RVSM / Standby Altimeter
Thread Starter
Joined: Jan 2001
Posts: 545
Likes: 1
From: Dunstable, Beds UK
RVSM / Standby Altimeter
Have just updated a B727-100 to meet EU RVSM requirements.
The mod was done under an FAA STC ( Supplemental Type Certificate) and included the usual Boeing SB's ( Skin Waviness etc) plus new ADC's and indicators.
Under FAA rules when the work was completed per the STC off you go.
Unfortunately the aircraft is under a register that elects to follow the UK CAA ( Yuk Condem All Aircraft).
Now you have to present all the info to LGW and get an AAN ( Airworthiness Approval Note).
Needless to say we had to re-invent the wheel but then got completely hung up by the CAA requiring a Standby Altimeter Correction chart.
CAA said there is one in the AFM. Called Boeing, purchased a new AFM and surprise - No chart.
CAA said there is one from Boeing - Boeing deny all knowledge
First, anyone any idea where one is available. I assume it is regarding PE for the statics?
Second apart from the fact that the rest of the non CAA world fly quite happily without this essential information what is the use of it ?
If the primary system fails you can no longer maintain RVSM and we are talking of errors in the region of 100- 200 feet on a 3 inch indicator with a needle 50 feet thick and untold hysterysis and parallax. They also want various speed and flap configurations.
Am I missing something in this big picture
As we have just put in a highly accurate calibrated and certified primary system I offered to make a chart by comparing primary to standby in the cruise at altitude but they would not accept this.
Anyone got a chart ?
The mod was done under an FAA STC ( Supplemental Type Certificate) and included the usual Boeing SB's ( Skin Waviness etc) plus new ADC's and indicators.
Under FAA rules when the work was completed per the STC off you go.
Unfortunately the aircraft is under a register that elects to follow the UK CAA ( Yuk Condem All Aircraft).
Now you have to present all the info to LGW and get an AAN ( Airworthiness Approval Note).
Needless to say we had to re-invent the wheel but then got completely hung up by the CAA requiring a Standby Altimeter Correction chart.
CAA said there is one in the AFM. Called Boeing, purchased a new AFM and surprise - No chart.
CAA said there is one from Boeing - Boeing deny all knowledge
First, anyone any idea where one is available. I assume it is regarding PE for the statics?
Second apart from the fact that the rest of the non CAA world fly quite happily without this essential information what is the use of it ?
If the primary system fails you can no longer maintain RVSM and we are talking of errors in the region of 100- 200 feet on a 3 inch indicator with a needle 50 feet thick and untold hysterysis and parallax. They also want various speed and flap configurations.
Am I missing something in this big picture
As we have just put in a highly accurate calibrated and certified primary system I offered to make a chart by comparing primary to standby in the cruise at altitude but they would not accept this.
Anyone got a chart ?
Cunning Artificer
Joined: Jun 2001
Posts: 3,125
Likes: 7
From: The spiritual home of DeHavilland
In RVSM conditions, if either primary altimeter fails you no longer meet RVSM, must declare the situation and descend below 29,000 feet when cleared. Fair enough...
I suppose the UKCAA are then looking at the situation where the remaining primary is more accurate than the standby and there may be a split in the indications. The correction chart would allow the standby altimeter reading to be corrected to enable cross comparison of the two. Lord knows why, but that seems the most reasonable guess. We never had to do this on our B757s or B767s although the same situation applies. Perhaps the B727 standby instrument is known to have a particularly dodgy auxiliary static system?
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Through difficulties to the cinema
I suppose the UKCAA are then looking at the situation where the remaining primary is more accurate than the standby and there may be a split in the indications. The correction chart would allow the standby altimeter reading to be corrected to enable cross comparison of the two. Lord knows why, but that seems the most reasonable guess. We never had to do this on our B757s or B767s although the same situation applies. Perhaps the B727 standby instrument is known to have a particularly dodgy auxiliary static system?
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Through difficulties to the cinema
