Reverse thrust policy for Fokker F100 landings
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Reverse thrust policy for Fokker F100 landings
Was told that Australian operators of the Fokker F100 have a policy to use only idle reverse on all landings - including wet runways. More than idle reverse discouraged although pilot discretion. Request the facts.
If you want the facts then:
(a) buy a ticket on a flight in a Fokker 100, with a landing at an aerodrome that is not 10,000+ feet in length, and experience the use of reverse thrust for yourself
(b) ring the company and ask them
(a) buy a ticket on a flight in a Fokker 100, with a landing at an aerodrome that is not 10,000+ feet in length, and experience the use of reverse thrust for yourself
(b) ring the company and ask them
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It is common at Port Moresby to see the Fokker 100 and 70's taxi with one reverser deployed at idle thrust to control taxi speed, especially with a tail wind.
Qantas Dash 8-400 crews quite often shutdown the left hand engine at Port Moresby mid way on the taxi to tarmac, to avoid riding the brakes
Qantas Dash 8-400 crews quite often shutdown the left hand engine at Port Moresby mid way on the taxi to tarmac, to avoid riding the brakes
Last edited by Mumbai Merlin; 9th Nov 2019 at 02:54. Reason: spelling
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Wow...this really is a first world problem to discuss on an Internet forum
Use of idle reverse for all landings might be relevant if noise abatement sensors are installed at some airports such as in Europe and noisy reverse thrust could mean withdrawal of slots at certain airports.
What people tend to forget is that if idle reverse is used after touchdown, especially if the surface is wet or even damp, and braking efficiency reduced, then if the decision is made suddenly to change to full reverse when the pilot belatedly realises that he should have used full reverse earlier, by then speed may have dropped off to the extent that full reverse is now ineffective.
There is evidence of many overseas accidents that have been caused by this policy. The landing end of some runways are often contaminated with rubber which when combined with water on the runway significantly reduces braking efficiency and can cause the tyres to skid.
Reverse thrust thrust is most efficient at high airspeeds and drops off significantly below 60-80 knots. A policy that discourages pilots from using full reverse after touchdown has the potential to lead to crew complacency not to mention hotter brakes.
The FCTM of one well known twin engine transport states in part: "For minimum brake heating select maximum reverse thrust as soon as possible after main gear touch down. The intention is to use reverse thrust as the major force that stops the airplane. The use of maximum reverse thrust further minimizes brake heating".
It’s been a while since, but I remember that with those Tays you had to transit from idle to full reverse in one streak. If you lingered too long in a certain EPR(?) range, you’d get a ‘Fan Blade Inspection’ ECAM (?) which required the engine to be boroscoped. Had to do with resonance\ vibrations. Like I said, it’s been 15 years...
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Apart from all the above, Fokker issued a directive as far back as 2005 that the use of more than idle reverse could cause damage to the engines and an inspection was mandated.if used.
Idle reverse is normally quite effective and can be used to reduce taxy speeds as mentioned..
The so called damage was noticed when some operators used reverse to "push back" so to speak i seem to recall.
For an RTO, fill your boots as engines are cheap vs the air frame.
Other types i had the privilage of flying variable from idle to full was SOP depending of all the things you can think of, and some you wont
Idle reverse is normally quite effective and can be used to reduce taxy speeds as mentioned..
The so called damage was noticed when some operators used reverse to "push back" so to speak i seem to recall.
For an RTO, fill your boots as engines are cheap vs the air frame.
Other types i had the privilage of flying variable from idle to full was SOP depending of all the things you can think of, and some you wont
It is common at Port Moresby to see the Fokker 100 and 70's taxi with one reverser deployed at idle thrust to control taxi speed, especially with a tail wind.
Qantas Dash 8-400 crews quite often shutdown the left hand engine at Port Moresby mid way on the taxi to tarmac, to avoid riding the brakes
Qantas Dash 8-400 crews quite often shutdown the left hand engine at Port Moresby mid way on the taxi to tarmac, to avoid riding the brakes
Greybeard,
Interesting your mention of a 2005 directive …. re use of more than 'idle reverse'
The PX guy's give the reversers a good work out at Madang when the runway is wet.
Recent volcanic activity which closed Hoskins to all traffic due volcanic ash, of course PX did not comply, there is plenty of video footage of Fokkers landing in the ash with hefty amounts of reverse. I think the Tay is very mature and almost indestructible?
Interesting your mention of a 2005 directive …. re use of more than 'idle reverse'
The PX guy's give the reversers a good work out at Madang when the runway is wet.
Recent volcanic activity which closed Hoskins to all traffic due volcanic ash, of course PX did not comply, there is plenty of video footage of Fokkers landing in the ash with hefty amounts of reverse. I think the Tay is very mature and almost indestructible?
Full reverse is more of a emergency procedure.
When pulled time & temp temp limits are important perhaps not as critical as the end of the runway but still to be considered.
Think it also triggers a message to management / engineering if pulled.
Personal opinion is that a lot has gone wrong with the approach & landing if full reverse has been pulled.
When pulled time & temp temp limits are important perhaps not as critical as the end of the runway but still to be considered.
Think it also triggers a message to management / engineering if pulled.
Personal opinion is that a lot has gone wrong with the approach & landing if full reverse has been pulled.
Idle reverse thrust has some advantages, especially with aft mounted engines/T tail combo in that it lessens the potential for rudder blanking. Think DAL 1086
other advantages:
slight fuel savings, GE outlines the savings in their materials, significant on a 4 holer, less so on smaller jets.
potential reduction in FOD events (determined by type)
noise abatement at some sensitive airports
other advantages:
slight fuel savings, GE outlines the savings in their materials, significant on a 4 holer, less so on smaller jets.
potential reduction in FOD events (determined by type)
noise abatement at some sensitive airports
http://www.boeing.com/commercial/aer..._17/brakes.pdf
The Fokker F100 FCOM recommends idle reverse for all landings except in an emergency. If full reverse used, maintenance action is required
The Fokker F100 FCOM recommends idle reverse for all landings except in an emergency. If full reverse used, maintenance action is required
Ditch the lapun jet and use Dash 8s, props are way better, Twin Otters are even better!
Chimbu in a quatering tailwind will sort the big dogs out from the puppies with wet ears in a Dash 8!
If the manufacture fitted reverse thrust to the aeroplane it’s there to use. My technique is to go hard initially in a tight situation if I need it, then onto the brakes at lower speed - I’m talking marginal strip length operations totally IAW the operator’s SOPS. Note that this probably doesn’t exist in OZ for an RPT operator as CASA would probably never approve any such action. I can speak from experience!!!!
Chimbu in a quatering tailwind will sort the big dogs out from the puppies with wet ears in a Dash 8!
If the manufacture fitted reverse thrust to the aeroplane it’s there to use. My technique is to go hard initially in a tight situation if I need it, then onto the brakes at lower speed - I’m talking marginal strip length operations totally IAW the operator’s SOPS. Note that this probably doesn’t exist in OZ for an RPT operator as CASA would probably never approve any such action. I can speak from experience!!!!
There was or is a time limited prohibition range which applied to the smaller F70 engine. Unfortunately the software is the same for both the F70 and F100. The issue is that should this condition be tripped it cannot be cleared by the pilot and cannot continue on until it is, along with any maintenance conditions applied of course in the case of the smaller F70 engine.
Today most dinosaurs have the same problem, there are few if any software engineers who still hold the approvals and skills to make changes to fundamental operational software. Even if there is, since the manufacturer no longer exists who carries responsibility for those changes. It’s not all that simple both software packages must be changed in order to ensure the right software is applied to the right engine. The easier solution is to implement an operating procedure which is less likely to cause the issue. This in itself creates new problems if it’s not though through and most often comes to light literally by accident.
For example for the F50, it came to light that pilots couldn’t be trained reliably to properly reject a takeoff bringing about a significant increase in stop distance. The solution was to lock out reverse and rely on brakes alone. It follows then that the takeoff antiskid inop charts and procedure must be removed also, it wasn’t. I would be curious today as to how many think they can still takeoff with antiskid inop. It will certainly come to light the first time someone rejects a takeoff with no reverse and no antiskid.
Today most dinosaurs have the same problem, there are few if any software engineers who still hold the approvals and skills to make changes to fundamental operational software. Even if there is, since the manufacturer no longer exists who carries responsibility for those changes. It’s not all that simple both software packages must be changed in order to ensure the right software is applied to the right engine. The easier solution is to implement an operating procedure which is less likely to cause the issue. This in itself creates new problems if it’s not though through and most often comes to light literally by accident.
For example for the F50, it came to light that pilots couldn’t be trained reliably to properly reject a takeoff bringing about a significant increase in stop distance. The solution was to lock out reverse and rely on brakes alone. It follows then that the takeoff antiskid inop charts and procedure must be removed also, it wasn’t. I would be curious today as to how many think they can still takeoff with antiskid inop. It will certainly come to light the first time someone rejects a takeoff with no reverse and no antiskid.