Loss of Control on Go-around-Fredericton Airport-NB-16 December 1997
Safety Action Taken
(as presented in the TSB report)
Use of Aircraft Anti-Ice
It was discovered during the investigation that operating procedures, combined with the limitations of the ice-detection system, would not ensure that the aircraft wings and engines would be free of ice during flight.
On 11 March 1998, to address the issue of the "ICE" caution being inhibited below the radio altitude of 400 feet agl, Air Canada issued Aircraft Technical Bulletin No. 158 amending the procedures in its AOM (Volume 2/02.00- .02/ .30- .43) as follows:
During flight, the engine cowl and wing anti-ice system must be ON when:
icing conditions are indicated by the ice detection system, or
there is visual detection of ice formation on the airplane surfaces (windshield wipers, window frames, etc.), or
operating below 400 agl and icing conditions exist as defined by the AOM, Vol. 2, 02.17.01, or
an ice detector has failed and icing conditions exist as defined by the AOM, Vol. 2, 02.17.01.
Bombardier Regional Aircraft Division, with Transport Canada approval, issued All Operator Message No. 234, dated 20 March 1998, referring to Temporary Revision RJ/61 which was sent to all CL-65 operators. The temporary revision consolidated and clarified icing definitions and procedures for operation in icing conditions, as defined in the Airplane Flight Manual, CSP A-012, to ensure that the ice protection systems are activated whenever the aircraft is operating in conditions that could lead to ice accumulating on the wing and engine cowl leading edges.
The procedures outlined in Air Canada's Aircraft Technical Bulletin and in Bombardier's All Operator Message will reduce the possibility of ice accumulation on the CL-65 aircraft.
Nevertheless, there is still a risk that while an aircraft is operating below 400 feet agl, ice could accumulate to an extent that aircraft performance would be materially affected without the pilots being aware that they had entered icing conditions or that ice had accumulated. If the amber ICE light were not inhibited below 400 feet, however, an extra safe-guard would be in place to alert pilots to the presence of ice.
The Federal Aviation Administration (USA) considers illumination of the amber ICE light to be a warning light, not a caution light. Consequently illumination of the amber light is not inhibited on CL-65 aircraft registered in the USA.
It is acknowledged that illumination of the amber ICE light at low altitude could introduce some risk by distracting the crew; however, this risk must be compared to the risk associated with the increased potential for ice accumulating during a critical stage of flight if illumination of the amber ICE light is inhibited. To reduce the risk of aircraft stall during a critical stage of flight, the TSB issued an Aviation Safety Advisory on 9 April 1999, suggesting that Transport Canada consider taking action to remove the inhibition of the amber ICE light below 400 feet agl on existing and future CL-65 aircraft.
Requirement for an Emergency Locator Transmitter
In reviewing the requirement for Emergency Locator Transmitters (ELTs), the TSB noted that under CAR 605.38(3), multi-engine turbo-jet aeroplanes of more than 5700 kg (12 500 pounds) maximum certified take-off weight, such as the Canadair CL-65, when operating in IFR flight within controlled airspace, over land, and south of latitude 6630' N, are not required to be equipped with an ELT. This "exemption" did not apply to non-turbo-jet aeroplanes (like the Dash-8 and ATR-42) which are similar to the CL-65 in terms of passenger capacity, operational environment, and engine reliability.
TSB information indicates that there is no significant difference in accident rates--between aeroplanes of similar size--strictly as a function of their being turbo-prop versus turbo-jet. Risk mitigation with respect to post-crash survivability that is gained by being equipped with an ELT, such as ELT-assisted search and rescue efforts, applies to all aircraft, regardless of the type of propulsion system.
On 24 February 1998 the TSB issued Aviation Safety Advisory 980004 , suggesting that Transport Canada consider reviewing CAR 605.38(3) with a view to eliminating the ELT carriage exemption for turbo-jet aircraft.
On 3 April 1998 Transport Canada reported that, given the concerns raised in TSB Advisory 980004 and the time interval since the original regulation was promulgated, the General Operating and Flight Rules Technical Committee of the Canadian Aviation Regulation Advisory Council had been tasked to review the adequacy of existing regulation regarding ELT requirements.
Transport Canada has since advised that the Civil Aviation Regulatory Committee, at its 11 December 1998 meeting, decided to initiate amendments to CAR 605.38 to require multi-engine turbo-jet aircraft of more than 5700 kg maximum certified take-off weight operating in IFR flight within controlled airspace to carry an ELT.
Aircraft Low-Energy Issues
When the go-around was initiated, the aircraft was configured for landing, it was at a low height above the runway, the airspeed was decreasing, and the engines were at idle. The aircraft was not able to complete the go-around manoeuvre without ground contact because it was in a low-energy state.
On 13 May 1998 Transport Canada issued a Commercial and Business Aviation Advisory Circular to notify pilots and air operators of the potential hazards associated with a balked landing or go-around. The circular states that an aircraft is not certified to successfully complete a go-around without ground contact once it has entered the low-energy landing regime. For the purposes of the circular, the low-energy landing regime is defined as follows:
aircraft flaps and landing gear are in the landing configuration;
aircraft is in descent;
thrust has stabilized in the idle range;
airspeed is decreasing; and
aircraft height is 50 feet* or less above the runway elevation.
* Note: 50 feet is a representative value. A given aircraft may enter the low-energy landing regime above or below 50 feet in accordance with approved landing procedures for that type.
The circular further stated that the decision to place an aircraft in the low-energy regime is a decision to land; if there is any doubt regarding the probability of a safe landing, a go-around must be initiated prior to entry into this regime. An attempt to commence a go-around or balked landing while in the low-energy landing regime is a high-risk, undemonstrated manoeuvre. In the extreme case where such action is required, pilots should be aware that ground contact is likely and any attempt to commence a climb before the engines have achieved go-around thrust may result in a stall.
The circular advised that air operators should immediately ensure that their pilots and training personnel are aware of the hazards associated with low-energy go-arounds or balked landings and verify that their training programs address the hazards inherent in, and procedures for dealing with, low-energy operations.
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