April 11- Investors are raising questions about the viability of the SAR6 billion ($1.6 billion) private airport in Madinah, when the authorities have been unable to collect fees from the government carrier Saudi Arabian Airlines. 
The airline owes billions of riyals to the General Authority for Civil Aviation (GACA), which regulates the industry and owns the kingdom's airports and was on a road show in Dubai recently to test investor interests. According to source, firms like the HSBC, Australian bank Macquarie Capital, and local contractors Saudi Oger and Saudi Binladin Group attended the meetings in Dubai last week and were concerned about the Saudi Arabian Airlines' outstanding bills. The carrier, owes SAR11 billion to GACA.
Sources added that this huge unpaid bill as well as the money the kingdom spends on its airline along with large discounts for fuel has weakened the sector and hurt upstart private carriers.
Both Saudi Airlines and GACA have decided to privatize their assets in the coming years.