Date: 201305
Local time of day: 1201-1800
Location: N90.TRACON, NY
Flight conditions: IMC
Weather elements / visibility: Thunderstorm; Turbulence
Light: Daylight
Aircraft: BAe 125 Series 800
Operating under: Part 91
Mission: Passenger
Flight phase: Landing
Airspace: Class D TEB
ATC / advisory: TRACON N90; Tower TEB
Reporter function: Pilot Not Flying; Captain
Reporter qualification: Flight Crew Air Transport Pilot (ATP)
Human factors: Confusion
Anomaly: Deviation - Altitude Overshoot; Deviation / Discrepancy - Procedural Published Material / Policy; Deviation / Discrepancy - Procedural Clearance; Inflight Event / Encounter Weather / Turbulence
Detector: Person Flight Crew
When detected: In-flight
Result: Flight Crew Became Reoriented; Flight Crew Returned To Clearance
Contributing factors: Chart Or Publication; Human Factors; Weather; Aircraft
Primary problem: Ambiguous

Narrative: After intercepting the glideslope inbound on the ILS 19 into TEB; ATC told the crew that the aircraft we were following had just gone missed at TEB due to low weather; but that the aircraft before him had made it in.  ATC did not state what the current visibility or ceiling was.  The last ATIS received by the crew was 16013G18KT 10SM RA BKN047 BKN060 OVC110 27/19 A2980.  The radar picture revealed numerous rain showers and cells in the area.  The crew elected to continue the approach.  Upon reaching DA; with no runway in sight; a missed approach was executed.  The missed was conducted as briefed; but the crew might have inadvertently climbed above 1;500 feet prior to TROVA.  Although the approach was briefed on the ground at MMU; the First Officer thought the missed approach red make a climbing right turn to 1;500 feet then climb to 3;000 feet upon completion of the turn; while I interpreted it to read that we should cross TROVA at 1;500 feet then climb and maintain 3;000 feet.  1;500 feet was set in the altitude select upon glide slope intercept.  During the missed approach I called out 500 feet climbing 1;500 feet and then continued with my missed approach flow and SNAP check.  By the time I completed my flow/check we were climbing through 1;500 feet and I told the First Officer we were supposed to level at 1;500 feet and then preceded to nose over and return to 1;500 feet.  Upon checking in with Approach (prior to TROVA) [we] were given a climb to 2;000 feet and vectors to the northwest.  The flight continued uneventfully to a normal landing without further incident.   The published missed approach procedure could be revised to remove some ambiguity as to whether 1;500 feet at TROVA is mandatory (much like the approach plates for the ILS 6 has DANDY at 1;500 feet or the TEB 8 SID has a note to cross 4.8 dme AT 1;500 feet). Even changing the wording to:  Immediate climbing right turn to 1;500 via heading 205 and TEB VOR/DME R-278 to cross TROVA/4.7  DME AT 1;500 feet; then climb to 3;000 via TEB R-278 to MORNS INT and hold; would remove any ambiguity as to what the aircraft is supposed to do.  Complicating this was a short flight in a high workload environment; with unforecasted weather; and a relatively low time (first rotation following IOE) First Officer.  Also; the light weight of the aircraft (~18;800lbs) allowed us to climb much quicker than normal and with only 1;200 feet to climb; gave much less time to catch and trap the error.  Lastly; the +RA; low IMC; and moderate turbulence encountered during the missed all contributed to our workload during the possible altitude deviation.




Synopsis: BAE125 Captain reports confusion over the altitude to be maintained initially on the missed approach from the ILS 19 at TEB.  The flying First Officer believes the climb is to 3;000 feet but the Captain helps him return to 1;500 feet.