fergus, Ontario, we frequently encounter aircraft flying over the airport or through the pattern at low altitude without calling or monitoring the recommended frequency 123.2. I once had a close encounter while descending through 600 ft AGL on short final. The other aircraft was just passing by, apparently totally oblivious to my presence or to the close proximity of the airport. As he did so, I heard him call Waterloo tower (Waterloo is 18 mi.away).
The Ontario Flying Farmers Airstrip Charts book lists over 300 private airstrips in Southern Ontario. Most are not marked on the charts, and it is impossible for pilots to know the locations of all private airstrips along their route. I suggest that everyone flying at less than 1 500 ft AGL outside of controlled airspace should continuously monitor 123.2.
In a perfect world, with all aircraft being equipped with two radios, pilots could monitor both 123.2 and 126.7 (the recommended frequency for "EN ROUTE VFR" in A.I.P. RAC 5.1), but we all know this is not the case. While 123.2 is recommended as a common advisory frequency for use at aerodromes that have neither a mandatory frequency (MF) nor an aerodrome traffic frequency (ATF) area (A.I.P. RAC 4.5.5), the pilot must be aware of the location of the private airstrip to begin with; local knowledge notwithstanding, infrequent flyers and transient pilots will likely be unaware of those private, uncharted airstrips. The best solution remains through education of proper procedures for VFR flight in uncontrolled airspace, emphasis on monitoring the appropriate frequencies, and making your presence known. A vigilant combination of AIRMANSHIP, LOOKOUT, and the "SEE-AND-AVOID" VFR principle will go a long way to prevent mid-air collisions in uncontrolled airspace. — Ed.
He's Just a Trainer, and We're an Airliner...
I run a flight school at a busy uncontrolled aerodrome, which has a mix of recreational flying, flight training and commuter traffic. One of our Class I instructors, who is also a Designated Flight Test Examiner, was flying circuits one day with a student. There were three light aircraft in the left-hand pattern for Runway 16. Typically, a commuter aircraft barged its way straight into the left base without organizing some realistic spacing ahead of two Cessnas that were established on the downwind leg. Inevitably there was a conflict between the first Cessna and the commuter aircraft at the base-to-final point. Our instructor and her student were in the second Cessna and extended their downwind slightly to stay back from the number one Cessna/commuter entaglement.
The commuter pilot announced on the radio (in an agitated manner) that he was now doing 'a two-seventy' to the right from base-to-final for spacing. Obviously this turn was very wide due to the commuter's speed — and it brought them into a conflict with the number two Cessna, which was now on left base. Although both Cessnas were making approptirate position calls, the commuter captain, distracted by having to avoid the first Cessna, forgot about the second one because his two-seventy to the right turned his back on the circuit traffic. Fortunately, our instructor in Cessna two had him visual all the way around this turn and was able to anticipate the conflict and avoid a collision.
But here's the kicker — in his shock at meeting the second Cessna the commuter captain said on the radio (quote) "what's that Cessna doing there? He should get out of our way — he's just a training and we're an airliner!" This comment drew a justifiable rebuff from the FSS specialist who pointed out that the "trainer" was perfectly in order — as it had been for the past hour. This event was damning evidence of the ineptitude and arrogance that we have to tolerate daily at our airport.
Name witheld on request
...to be continued. — Ed.
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