Real life YMEN Question

[EasternT3]

A quick question for any Orbx Staff at YMEN and or anyone else who knows, what's the largest aircraft allowed at YMEN? Can the airport take a 737 BBJ? I can't find any information

 

Thanks

Joe

[aussieh]

6 hours ago, EasternT3 said:

A quick question for any Orbx Staff at YMEN and or anyone else who knows, what's the largest aircraft allowed at YMEN? Can the airport take a 737 BBJ? I can't find any information

 

Thanks

Joe

Hi Joe,

I found an article online from 2018 mentioning the Federal Government here had increased the limit from 45,000kg to 50,000kg (Source), however that is really only part of the story. Essendon Fields website reports that any aircraft with Maximum Take-Off Weight (MTOW) of 50,000kg (110,230lbs) or tyre pressure greater than 1400kpa (203psi) requires a pavement concession (Source). From limited searching, it appears the BBJ1 MTOW is 171,000 lb (77,564 kg) and Goodyear reports their tyre needs to be inflated to 214psi. I would imagine the BBJ2 figures would be higher meaning the BBJ requires a pavement concession to land at YMEN. 

 

YMEN website states:

Quote

If a pavement concession is required, a Pavement Concession Application form must be completed and provided to Essendon Fields Airport a minimum of 2 business days prior to the planned aircraft arrival date.  The application will be assessed on the basis of pavement strengths and surface characteristics only, and approval may be withdrawn at any time should pavement damage occur.

 

Application fee $250 (plus landing fees)

 

Short Answer: It's up to the Aerodrome Operator to decide whether they accept a BBJ or not. To my knowledge, BBJ's and larger tend to land at Tullamarine instead. 707's have landed there and apparently the maximum to date for weight is 148,325kg - Lyndon B. Johnson's Air Force One C-137 Stratoliner in 1966 and again in 1967. Do BBJ's land there regularly? Not to my knowledge. Could a BBJ feasibly land there? Likely possible with restrictions and a pavement concession.

 

The Background

Spoiler

I'm not sure of your aviation knowledge level so I'll write it as simply as I can (please accept my apologies if anything comes of as condescending - definitely not intended):

 

The size of the aircraft able to land is determined by both Maximum Take-Off Weight (MTOW) and tyre pressure. This is complicated further by the type of pavement (asphalt, concrete, etc.) and whether it's rigid or flexible. The Aeronautical Information Publication (AIP) and their counterparts (Jeppesen, etc.) publish these numbers in the aerodrome directory. This is referred to as the "Pavement Concession Number" or "PCN." The PCN is calculated for different runways, different taxiways and different aprons. The AIP figures apply to the respective runway, and then you may have MTOW taxiway restrictions listed on the respective aerodrome charts. Obviously, wingspan also comes into play however this is a different conversation.

 

An "Aircraft Classification Number" (or ACN) is also calculated and as long as ACN (at a given weight) ≤ the PCN, the aircraft may land without restriction. However, as alluded to earlier there is the capacity to obtain a waiver or dispensation to operate an aircraft that is higher than the PCN. This may or may not come with further flight specific restrictions. A good example of this was when Qantas moved the retiring 747-438 VH-OJA from Sydney to the Historical Aircraft Restoration Society (HARS) in Wollongong (YSHL). Other than the other various dispensations required, it was reported that Engineers deflated the tyres to a much lower PSI as is normal thus reducing the ACN. I understand a pavement dispensation was still required, but that would have reduced the amount of damage that may have occurred. The lower PSI was obviously appropriate to the substantially lower operating weight, with normal inflation being calculated for absolute MTOW (plus safety margin).

 

Wikipedia has a good overview for the calculation of ACN and PCN per ICAO specifications. 

 

Quote

According to the Wikipedia entry:

If the ACN exceeds the PCN, some restrictions (for example on weight of frequency of operation) may apply depending on the national or local regulations for overload operations.

 

With the exception of massive overloading, pavements in their structural behaviour are not subject to particular limiting load above which they suddenly or catastrophically fail.

 

As a result, minor or medium overload operations may be allowed by the airport authority depending on the corresponding loss in pavement life expectancy.

 

In 2020, with changes in aircraft and pavement design, the ACN-PCN method was deemed no longer appropriate and ICAO moved to a new Aircraft Classification Rating - Pavement Classification Rating (ACR-PCR) method.

 

Regardless, when determining whether to issue a dispensation the aerodrome operator would need to determine whether they are happy to accept the corresponding loss in pavement life expectancy which would also need to take into account previous dispensations and how often the dispensation landings occur. A dedicated runway inspection would also normally occur after a dispensation landing and prior to any departures to ensure no pavement failure has occurred.

Cheers,

[EasternT3]

Hi Hayden,

 

Thanks for the response, it's really helpful. I'll guess I will pretend to get a pavement concession until Tullamarine is released later this year  

 

Joe

[aussieh]

1 minute ago, EasternT3 said:

Hi Hayden,

 

Thanks for the response, it's really helpful. I'll guess I will pretend to get a pavement concession until Tullamarine is released later this year  

 

Joe

No problems Joe - $250 each time, thanks 

[Richard Lincoln]

I ocasionally work out of YMEN, the biggest I have scene is Lindsy's Global Jet, not sure if the 2 DC3's that run out of there are bigger.

[wolfko]

Perhaps a way to find out, if there has hever been a BBJ at YMEN, was checking the pics archive at airliners.net.

BTW I once heard, that decades ago a large plane (don't know the type) landed at Essendon by error, because the crew had mistaken YMEN for YMML. The problem then was to get the plane out of Essendon again, because the runways were too short. I don't know, how they solved the problem.

Can anybody confirm this story?