type
  TFailureEntry = TPair<System.Word, TMyFailureRecord>;

procedure TMyClass.GetFailureAbbreviations;
var
  FailureArray: TArray<TFailureEntry>;
  Comparison: TComparison<TFailureEntry>;
begin
  // derrive the array contents from a dictionary
  FailureArray := FFailureDictionary.ToArray;

  Comparison :=
    function(const Left, Right: TFailureEntry): Integer
    begin
      Result := Left.Key-Right.Key;
    end;

  FailureArray.Sort(TComparer<TFailureEntry>.Construct(Comparison));
end;