A04H0001 - Interim Aviation Safety Recommendations
Standard Passenger Weights - Use and Validity of Standard Values

Validity of Standard Weight Values

On 27 January 2003, the Federal Aviation Administration (FAA) issued Notice N8400.40 in reaction to a recent commuter air crash that had raised concerns related to aircraft loading and the use of average weights in weight and balance control programs. The Notice required operators of aircraft with 10 to 19 seats to conduct a survey to validate average passenger weights. The results of the survey indicated that the current standard weight values contained in FAA Advisory Circular 120-27C (dated 11 July 1995) underestimate the average weight of passengers by 20.63 pounds and underestimate the average weight of carry-on baggage by 5.72 pounds.

In light of the similarity between Canadian and American demographics, it is reasonable to conclude that the average weights published in A.I.P. Canada, which include both the weight of passengers and carry-on baggage, no longer reflect the current realities of Canadian society. It is therefore likely that many flights conducted in Canada are operating at a heavier weight than calculated.

The average weight of the passengers on Georgian Express Flight 126 using standard weights was 183.3 pounds (9 men at 188 pounds, 1 woman at 141 pounds). Using actual weights, the average passenger weight was 240 pounds. This represents an increase of 56.7 pounds per passenger from the published standard weights. This is a biased sample, but nonetheless indicates the increased weight of the Canadian population.

The Canadian Aviation Safety Board (the Transportation Safety Board of Canada's predecessor) issued three safety recommendations during the investigation into the crash of a DC-8 aircraft in Gander, Newfoundland (CASB 86-01, 86-02 and 86-03, dated 13 February 1986). These recommendations to Transport Canada (TC) and the National Transportation Safety Board (NTSB) in the United States were directed towards the adequacy of provisions for the use of actual weights versus standard weights. The responses from TC and the NTSB were fully accepted by the Board.

Use of Standard Weights in Small Aircraft

In any statistical application, the larger the sample size, the more closely the sample mean will match the population mean. For large airliners, deviations between the calculated standard passenger weight and the actual weight are minimized by the larger sample size of passengers. Additionally, some airlines apply a larger ratio of men to women to further minimize any weight discrepancies.

A comparison of various aircraft types indicates that the ratio of passenger weight to overall aircraft weight is inversely proportional to the size of the aircraft. For example, in a Boeing 747, the passenger weight represents approximately 9 per cent of the aircraft's weight (450 passengers at 188 pounds, aircraft of 875 000 pounds) whereas the passenger weight in a Caravan can represent approximately 22 per cent (10 passengers at 188 pounds, aircraft of 8550 pounds). For aircraft under 12 500 pounds, there can be significant deviations from the published standard passenger weights due to the small sample size (nine passengers or fewer). This deviation error is further amplified in small aircraft due to the higher percentage of total aircraft weight that the passengers represent. If a small aircraft is being loaded to maximum gross weight, this discrepancy in passenger weight could result in an overweight condition that adversely affects the safety of flight. For example, stall speeds increase with increased aircraft weight; if the pilot is unaware of this change to aircraft performance, the reference speeds used for critical phases of flight will be incorrect.

The NTSB has published numerous recommendations relating to the calculation of aircraft weight. Several of these recommendations dealt specifically with aircraft under 12 500 pounds and the issue of standard versus actual weight. In response to these recommendations, the FAA released an Advisory Circular (120-27C, dated 11 July 1995) outlining the new policy on aircraft weight and balance control. This document states that actual weights for passengers are to be used for aircraft carrying nine passengers or fewer.

There have been numerous accidents in Canada related to overweight aircraft. At least five of these accidents involved small aircraft where discrepancies between the standard and actual weight of passengers contributed to the overweight condition and the accident. Four of these accidents were fatal, involving 24 fatalities. There are 3564 commercial aircraft in the small aircraft category (less than 12 500 pounds) operating in Canada. These aircraft conduct thousands of flights on a daily basis. Companies will naturally try to maximize the load to optimize the service and remain competitive with other companies. This means that, on any given day, many flights operate at close to maximum gross weight on paper when, in fact, some of these flights are operating above maximum gross weight. The use of standard weights in these aircraft exposes the industry to a high degree of risk.

TC's Generic Company Operations Manual - CAR 704, section 3.9.6, and A.I.P. Canada RAC 3.5 state that actual weight should be used to calculate passenger weight unless that information is unavailable. Air operators have three options to calculate passenger weight: use actual weight, use standard weights as published in A.I.P. Canada RAC 3.5, or use standard weights obtained through an operator survey. The most common practice is to use standard weights, as indicated in the Pelee Island operation where standard weights were used for 155 of the 165 flights.

The defences against the risks associated with using standard weights are not adequate for aircraft carrying nine passengers or fewer. The use of actual passenger weights in small aircraft would provide a greater margin of safety. Additionally, the surveyed passenger weights in the United States and the investigation results indicate that the published standard weights no longer reflect Canadian society. It is therefore likely that many flights conducted in Canada are operating at a heavier weight than calculated.

Therefore, the Board recommends that:

The Department of Transport require that actual passenger weights be used for aircraft involved in commercial or air taxi operations with a capacity of nine passengers or fewer. (A04-01)

Transport Canada's Response:

Current regulations make it clear that air operators are to ensure that their aircraft are flown within the limits of the weight and balance envelope and that the standards provide options that may be used but do not override the regulatory requirement to remain within the weight limits of the aircraft. Transport Canada (TC) continues to review the standards with a view to improving the direction provided. One option that is under consideration is the use of actual weights for all operations conducted under subpart 3 (Air Taxi Operations) of Part VII (Commercial Air Services) in the Canadian Air Regulations (CARs). Once our review, including a risk assessment, is complete, Notice of Proposed Amendments (NPAs), (if required) will be developed and submitted to the Canadian Aviation Regulation Advisory Council (CARAC) for consultation.

The Department of Transport re-evaluate the standard weights for passengers and carry-on baggage and adjust them for all aircraft to reflect the current realities. (A04-02)

Transport Canada's Response:

TC re-evaluated the standard weights for passengers and carry-on baggage and adjusted them for all aircraft to reflect the current realities.

Commercial & Business Aviation Advisory Circular (CBAAC 0235) and Policy Letter were issued in October and the Aeronautical Information Publication (A.I.P.) published weights will be amended January 20, 2005 (see chart below). Operators whose approved weight and balance control program is based on the A.I.P. weights will need to amend their programs to reflect these new weights.

*Add where infants exceed 10% of Adults.

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